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Updated: 2017-07-25T02:14:42.778-07:00

 



So there I was, firing a megawatt plasma collider at work...

2017-07-25T02:14:42.802-07:00

Posted by Ted Baltz, Senior Staff Software Engineer, Google Accelerated Science TeamWait, what? Why is Google interested in plasma physics?Google is always interested in solving complex engineering problems, and few are more complex than fusion. Physicists have been trying since the 1950s to control the fusion of hydrogen atoms into helium, which is the same process that powers the Sun. The key to harnessing this power is to confine hydrogen plasmas for long enough to get more energy out from fusion reactions than was put in. This point is called “breakeven.” If it works, it would represent a technological breakthrough, and could provide an abundant source of zero-carbon energy.There are currently several large academic and government research efforts in fusion. Just to rattle off a few, in plasma fusion there are tokamak machines like ITER and stellarator machines like Wendelstein 7-X. The stellarator design actually goes back to 1951, so physicists have been working on this for a while. Oh yeah, and if you like giant lasers, there’s the National Ignition Facility which users lasers to generate X-rays to generate fusion reactions. So far, none of these has gotten to the economic breakeven point.All of these efforts involve complex experiments with many variables, providing an opportunity for Google to help, with our strength in computing and machine learning. Today, we’re publishing “Achievement of Sustained Net Plasma Heating in a Fusion Experiment with the Optometrist Algorithm” in Scientific Reports. This paper describes the first results of Google’s collaboration with the physicists and engineers at Tri Alpha Energy, taking a step towards the breakeven goal.Did you really just say that you got to fire a plasma collider?Yeah. Tri Alpha Energy has a unique scheme for plasma confinement called a field-reversed configuration that’s predicted to get more stable as the energy goes up, in contrast to other methods where plasmas get harder to control as you heat them. Tri Alpha built a giant ionized plasma machine, C-2U, that fills an entire warehouse in an otherwise unassuming office park. The plasma that this machine generates and confines exhibits all kinds of highly nonlinear behavior. The machine itself pushes the envelope of how much electrical power can be applied to generate and confine the plasma in such a small space over such a short time. It’s a complex machine with more than 1000 knobs and switches, an investment (not ours!) in exploring clean energy north of $100 million. This is a high-stakes optimization problem, dealing with both plasma performance and equipment constraints. This is where Google comes in.End-on view of C-2UWait, why not just simulate what will happen? Isn’t this simple physics?The “simple” simulations using magnetohydrodynamics don’t really apply. Even if these machines operated in that limit, which they very much don’t, the simulations make fluid dynamics simulations look easy! The reality is much more complicated, as the ion temperature is three times larger than the electron temperature, so the plasma is far out of thermal equilibrium, also, the fluid approximation is totally invalid, so you have to track at least some of the trillion+ individual particles, so the whole thing is beyond what we know how to do even with Google-scale compute resources.So why are we doing this? Real experiments! With atoms not bits! At Google we love to run experiments and optimize things. We thought it would be a great challenge to see if we could help Tri Alpha. They run a plasma “shot” on the C-2U machine every 8 minutes. Each shot consists of creating two spinning blobs of plasma in the vacuum sealed innards of C-2U, smashing them together at over 600,000 miles per hour, creating a bigger, hotter, spinning football of plasma. Then they blast it continuously with particle beams (actually neutral hydrogen atoms) to keep it spinning. They hang on to the spinning football with magnetic fields for as long as 10 milliseconds. They’re trying to experimentally verify that the[...]



Teaching Robots to Understand Semantic Concepts

2017-07-21T12:45:12.144-07:00

Posted by Sergey Levine, Faculty Advisor and Pierre Sermanet, Research Scientist, Google Brain TeamMachine learning can allow robots to acquire complex skills, such as grasping and opening doors. However, learning these skills requires us to manually program reward functions that the robots then attempt to optimize. In contrast, people can understand the goal of a task just from watching someone else do it, or simply by being told what the goal is. We can do this because we draw on our own prior knowledge about the world: when we see someone cut an apple, we understand that the goal is to produce two slices, regardless of what type of apple it is, or what kind of tool is used to cut it. Similarly, if we are told to pick up the apple, we understand which object we are to grab because we can ground the word “apple” in the environment: we know what it means. These are semantic concepts: salient events like producing two slices, and object categories denoted by words such as “apple.” Can we teach robots to understand semantic concepts, to get them to follow simple commands specified through categorical labels or user-provided examples? In this post, we discuss some of our recent work on robotic learning that combines experience that is autonomously gathered by the robot, which is plentiful but lacks human-provided labels, with human-labeled data that allows a robot to understand semantics. We will describe how robots can use their experience to understand the salient events in a human-provided demonstration, mimic human movements despite the differences between human robot bodies, and understand semantic categories, like “toy” and “pen”, to pick up objects based on user commands.Understanding human demonstrations with deep visual featuresIn the first set of experiments, which appear in our paper Unsupervised Perceptual Rewards for Imitation Learning, our is aim is to enable a robot to understand a task, such as opening a door, from seeing only a small number of unlabeled human demonstrations. By analyzing these demonstrations, the robot must understand what is the semantically salient event that constitutes task success, and then use reinforcement learning to perform it.Examples of human demonstrations (left) and the corresponding robotic imitation (right).Unsupervised learning on very small datasets is one of the most challenging scenarios in machine learning. To make this feasible, we use deep visual features from a large network trained for image recognition on ImageNet. Such features are known to be sensitive to semantic concepts, while maintaining invariance to nuisance variables such as appearance and lighting. We use these features to interpret user-provided demonstrations, and show that it is indeed possible to learn reward functions in an unsupervised fashion from a few demonstrations and without retraining.Example of reward functions learned solely from observation for the door opening tasks. Rewards progressively increase from zero to the maximum reward as a task is completed.After learning a reward function from observation only, we use it to guide a robot to learn a door opening task, using only the images to evaluate the reward function. With the help of an initial kinesthetic demonstration that succeeds about 10% of the time, the robot learns to improve to 100% accuracy using the learned reward function.Learning progression.Emulating human movements with self-supervision and imitation.In Time-Contrastive Networks: Self-Supervised Learning from Multi-View Observation, we propose a novel approach to learn about the world from observation and demonstrate it through self-supervised pose imitation. Our approach relies primarily on co-occurrence in time and space for supervision: by training to distinguish frames from different times of a video, it learns to disentangle and organize reality into useful abstract representations. In a pose imitation task for example, different dimensions of the representation may encode for different joints of a human or robotic body. Rather[...]



Google at CVPR 2017

2017-07-21T08:00:06.778-07:00

Posted by Christian Howard, Editor-in-Chief, Research CommunicationsFrom July 21-26, Honolulu, Hawaii hosts the 2017 Conference on Computer Vision and Pattern Recognition (CVPR 2017), the premier annual computer vision event comprising the main conference and several co-located workshops and tutorials. As a leader in computer vision research and a Platinum Sponsor, Google will have a strong presence at CVPR 2017 — over 250 Googlers will be in attendance to present papers and invited talks at the conference, and to organize and participate in multiple workshops.If you are attending CVPR this year, please stop by our booth and chat with our researchers who are actively pursuing the next generation of intelligent systems that utilize the latest machine learning techniques applied to various areas of machine perception. Our researchers will also be available to talk about and demo several recent efforts, including the technology behind Headset Removal for Virtual and Mixed Reality, Image Compression with Neural Networks, Jump, TensorFlow Object Detection API and much more.You can learn more about our research being presented at CVPR 2017 in the list below (Googlers highlighted in blue).Organizing CommitteeCorporate Relations Chair - Mei HanArea Chairs include - Alexander Toshev, Ce Liu, Vittorio Ferrari, David LowePapersTraining object class detectors with click supervisionDim Papadopoulos, Jasper Uijlings, Frank Keller, Vittorio FerrariUnsupervised Pixel-Level Domain Adaptation With Generative Adversarial NetworksKonstantinos Bousmalis, Nathan Silberman, David Dohan, Dumitru Erhan, Dilip KrishnanBranchOut: Regularization for Online Ensemble Tracking With Convolutional Neural Networks Bohyung Han, Jack Sim, Hartwig Adam Enhancing Video Summarization via Vision-Language EmbeddingBryan A. Plummer, Matthew Brown, Svetlana LazebnikLearning by Association — A Versatile Semi-Supervised Training Method for Neural Networks Philip Haeusser, Alexander Mordvintsev, Daniel CremersContext-Aware Captions From Context-Agnostic SupervisionRamakrishna Vedantam, Samy Bengio, Kevin Murphy, Devi Parikh, Gal Chechik Spatially Adaptive Computation Time for Residual NetworksMichael Figurnov, Maxwell D. Collins, Yukun Zhu, Li Zhang, Jonathan Huang, Dmitry Vetrov, Ruslan SalakhutdinovXception: Deep Learning With Depthwise Separable ConvolutionsFrançois Chollet Deep Metric Learning via Facility LocationHyun Oh Song, Stefanie Jegelka, Vivek Rathod, Kevin MurphySpeed/Accuracy Trade-Offs for Modern Convolutional Object DetectorsJonathan Huang, Vivek Rathod, Chen Sun, Menglong Zhu, Anoop Korattikara, Alireza Fathi, Ian Fischer, Zbigniew Wojna, Yang Song, Sergio Guadarrama, Kevin MurphySynthesizing Normalized Faces From Facial Identity FeaturesForrester Cole, David Belanger, Dilip Krishnan, Aaron Sarna, Inbar Mosseri, William T. FreemanTowards Accurate Multi-Person Pose Estimation in the WildGeorge Papandreou, Tyler Zhu, Nori Kanazawa, Alexander Toshev, Jonathan Tompson, Chris Bregler, Kevin MurphyGuessWhat?! Visual Object Discovery Through Multi-Modal DialogueHarm de Vries, Florian Strub, Sarath Chandar, Olivier Pietquin, Hugo Larochelle, Aaron CourvilleLearning discriminative and transformation covariant local feature detectorsXu Zhang, Felix X. Yu, Svebor Karaman, Shih-Fu ChangFull Resolution Image Compression With Recurrent Neural NetworksGeorge Toderici, Damien Vincent, Nick Johnston, Sung Jin Hwang, David Minnen, Joel Shor, Michele CovellLearning From Noisy Large-Scale Datasets With Minimal SupervisionAndreas Veit, Neil Alldrin, Gal Chechik, Ivan Krasin, Abhinav Gupta, Serge BelongieUnsupervised Learning of Depth and Ego-Motion From VideoTinghui Zhou, Matthew Brown, Noah Snavely, David G. Lowe Cognitive Mapping and Planning for Visual NavigationSaurabh Gupta, James Davidson, Sergey Levine,[...]



An Update to Open Images - Now with Bounding-Boxes

2017-07-20T14:41:08.669-07:00



Last year we introduced Open Images, a collaborative release of ~9 million images annotated with labels spanning over 6000 object categories, designed to be a useful dataset for machine learning research. The initial release featured image-level labels automatically produced by a computer vision model similar to Google Cloud Vision API, for all 9M images in the training set, and a validation set of 167K images with 1.2M human-verified image-level labels.

Today, we introduce an update to Open Images, which contains the addition of a total of ~2M bounding-boxes to the existing dataset, along with several million additional image-level labels. Details include:
  • 1.2M bounding-boxes around objects for 600 categories on the training set. These have been produced semi-automatically by an enhanced version of the technique outlined in [1], and are all human-verified.
  • Complete bounding-box annotation for all object instances of the 600 categories on the validation set, all manually drawn (830K boxes). The bounding-box annotations in the training and validations sets will enable research on object detection on this dataset. The 600 categories offer a broader range than those in the ILSVRC and COCO detection challenges, and include new objects such as fedora hat and snowman.
  • 4.3M human-verified image-level labels on the training set (over all categories). This will enable large-scale experiments on object classification, based on a clean training set with reliable labels.
(image)
Annotated images from the Open Images dataset. Left: FAMILY MAKING A SNOWMAN by mwvchamber. Right: STANZA STUDENTI.S.S. ANNUNZIATA by ersupalermo. Both images used under CC BY 2.0 license. See more examples here.
We hope that this update to Open Images will stimulate the broader research community to experiment with object classification and detection models, and facilitate the development and evaluation of new techniques.

References
[1] We don't need no bounding-boxes: Training object class detectors using only human verification, Papadopoulos, Uijlings, Keller, and Ferrari, CVPR 2016(image)



Motion Stills — Now on Android

2017-07-20T08:31:09.981-07:00

Posted by Karthik Raveendran and Suril Shah, Software Engineers, Google ResearchLast year, we launched Motion Stills, an iOS app that stabilizes your Live Photos and lets you view and share them as looping GIFs and videos. Since then, Motion Stills has been well received, being listed as one of the top apps of 2016 by The Verge and Mashable. However, from its initial release, the community has been asking us to also make Motion Stills available for Android. We listened to your feedback and today, we're excited to announce that we’re bringing this technology, and more, to devices running Android 5.1 and later!Motion Stills on Android: Instant stabilization on your device.With Motion Stills on Android we built a new recording experience where everything you capture is instantly transformed into delightful short clips that are easy to watch and share. You can capture a short Motion Still with a single tap like a photo, or condense a longer recording into a new feature we call Fast Forward. In addition to stabilizing your recordings, Motion Stills on Android comes with an improved trimming algorithm that guards against pocket shots and accidental camera shakes. All of this is done during capture on your Android device, no internet connection required!New streaming pipelineFor this release, we redesigned our existing iOS video processing pipeline to use a streaming approach that processes each frame of a video as it is being recorded. By computing intermediate motion metadata, we are able to immediately stabilize the recording while still performing loop optimization over the full sequence. All this leads to instant results after recording — no waiting required to share your new GIF.Capture using our streaming pipeline gives you instant results.In order to display your Motion Stills stream immediately, our algorithm computes and stores the necessary stabilizing transformation as a low resolution texture map. We leverage this texture to apply the stabilization transform using the GPU in real-time during playback, instead of writing a new, stabilized video that would tax your mobile hardware and battery.Fast ForwardFast Forward allows you to speed up and condense a longer recording into a short, easy to share clip. The same pipeline described above allows Fast Forward to process up to a full minute of video, right on your phone. You can even change the speed of playback (from 1x to 8x) after recording. To make this possible, we encode videos with a denser I-frame spacing to enable efficient seeking and playback. We also employ additional optimizations in the Fast Forward mode. For instance, we apply adaptive temporal downsampling in the linear solver and long-range stabilization for smooth results over the whole sequence. Fast Forward condenses your recordings into easy to share clips.Try out Motion StillsMotion Stills is an app for us to experiment and iterate quickly with short-form video technology, gathering valuable feedback along the way. The tools our users find most fun and useful may be integrated later on into existing products like Google Photos. Download Motion Stills for Android from the Google Play store—available for mobile phones running Android 5.1 and later—and share your favorite clips on social media with hashtag #motionstills. AcknowledgementsMotion Stills would not have been possible without the help of many Googlers. We want to especially acknowledge the work of Matthias Grundmann in advancing our stabilization technology, as well as our UX and interaction designers Jacob Zukerman, Ashley Ma and Mark Bowers. [...]



Facets: An Open Source Visualization Tool for Machine Learning Training Data

2017-07-17T11:00:23.204-07:00

Posted by James Wexler, Senior Software Engineer, Google Big Picture Team(Cross-posted on the Google Open Source Blog)Getting the best results out of a machine learning (ML) model requires that you truly understand your data. However, ML datasets can contain hundreds of millions of data points, each consisting of hundreds (or even thousands) of features, making it nearly impossible to understand an entire dataset in an intuitive fashion. Visualization can help unlock nuances and insights in large datasets. A picture may be worth a thousand words, but an interactive visualization can be worth even more.Working with the PAIR initiative, we’ve released Facets, an open source visualization tool to aid in understanding and analyzing ML datasets. Facets consists of two visualizations that allow users to see a holistic picture of their data at different granularities. Get a sense of the shape of each feature of the data using Facets Overview, or explore a set of individual observations using Facets Dive. These visualizations allow you to debug your data which, in machine learning, is as important as debugging your model. They can easily be used inside of Jupyter notebooks or embedded into webpages. In addition to the open source code, we've also created a Facets demo website. This website allows anyone to visualize their own datasets directly in the browser without the need for any software installation or setup, without the data ever leaving your computer. Facets OverviewFacets Overview automatically gives users a quick understanding of the distribution of values across the features of their datasets. Multiple datasets, such as a training set and a test set, can be compared on the same visualization. Common data issues that can hamper machine learning are pushed to the forefront, such as: unexpected feature values, features with high percentages of missing values, features with unbalanced distributions, and feature distribution skew between datasets.Facets Overview visualization of the six numeric features of the UCI Census datasets[1]. The features are sorted by non-uniformity, with the feature with the most non-uniform distribution at the top. Numbers in red indicate possible trouble spots, in this case numeric features with a high percentage of values set to 0. The histograms at right allow you to compare the distributions between the training data (blue) and test data (orange).Facets Overview visualization showing two of the nine categorical features of the UCI Census datasets[1]. The features are sorted by distribution distance, with the feature with the biggest skew between the training (blue) and test (orange) datasets at the top. Notice in the “Target” feature that the label values differ between the training and test datasets, due to a trailing period in the test set (“<=50K” vs “<=50K.”). This can be seen in the chart for the feature and also in the entries in the “top” column of the table. This label mismatch would cause a model trained and tested on this data to not be evaluated correctly.Facets DiveFacets Dive provides an easy-to-customize, intuitive interface for exploring the relationship between the data points across the different features of a dataset. With Facets Dive, you control the position, color and visual representation of each data point based on its feature values. If the data points have images associated with them, the images can be used as the visual representations.Facets Dive visualization showing all 16281 data points in the UCI Census test dataset[1]. The animation shows a user coloring the data points by one feature (“Relationship”), faceting in one dimension by a continuous feature (“Age”) and then faceting in another dimension by a discrete feature (“Marital Status”).Facets Dive visualization of a large number of face drawings from the “Quick, Draw!” Dataset, showing the relationship between the number of strokes and[...]



Using Deep Learning to Create Professional-Level Photographs

2017-07-13T18:22:54.420-07:00

Posted by Hui Fang, Software Engineer, Machine PerceptionMachine learning (ML) excels in many areas with well defined goals. Tasks where there exists a right or wrong answer help with the training process and allow the algorithm to achieve its desired goal, whether it be correctly identifying objects in images or providing a suitable translation from one language to another. However, there are areas where objective evaluations are not available. For example, whether a photograph is beautiful is measured by its aesthetic value, which is a highly subjective concept. A professional(?) photograph of Jasper National Park, Canada.To explore how ML can learn subjective concepts, we introduce an experimental deep-learning system for artistic content creation. It mimics the workflow of a professional photographer, roaming landscape panoramas from Google Street View and searching for the best composition, then carrying out various postprocessing operations to create an aesthetically pleasing image. Our virtual photographer “travelled” ~40,000 panoramas in areas like the Alps, Banff and Jasper National Parks in Canada, Big Sur in California and Yellowstone National Park, and returned with creations that are quite impressive, some even approaching professional quality — as judged by professional photographers.Training the ModelWhile aesthetics can be modelled using datasets like AVA, using it naively to enhance photos may miss some aspect in aesthetics, such as making a photo over-saturated. Using supervised learning to learn multiple aspects in aesthetics properly, however, may require a labelled dataset that is intractable to collect. Our approach relies only on a collection of professional quality photos, without before/after image pairs, or any additional labels. It breaks down aesthetics into multiple aspects automatically, each of which is learned individually with negative examples generated by a coupled image operation. By keeping these image operations semi-”orthogonal”, we can enhance a photo on its composition, saturation/HDR level and dramatic lighting with fast and separable optimizations:A panorama (a) is cropped into (b), with saturation and HDR strength enhanced in (c), and with dramatic mask applied in (d). Each step is guided by one learned aspect of aesthetics.A traditional image filter was used to generate negative training examples for saturation, HDR detail and composition. We also introduce a special operation named dramatic mask, which was created jointly while learning the concept of dramatic lighting. The negative examples were generated by applying a combination of image filters that modify brightness randomly on professional photos, degrading their appearance. For the training we use a generative adversarial network (GAN), where a generative model creates a mask to fix lighting for negative examples, while a discriminative model tries to distinguish enhanced results from the real professional ones. Unlike shape-fixed filters such as vignette, dramatic mask adds content-aware brightness adjustment to a photo. The competitive nature of GAN training leads to good variations of such suggestions. You can read more about the training details in our paper.ResultsSome creations of our system from Google Street View are shown below. As you can see, the application of the trained aesthetic filters creates some dramatic results (including the image we started this post with!):Jasper National Park, Canada.Interlaken, Switzerland.Park Parco delle Orobie Bergamasche, Italy.Jasper National Park, Canada.Professional EvaluationTo judge how successful our algorithm was, we designed a “Turing-test”-like experiment: we mix our creations with other photos at different quality, and show them to several professional photographers. They were instructed to assign a quality score for each of them, with meaning defined as following:1: Point-and-shoot witho[...]



Building Your Own Neural Machine Translation System in TensorFlow

2017-07-12T11:30:11.004-07:00

Posted by Thang Luong, Research Scientist, and Eugene Brevdo, Staff Software Engineer, Google Brain TeamMachine translation – the task of automatically translating between languages – is one of the most active research areas in the machine learning community. Among the many approaches to machine translation, sequence-to-sequence ("seq2seq") models [1, 2] have recently enjoyed great success and have become the de facto standard in most commercial translation systems, such as Google Translate, thanks to its ability to use deep neural networks to capture sentence meanings. However, while there is an abundance of material on seq2seq models such as OpenNMT or tf-seq2seq, there is a lack of material that teaches people both the knowledge and the skills to easily build high-quality translation systems.Today we are happy to announce a new Neural Machine Translation (NMT) tutorial for TensorFlow that gives readers a full understanding of seq2seq models and shows how to build a competitive translation model from scratch. The tutorial is aimed at making the process as simple as possible, starting with some background knowledge on NMT and walking through code details to build a vanilla system. It then dives into the attention mechanism [3, 4], a key ingredient that allows NMT systems to handle long sentences. Finally, the tutorial provides details on how to replicate key features in the Google’s NMT (GNMT) system [5] to train on multiple GPUs. The tutorial also contains detailed benchmark results, which users can replicate on their own. Our models provide a strong open-source baseline with performance on par with GNMT results [5]. We achieve 24.4 BLEU points on the popular WMT’14 English-German translation task.Other benchmark results (English-Vietnamese, German-English) can be found in the tutorial.In addition, this tutorial showcases the fully dynamic seq2seq API (released with TensorFlow 1.2) aimed at making building seq2seq models clean and easy:Easily read and preprocess dynamically sized input sequences using the new input pipeline in tf.contrib.data.Use padded batching and sequence length bucketing to improve training and inference speeds.Train seq2seq models using popular architectures and training schedules, including several types of attention and scheduled sampling.Perform inference in seq2seq models using in-graph beam search.Optimize seq2seq models for multi-GPU settings.We hope this will help spur the creation of, and experimentation with, many new NMT models by the research community. To get started on your own research, check out the tutorial on GitHub!Core contributorsThang Luong, Eugene Brevdo, and Rui Zhao. AcknowledgementsWe would like to especially thank our collaborator on the NMT project, Rui Zhao. Without his tireless effort, this tutorial would not have been possible. Additional thanks go to Denny Britz, Anna Goldie, Derek Murray, and Cinjon Resnick for their work bringing new features to TensorFlow and the seq2seq library. Lastly, we thank Lukasz Kaiser for the initial help on the seq2seq codebase; Quoc Le for the suggestion to replicate GNMT; Yonghui Wu and Zhifeng Chen for details on the GNMT systems; as well as the Google Brain team for their support and feedback!References[1] Sequence to sequence learning with neural networks, Ilya Sutskever, Oriol Vinyals, and Quoc V. Le. NIPS, 2014.[2] Learning phrase representations using RNN encoder-decoder for statistical machine translation, Kyunghyun Cho, Bart Van Merrienboer, Caglar Gulcehre, Dzmitry Bahdanau, Fethi Bougares, Holger Schwenk, and Yoshua Bengio. EMNLP 2014.[3] Neural machine translation by jointly learning to align and translate, Dzmitry Bahdanau, Kyunghyun Cho, and Yoshua Bengio. ICLR, 2015. [4] Effective approaches to attention-based neural machine translation, Minh-Thang Luong, Hieu Pham, and Christopher D Manning. EMNLP, 2015. [5] Google’s Neu[...]



Revisiting the Unreasonable Effectiveness of Data

2017-07-11T13:27:39.507-07:00

Posted by Abhinav Gupta, Faculty Advisor, Machine PerceptionThere has been remarkable success in the field of computer vision over the past decade, much of which can be directly attributed to the application of deep learning models to this machine perception task. Furthermore, since 2012 there have been significant advances in representation capabilities of these systems due to (a) deeper models with high complexity, (b) increased computational power and (c) availability of large-scale labeled data. And while every year we get further increases in computational power and the model complexity (from 7-layer AlexNet to 101-layer ResNet), available datasets have not scaled accordingly. A 101-layer ResNet with significantly more capacity than AlexNet is still trained with the same 1M images from ImageNet circa 2011. As researchers, we have always wondered: if we scale up the amount of training data 10x, will the accuracy double? How about 100x or maybe even 300x? Will the accuracy plateau or will we continue to see increasing gains with more and more data?While GPU computation power and model sizes have continued to increase over the last five years, the size of the largest training dataset has surprisingly remained constant.In our paper, “Revisiting Unreasonable Effectiveness of Data in Deep Learning Era”, we take the first steps towards clearing the clouds of mystery surrounding the relationship between `enormous data' and deep learning. Our goal was to explore: (a) if visual representations can be still improved by feeding more and more images with noisy labels to currently existing algorithms; (b) the nature of the relationship between data and performance on standard vision tasks such as classification, object detection and image segmentation; (c) state-of-the-art models for all the tasks in computer vision using large-scale learning.Of course, the elephant in the room is where can we obtain a dataset that is 300x larger than ImageNet? At Google, we have been continuously working on building such datasets automatically to improve computer vision algorithms. Specifically, we have built an internal dataset of 300M images that are labeled with 18291 categories, which we call JFT-300M. The images are labeled using an algorithm that uses complex mixture of raw web signals, connections between web-pages and user feedback. This results in over one billion labels for the 300M images (a single image can have multiple labels). Of the billion image labels, approximately 375M are selected via an algorithm that aims to maximize label precision of selected images. However, there is still considerable noise in the labels: approximately 20% of the labels for selected images are noisy. Since there is no exhaustive annotation, we have no way to estimate the recall of the labels.Our experimental results validate some of the hypotheses but also generate some unexpected surprises:Better Representation Learning Helps. Our first observation is that large-scale data helps in representation learning which in-turn improves the performance on each vision task we study. Our findings suggest that a collective effort to build a large-scale dataset for pretraining is important. It also suggests a bright future for unsupervised and semi-supervised representation learning approaches. It seems the scale of data continues to overpower noise in the label space.Performance increases linearly with orders of magnitude of training data.  Perhaps the most surprising finding is the relationship between performance on vision tasks and the amount of training data (log-scale) used for representation learning. We find that this relationship is still linear! Even at 300M training images, we do not observe any plateauing effect for the tasks studied.Object detection performance when pre-trained on different subsets of JFT-300M from scratch[...]



The Google Brain Residency Program — One Year Later

2017-07-20T14:45:29.041-07:00

Posted by Luke Metz, Research Associate and Yun Liu, Software Engineer, 2016 Google Brain Resident Alumni“Coming from a background in statistics, physics, and chemistry, the Google Brain Residency was my first exposure to both deep learning and serious programming. I enjoyed the autonomy that I was given to research diverse topics of my choosing: deep learning for computer vision and language, reinforcement learning, and theory. I originally intended to pursue a statistics PhD but my experience here spurred me to enroll in the Stanford CS program starting this fall!”- Melody Guan, 2016 Google Brain Residency AlumnaThis month marks the end of an incredibly successful year for our first class of the Google Brain Residency Program. This one-year program was created as an opportunity for individuals from diverse educational backgrounds and experiences to dive into research in machine learning and deep learning. Over the past year, the Residents familiarized themselves with the literature, designed and implemented experiments at Google scale, and engaged in cutting edge research in a wide variety of subjects ranging from theory to robotics to music generation.To date, the inaugural class of Residents have published over 30 papers at leading machine learning publication venues such as ICLR (15), ICML (11), CVPR (3), EMNLP (2), RSS, GECCO, ISMIR, ISMB and Cosyne. An additional 18 papers are currently under review at NIPS, ICCV, BMVC and Nature Methods. Two of the above papers were published in Distill, exploring how deconvolution causes checkerboard artifacts and presenting ways of visualizing a generative model of handwriting. A Distill article by residents interactively explores how a neural network generates handwriting.A system that explores how robots can learn to imitate human motion from observation. For more details, see “Time-Contrastive Networks: Self-Supervised Learning from Multi-View Observation” (Co-authored by Resident Corey Lynch, along with P. Sermanet, , J. Hsu, S. Levine, accepted to CVPR Workshop 2017)A model that uses reinforcement learning to train distributed deep learning networks at large scale by optimizing computations to hardware devices assignment. For more details, see “Device Placement Optimization with Reinforcement Learning” (Co-authored by Residents Azalia Mirhoseini and Hieu Pham, along with Q. Le, B. Steiner, R. Larsen, Y. Zhou, N. Kumar, M. Norouzi, S. Bengio, J. Dean, submitted to ICML 2017).An approach to automate the process of discovering optimization methods, with a focus on deep learning architectures. Final version of the paper “Neural Optimizer Search with Reinforcement Learning” (Co-authored by Residents Irwan Bello and Barret Zoph, along with V. Vasudevan, Q. Le, submitted to ICML 2017) coming soon.Residents have also made significant contributions to the open source community with general-purpose sequence-to-sequence models (used for example in translation), music synthesis, mimicking human sketching, subsampling a sequence for model training, an efficient “attention” mechanism for models, and time series analysis (particularly for neuroscience).The end of the program year marks our Residents embarking on the next stages in their careers. Many are continuing their research careers on the Google Brain team as full time employees. Others have chosen to enter top machine learning Ph.D. programs at schools such as Stanford University, UC Berkeley, Cornell University, Oxford University and NYU, University of Toronto and CMU. We could not be more proud to see where their hard work and experiences will take them next!As we “graduate” our first class, this week we welcome our next class of 35 incredibly talented Residents who have joined us from a wide range of experience and education backgrounds. We can’t wait to see h[...]



MultiModel: Multi-Task Machine Learning Across Domains

2017-06-21T10:18:18.993-07:00

Posted by Łukasz Kaiser, Senior Research Scientist, Google Brain Team and Aidan N. Gomez, Researcher, Department of Computer Science Machine Learning Group, University of TorontoOver the last decade, the application and performance of Deep Learning has progressed at an astonishing rate. However, the current state of the field is that the neural network architectures are highly specialized to specific domains of application. An important question remains unanswered: Will a convergence between these domains facilitate a unified model capable of performing well across multiple domains?Today, we present MultiModel, a neural network architecture that draws from the success of vision, language and audio networks to simultaneously solve a number of problems spanning multiple domains, including image recognition, translation and speech recognition. While strides have been made in this direction before, namely in Google’s Multilingual Neural Machine Translation System used in Google Translate, MultiModel is a first step towards the convergence of vision, audio and language understanding into a single network.The inspiration for how MultiModel handles multiple domains comes from how the brain transforms sensory input from different modalities (such as sound, vision or taste), into a single shared representation and back out in the form of language or actions. As an analog to these modalities and the transformations they perform, MultiModel has a number of small modality-specific sub-networks for audio, images, or text, and a shared model consisting of an encoder, input/output mixer and decoder, as illustrated below.MultiModel architecture: small modality-specific sub-networks work with a shared encoder, I/O mixer and decoder. Each petal represents a modality, transforming to and from the internal representation.We demonstrate that MultiModel is capable of learning eight different tasks simultaneously: it can detect objects in images, provide captions, recognize speech, translate between four pairs of languages, and do grammatical constituency parsing at the same time. The input is given to the model together with a very simple signal that determines which output we are requesting. Below we illustrate a few examples taken from a MultiModel trained jointly on these eight tasks1:When designing MultiModel it became clear that certain elements from each domain of research (vision, language and audio) were integral to the model’s success in related tasks. We demonstrate that these computational primitives (such as convolutions, attention, or mixture-of-experts layers) clearly improve performance on their originally intended domain of application, while not hindering MultiModel’s performance on other tasks. It is not only possible to achieve good performance while training jointly on multiple tasks, but on tasks with limited quantities of data, the performance actually improves. To our surprise, this happens even if the tasks come from different domains that would appear to have little in common, e.g., an image recognition task can improve performance on a language task.It is important to note that while MultiModel does not establish new performance records, it does provide insight into the dynamics of multi-domain multi-task learning in neural networks, and the potential for improved learning on data-limited tasks by the introduction of auxiliary tasks. There is a longstanding saying in machine learning: “the best regularizer is more data”; in MultiModel, this data can be sourced across domains, and consequently can be obtained more easily than previously thought. MultiModel provides evidence that training in concert with other tasks can lead to good results and improve performance on data-limited tasks.Many questions about multi-domain machine learning rem[...]



Accelerating Deep Learning Research with the Tensor2Tensor Library

2017-06-19T14:37:02.473-07:00

Posted by Łukasz Kaiser, Senior Research Scientist, Google Brain TeamDeep Learning (DL) has enabled the rapid advancement of many useful technologies, such as machine translation, speech recognition and object detection. In the research community, one can find code open-sourced by the authors to help in replicating their results and further advancing deep learning. However, most of these DL systems use unique setups that require significant engineering effort and may only work for a specific problem or architecture, making it hard to run new experiments and compare the results.Today, we are happy to release Tensor2Tensor (T2T), an open-source system for training deep learning models in TensorFlow. T2T facilitates the creation of state-of-the art models for a wide variety of ML applications, such as translation, parsing, image captioning and more, enabling the exploration of various ideas much faster than previously possible. This release also includes a library of datasets and models, including the best models from a few recent papers (Attention Is All You Need, Depthwise Separable Convolutions for Neural Machine Translation and One Model to Learn Them All) to help kick-start your own DL research. Translation Model Training time BLEU (difference from baseline) Transformer (T2T) 3 days on 8 GPU 28.4 (+7.8) SliceNet (T2T) 6 days on 32 GPUs 26.1 (+5.5) GNMT + Mixture of Experts 1 day on 64 GPUs 26.0 (+5.4) ConvS2S 18 days on 1 GPU 25.1 (+4.5) GNMT 1 day on 96 GPUs 24.6 (+4.0) ByteNet 8 days on 32 GPUs 23.8 (+3.2) MOSES (phrase-based baseline) N/A 20.6 (+0.0) BLEU scores (higher is better) on the standard WMT English-German translation task.As an example of the kind of improvements T2T can offer, we applied the library to machine translation. As you can see in the table above, two different T2T models, SliceNet and Transformer, outperform the previous state-of-the-art, GNMT+MoE. Our best T2T model, Transformer, is 3.8 points better than the standard GNMT model, which itself was 4 points above the baseline phrase-based translation system, MOSES. Notably, with T2T you can approach previous state-of-the-art results with a single GPU in one day: a small Transformer model (not shown above) gets 24.9 BLEU after 1 day of training on a single GPU. Now everyone with a GPU can tinker with great translation models on their own: our github repo has instructions on how to do that. Modular Multi-Task TrainingThe T2T library is built with familiar TensorFlow tools and defines multiple pieces needed in a deep learning system: data-sets, model architectures, optimizers, learning rate decay schemes, hyperparameters, and so on. Crucially, it enforces a standard interface between all these parts and implements current ML best practices. So you can pick any data-set, model, optimizer and set of hyperparameters, and run the training to check how it performs. We made the architecture modular, so every piece between the input data and the predicted output is a tensor-to-tensor function. If you have a new idea for the model architecture, you don’t need to replace the whole setup. You can keep the embedding part and the loss and everything else, just replace the model body by your own function that takes a tensor as input and returns a tensor. This means that T2T is flexible, with training no longer pinned to a specific model or dataset. It is so easy that even architectures like the famous LSTM sequence-to-sequence model can be defined in a few dozen lines of code. One can also train a single model on multiple tasks from different domains. Taken to the limit, you can even train a single model on all data-sets concurrently, and we are happy to report that our MultiModel, trained like this and included in T2T, yields good results on many[...]



Supercharge your Computer Vision models with the TensorFlow Object Detection API

2017-06-20T11:42:53.920-07:00

Posted by Jonathan Huang, Research Scientist and Vivek Rathod, Software Engineer(Cross-posted on the Google Open Source Blog)At Google, we develop flexible state-of-the-art machine learning (ML) systems for computer vision that not only can be used to improve our products and services, but also spur progress in the research community. Creating accurate ML models capable of localizing and identifying multiple objects in a single image remains a core challenge in the field, and we invest a significant amount of time training and experimenting with these systems. Detected objects in a sample image (from the COCO dataset) made by one of our models. Image credit: Michael Miley, original image.Last October, our in-house object detection system achieved new state-of-the-art results, and placed first in the COCO detection challenge. Since then, this system has generated results for a number of research publications1,2,3,4,5,6,7 and has been put to work in Google products such as NestCam, the similar items and style ideas feature in Image Search and street number and name detection in Street View.Today we are happy to make this system available to the broader research community via the TensorFlow Object Detection API. This codebase is an open-source framework built on top of TensorFlow that makes it easy to construct, train and deploy object detection models. Our goals in designing this system was to support state-of-the-art models while allowing for rapid exploration and research. Our first release contains the following:A selection of trainable detection models, including:Single Shot Multibox Detector (SSD) with MobileNetsSSD with Inception V2Region-Based Fully Convolutional Networks (R-FCN) with Resnet 101Faster RCNN with Resnet 101Faster RCNN with Inception Resnet v2Frozen weights (trained on the COCO dataset) for each of the above models to be used for out-of-the-box inference purposes.A Jupyter notebook for performing out-of-the-box inference with one of our released modelsConvenient local training scripts as well as distributed training and evaluation pipelines via Google CloudThe SSD models that use MobileNet are lightweight, so that they can be comfortably run in real time on mobile devices. Our winning COCO submission in 2016 used an ensemble of the Faster RCNN models, which are more computationally intensive but significantly more accurate. For more details on the performance of these models, see our CVPR 2017 paper.Are you ready to get started?We’ve certainly found this code to be useful for our computer vision needs, and we hope that you will as well. Contributions to the codebase are welcome and please stay tuned for our own further updates to the framework. To get started, download the code here and try detecting objects in some of your own images using the Jupyter notebook, or training your own pet detector on Cloud ML engine! AcknowledgementsThe release of the Tensorflow Object Detection API and the pre-trained model zoo has been the result of widespread collaboration among Google researchers with feedback and testing from product groups. In particular we want to highlight the contributions of the following individuals:Core Contributors: Derek Chow, Chen Sun, Menglong Zhu, Matthew Tang, Anoop Korattikara, Alireza Fathi, Ian Fischer, Zbigniew Wojna, Yang Song, Sergio Guadarrama, Jasper Uijlings, Viacheslav Kovalevskyi, Kevin MurphyAlso special thanks to: Andrew Howard, Rahul Sukthankar, Vittorio Ferrari, Tom Duerig, Chuck Rosenberg, Hartwig Adam, Jing Jing Long, Victor Gomes, George Papandreou, Tyler ZhuReferencesSpeed/accuracy trade-offs for modern convolutional object detectors, Huang et al., CVPR 2017 (paper describing this framework)Towards Accurate Multi-person Pose Estimation [...]



MobileNets: Open-Source Models for Efficient On-Device Vision

2017-06-19T17:14:36.088-07:00

Posted by Andrew G. Howard, Senior Software Engineer and Menglong Zhu, Software Engineer(Cross-posted on the Google Open Source Blog)Deep learning has fueled tremendous progress in the field of computer vision in recent years, with neural networks repeatedly pushing the frontier of visual recognition technology. While many of those technologies such as object, landmark, logo and text recognition are provided for internet-connected devices through the Cloud Vision API, we believe that the ever-increasing computational power of mobile devices can enable the delivery of these technologies into the hands of our users, anytime, anywhere, regardless of internet connection. However, visual recognition for on device and embedded applications poses many challenges — models must run quickly with high accuracy in a resource-constrained environment making use of limited computation, power and space. Today we are pleased to announce the release of MobileNets, a family of mobile-first computer vision models for TensorFlow, designed to effectively maximize accuracy while being mindful of the restricted resources for an on-device or embedded application. MobileNets are small, low-latency, low-power models parameterized to meet the resource constraints of a variety of use cases. They can be built upon for classification, detection, embeddings and segmentation similar to how other popular large scale models, such as Inception, are used. Example use cases include detection, fine-grain classification, attributes and geo-localization.This release contains the model definition for MobileNets in TensorFlow using TF-Slim, as well as 16 pre-trained ImageNet classification checkpoints for use in mobile projects of all sizes. The models can be run efficiently on mobile devices with TensorFlow Mobile. Model Checkpoint Million MACs Million Parameters Top-1 Accuracy Top-5 Accuracy MobileNet_v1_1.0_224 569 4.24 70.7 89.5 MobileNet_v1_1.0_192 418 4.24 69.3 88.9 MobileNet_v1_1.0_160 291 4.24 67.2 87.5 MobileNet_v1_1.0_128 186 4.24 64.1 85.3 MobileNet_v1_0.75_224 317 2.59 68.4 88.2 MobileNet_v1_0.75_192 233 2.59 67.4 87.3 MobileNet_v1_0.75_160 162 2.59 65.2 86.1 MobileNet_v1_0.75_128 104 2.59 61.8 83.6 MobileNet_v1_0.50_224 150 1.34 64.0 85.4 MobileNet_v1_0.50_192 110 1.34 62.1 84.0 MobileNet_v1_0.50_160 77 1.34 59.9 82.5 MobileNet_v1_0.50_128 49 1.34 56.2 79.6 MobileNet_v1_0.25_224 41 0.47 50.6 75.0 MobileNet_v1_0.25_192 34 0.47 49.0 73.6 MobileNet_v1_0.25_160 21 0.47 46.0 70.7 MobileNet_v1_0.25_128 14 0.47 41.3 66.2Choose the right MobileNet model to fit your latency and size budget. The size of the network in memory and on disk is proportional to the number of parameters. The latency and power usage of the network scales with the number of Multiply-Accumulates (MACs) which measures the number of fused Multiplication and Addition operations. Top-1 and Top-5 accuracies are measured on the ILSVRC dataset.We are excited to share MobileNets with the open-source community. Information for getting started can be found at the TensorFlow-Slim Image Classification Library. To learn how to run models on-device please go to TensorFlow Mobile. You can read more about the technical details of MobileNets in our paper, MobileNets: Efficient Convolutional Neural Networks for Mobile Vision Applications.AcknowledgementsMobileNets were made possible with the hard work of many engineers and researchers throughout Google. Specifically we would like to thank:Core Contributors: Andrew G. Howard, Menglong Zhu, Bo Chen, Dmitry Kalenichenko, Weijun Wang, Tobias Weyand, Marco Andreetto, Hartwig AdamSpecial thanks to: Benoit Jacob, Skirmantas Kligys, George Papandreou, Liang-Chieh Chen, Derek Chow, Sergio Guadarra[...]



The Machine Intelligence Behind Gboard

2017-05-24T13:52:26.564-07:00

Posted by Françoise Beaufays, Principal Scientist, Speech and Keyboard Team and Michael Riley, Principal Scientist, Speech and Languages Algorithms TeamMost people spend a significant amount of time each day using mobile-device keyboards: composing emails, texting, engaging in social media, and more. Yet, mobile keyboards are still cumbersome to handle. The average user is roughly 35% slower typing on a mobile device than on a physical keyboard. To change that, we recently provided many exciting improvements to Gboard for Android, working towards our vision of creating an intelligent mechanism that enables faster input while offering suggestions and correcting mistakes, in any language you choose. With the realization that the way a mobile keyboard translates touch inputs into text is similar to how a speech recognition system translates voice inputs into text, we leveraged our experience in Speech Recognition to pursue our vision. First, we created robust spatial models that map fuzzy sequences of raw touch points to keys on the keyboard, just like acoustic models map sequences of sound bites to phonetic units. Second, we built a powerful core decoding engine based on finite state transducers (FST) to determine the likeliest word sequence given an input touch sequence. With its mathematical formalism and broad success in speech applications, we knew that an FST decoder would offer the flexibility needed to support a variety of complex keyboard input behaviors as well as language features. In this post, we will detail what went into the development of both of these systems.Neural Spatial ModelsMobile keyboard input is subject to errors that are generally attributed to “fat finger typing” (or tracing spatially similar words in glide typing, as illustrated below) along with cognitive and motor errors (manifesting in misspellings, character insertions, deletions or swaps, etc). An intelligent keyboard needs to be able to account for these errors and predict the intended words rapidly and accurately. As such, we built a spatial model for Gboard that addresses these errors at the character level, mapping the touch points on the screen to actual keys.Average glide trails for two spatially-similar words: “Vampire” and “Value”.Up to recently, Gboard used a Gaussian model to quantify the probability of tapping neighboring keys and a rule-based model to represent cognitive and motor errors. These models were simple and intuitive, but they didn’t allow us to directly optimize metrics that correlate with better typing quality. Drawing on our experience with Voice Search acoustic models we replaced both the Gaussian and rule-based models with a single, highly efficient long short-term memory (LSTM) model trained with a connectionist temporal classification (CTC) criterion.However, training this model turned out to be a lot more complicated than we had anticipated. While acoustic models are trained from human-transcribed audio data, one cannot easily transcribe millions of touch point sequences and glide traces. So the team exploited user-interaction signals, e.g. reverted auto-corrections and suggestion picks as negative and positive semi-supervised learning signals, to form rich training and test sets. Raw data points corresponding to the word “could” (left), and normalized sampled trajectory with per-sample variances (right).A plethora of techniques from the speech recognition literature was used to iterate on the NSM models to make them small and fast enough to be run on any device. The TensorFlow infrastructure was used to train hundreds of models, optimizing various signals surfaced by the keyboard: completions, suggestions, gliding, [...]



Introducing the TensorFlow Research Cloud

2017-05-17T11:54:21.814-07:00

Posted by Zak Stone, Product Manager for TensorFlowResearchers require enormous computational resources to train the machine learning (ML) models that have delivered recent breakthroughs in medical imaging, neural machine translation, game playing, and many other domains. We believe that significantly larger amounts of computation will make it possible for researchers to invent new types of ML models that will be even more accurate and useful. To accelerate the pace of open machine-learning research, we are introducing the TensorFlow Research Cloud (TFRC), a cluster of 1,000 Cloud TPUs that will be made available free of charge to support a broad range of computationally-intensive research projects that might not be possible otherwise.The TensorFlow Research Cloud offers researchers the following benefits:Access to Google’s all-new Cloud TPUs that accelerate both training and inferenceUp to 180 teraflops of floating-point performance per Cloud TPU64 GB of ultra-high-bandwidth memory per Cloud TPUFamiliar TensorFlow programming interfacesYou can sign up here to request to be notified when the TensorFlow Research Cloud application process opens, and you can optionally share more information about your computational needs. We plan to evaluate applications on a rolling basis in search of the most creative and ambitious proposals.The TensorFlow Research Cloud program is not limited to academia — we recognize that people with a wide range of affiliations, roles, and expertise are making major machine learning research contributions, and we especially encourage those with non-traditional backgrounds to apply. Access will be granted to selected individuals for limited amounts of compute time, and researchers are welcome to apply multiple times with multiple projects.Since the main goal of the TensorFlow Research Cloud is to benefit the open machine learning research community as a whole, successful applicants will be expected to do the following:Share their TFRC-supported research with the world through peer-reviewed publications, open-source code, blog posts, or other open mediaShare concrete, constructive feedback with Google to help us improve the TFRC program and the underlying Cloud TPU platform over timeImagine a future in which ML acceleration is abundant and develop new kinds of machine learning models in anticipation of that futureFor businesses interested in using Cloud TPUs for proprietary research and development, we will offer a parallel Cloud TPU Alpha program. You can sign up here to learn more about this program. We recommend participating in the Cloud TPU Alpha program if you are interested in any of the following:Accelerating training of proprietary ML models; models that take weeks to train on other hardware can be trained in days or even hours on Cloud TPUsAccelerating batch processing of industrial-scale datasets: images, videos, audio, unstructured text, structured data, etc.Processing live requests in production using larger and more complex ML models than ever beforeWe hope the TensorFlow Research Cloud will allow as many researchers as possible to explore the frontier of machine learning research and extend it with new discoveries! We encourage you to sign up today to be among the first to know as more information becomes available. [...]



Using Machine Learning to Explore Neural Network Architecture

2017-05-17T10:40:59.829-07:00

Posted by Quoc Le & Barret Zoph, Research Scientists, Google Brain teamAt Google, we have successfully applied deep learning models to many applications, from image recognition to speech recognition to machine translation. Typically, our machine learning models are painstakingly designed by a team of engineers and scientists. This process of manually designing machine learning models is difficult because the search space of all possible models can be combinatorially large — a typical 10-layer network can have ~1010 candidate networks! For this reason, the process of designing networks often takes a significant amount of time and experimentation by those with significant machine learning expertise. Our GoogleNet architecture. Design of this network required many years of careful experimentation and refinement from initial versions of convolutional architectures.To make this process of designing machine learning models much more accessible, we’ve been exploring ways to automate the design of machine learning models. Among many algorithms we’ve studied, evolutionary algorithms [1] and reinforcement learning algorithms [2] have shown great promise. But in this blog post, we’ll focus on our reinforcement learning approach and the early results we’ve gotten so far.In our approach (which we call "AutoML"), a controller neural net can propose a “child” model architecture, which can then be trained and evaluated for quality on a particular task. That feedback is then used to inform the controller how to improve its proposals for the next round. We repeat this process thousands of times — generating new architectures, testing them, and giving that feedback to the controller to learn from. Eventually the controller learns to assign high probability to areas of architecture space that achieve better accuracy on a held-out validation dataset, and low probability to areas of architecture space that score poorly. Here’s what the process looks like:We’ve applied this approach to two heavily benchmarked datasets in deep learning: image recognition with CIFAR-10 and language modeling with Penn Treebank. On both datasets, our approach can design models that achieve accuracies on par with state-of-art models designed by machine learning experts (including some on our own team!).So, what kind of neural nets does it produce? Let’s take one example: a recurrent architecture that’s trained to predict the next word on the Penn Treebank dataset. On the left here is a neural net designed by human experts. On the right is a recurrent architecture created by our method: The machine-chosen architecture does share some common features with the human design, such as using addition to combine input and previous hidden states. However, there are some notable new elements — for example, the machine-chosen architecture incorporates a multiplicative combination (the left-most blue node on the right diagram labeled “elem_mult”). This type of combination is not common for recurrent networks, perhaps because researchers see no obvious benefit for having it. Interestingly, a simpler form of this approach was recently suggested by human designers, who also argued that this multiplicative combination can actually alleviate gradient vanishing/exploding issues, suggesting that the machine-chosen architecture was able to discover a useful new neural net architecture.This approach may also teach us something about why certain types of neural nets work so well. The architecture on the right here has many channels so that the gradient can flow backwards, which may help explain why LSTM RNNs work better tha[...]



Efficient Smart Reply, now for Gmail

2017-05-17T10:11:15.452-07:00

Posted by Brian Strope, Research Scientist, and Ray Kurzweil, Engineering Director, Google ResearchLast year we launched Smart Reply, a feature for Inbox by Gmail that uses machine learning to suggest replies to email. Since the initial release, usage of Smart Reply has grown significantly, making up about 12% of replies in Inbox on mobile. Based on our examination of the use of Smart Reply in Inbox and our ideas about how humans learn and use language, we have created a new version of Smart Reply for Gmail. This version increases the percentage of usable suggestions and is more algorithmically efficient. Novel thinking: hierarchyInspired by how humans understand languages and concepts, we turned to hierarchical models of language, an approach that uses hierarchies of modules, each of which can learn, remember, and recognize a sequential pattern. The content of language is deeply hierarchical, reflected in the structure of language itself, going from letters to words to phrases to sentences to paragraphs to sections to chapters to books to authors to libraries, etc. Consider the message, "That interesting person at the cafe we like gave me a glance." The hierarchical chunks in this sentence are highly variable. The subject of the sentence is "That interesting person at the cafe we like." The modifier "interesting" tells us something about the writer's past experiences with the person. We are told that the location of an incident involving both the writer and the person is "at the cafe." We are also told that "we," meaning the writer and the person being written to, like the cafe. Additionally, each word is itself part of a hierarchy, sometimes more than one. A cafe is a type of restaurant which is a type of store which is a type of establishment, and so on. In proposing an appropriate response to this message we might consider the meaning of the word "glance," which is potentially ambiguous. Was it a positive gesture? In that case, we might respond, "Cool!" Or was it a negative gesture? If so, does the subject say anything about how the writer felt about the negative exchange? A lot of information about the world, and an ability to make reasoned judgments, are needed to make subtle distinctions.Given enough examples of language, a machine learning approach can discover many of these subtle distinctions. Moreover, a hierarchical approach to learning is well suited to the hierarchical nature of language. We have found that this approach works well for suggesting possible responses to emails. We use a hierarchy of modules, each of which considers features that correspond to sequences at different temporal scales, similar to how we understand speech and language. Each module processes inputs and provides transformed representations of those inputs on its outputs (which are, in turn, available for the next level). In the Smart Reply system, and the figure above, the repeated structure has two layers of hierarchy. The first makes each feature useful as a predictor of the final result, and the second combines these features. By definition, the second works at a more abstract representation and considers a wider timescale.By comparison, the initial release of Smart Reply encoded input emails word-by-word with a long-short-term-memory (LSTM) recurrent neural network, and then decoded potential replies with yet another word-level LSTM. While this type of modeling is very effective in many contexts, even with Google infrastructure, it’s an approach that requires substantial computation resources. Instead of working word-by-word, we found an effective and highly efficient [...]



Coarse Discourse: A Dataset for Understanding Online Discussions

2017-05-16T11:00:24.864-07:00

Posted by Praveen Paritosh, Senior Research Scientist, Ka Wong, Senior Data ScientistEvery day, participants of online communities form and share their opinions, experiences, advice and social support, most of which is expressed freely and without much constraint. These online discussions are often a key resource of information for many important topics, such as parenting, fitness, travel and more. However, these discussions also are intermixed with a clutter of disagreements, humor, flame wars and trolling, requiring readers to filter the content before getting the information they are looking for. And while the field of Information Retrieval actively explores ways to allow users to more efficiently find, navigate and consume this content, there is a lack of shared datasets on forum discussions to aid in understanding these discussions a bit better. To aid researchers in this space, we are releasing the Coarse Discourse dataset, the largest dataset of annotated online discussions to date. The Coarse Discourse contains over half a million human annotations of publicly available online discussions on a random sample of over 9,000 threads from 130 communities from reddit.com. To create this dataset, we developed the Coarse Discourse taxonomy of forum comments by going through a small set of forum threads, reading every comment, and deciding what role the comments played in the discussion. We then repeated and revised this exercise with crowdsourced human editors to validate the reproducibility of the taxonomy's discourse types, which include: announcement, question, answer, agreement, disagreement, appreciation, negative reaction, elaboration, and humor. From this data, over 100,000 comments were independently annotated by the crowdsourced editors for discourse type and relation. Along with the raw annotations from crowdsourced editors, we also provide the Coarse Discourse annotation task guidelines used by the editors to help with collecting data for other forums and refining the task further. An example thread annotated with discourse types and relations. Early findings suggest that question answering is a prominent use case in most communities, while some communities are more converationally focused, with back-and-forth interactions. For machine learning and natural language processing researchers trying to characterize the nature of online discussions, we hope that this dataset is a useful resource. Visit our GitHub repository to download the data. For more details, check out our ICWSM paper, “Characterizing Online Discussion Using Coarse Discourse Sequences.”AcknowledgmentsThis work was done by Amy Zhang during her internship at Google. We would also like to thank Bryan Culbertson, Olivia Rhinehart, Eric Altendorf, David Huynh, Nancy Chang, Chris Welty and our crowdsourced editors. [...]



Neural Network-Generated Illustrations in Allo

2017-05-11T09:28:35.532-07:00

Posted by Jennifer Daniel, Expressions Creative Director, Allo Taking, sharing, and viewing selfies has become a daily habit for many — the car selfie, the cute-outfit selfie, the travel selfie, the I-woke-up-like-this selfie. Apart from a social capacity, self-portraiture has long served as a means for self and identity exploration. For some, it’s about figuring out who they are. For others it’s about projecting how they want to be perceived. Sometimes it’s both.Photography in the form of a selfie is a very direct form of expression. It comes with a set of rules bounded by reality. Illustration, on the other hand, empowers people to define themselves - it’s warmer and less fraught than reality. Today, Google is introducing a feature in Allo that uses a combination of neural networks and the work of artists to turn your selfie into a personalized sticker pack. Simply snap a selfie, and it’ll return an automatically generated illustrated version of you, on the fly, with customization options to help you personalize the stickers even further.What makes you, you?The traditional computer vision approach to mapping selfies to art would be to analyze the pixels of an image and algorithmically determine attribute values by looking at pixel values to measure color, shape, or texture. However, people today take selfies in all types of lighting conditions and poses. And while people can easily pick out and recognize qualitative features, like eye color, regardless of the lighting condition, this is a very complex task for computers. When people look at eye color, they don’t just interpret the pixel values of blue or green, but take into account the surrounding visual context.In order to account for this, we explored how we could enable an algorithm to pick out qualitative features in a manner similar to the way people do, rather than the traditional approach of hand coding how to interpret every permutation of lighting condition, eye color, etc. While we could have trained a large convolutional neural network from scratch to attempt to accomplish this, we wondered if there was a more efficient way to get results, since we expected that learning to interpret a face into an illustration would be a very iterative process. That led us to run some experiments, similar to DeepDream, on some of Google's existing more general-purpose computer vision neural networks. We discovered that a few neurons among the millions in these networks were good at focusing on things they weren’t explicitly trained to look at that seemed useful for creating personalized stickers. Additionally, by virtue of being large general-purpose neural networks they had already figured out how to abstract away things they didn’t need. All that was left to do was to provide a much smaller number of human labeled examples to teach the classifiers to isolate out the qualities that the neural network already knew about the image.To create an illustration of you that captures the qualities that would make it recognizable to your friends, we worked alongside an artistic team to create illustrations that represented a wide variety of features. Artists initially designed a set of hairstyles, for example, that they thought would be representative, and with the help of human raters we used these hairstyles to train the network to match the right illustration to the right selfie. We then asked human raters to judge the sticker output against the input image to see how well it did. In some instances, they determined that some styles were not well repres[...]



Updating Google Maps with Deep Learning and Street View

2017-05-03T17:50:12.813-07:00

Posted by Julian Ibarz, Staff Software Engineer, Google Brain Team and Sujoy Banerjee, Product Manager, Ground Truth TeamEvery day, Google Maps provides useful directions, real-time traffic information and information on businesses to millions of people. In order to provide the best experience for our users, this information has to constantly mirror an ever-changing world. While Street View cars collect millions of images daily, it is impossible to manually analyze more than 80 billion high resolution images collected to date in order to find new, or updated, information for Google Maps. One of the goals of the Google’s Ground Truth team is to enable the automatic extraction of information from our geo-located imagery to improve Google Maps.In “Attention-based Extraction of Structured Information from Street View Imagery”, we describe our approach to accurately read street names out of very challenging Street View images in many countries, automatically, using a deep neural network. Our algorithm achieves 84.2% accuracy on the challenging French Street Name Signs (FSNS) dataset, significantly outperforming the previous state-of-the-art systems. Importantly, our system is easily extensible to extract other types of information out of Street View images as well, and now helps us automatically extract business names from store fronts. We are excited to announce that this model is now publicly available!Example of street name from the FSNS dataset correctly transcribed by our system. Up to four views of the same sign are provided.Text recognition in a natural environment is a challenging computer vision and machine learning problem. While traditional Optical Character Recognition (OCR) systems mainly focus on extracting text from scanned documents, text acquired from natural scenes is more challenging due to visual artifacts, such as distortion, occlusions, directional blur, cluttered background or different viewpoints. Our efforts to solve this research challenge first began in 2008, when we used neural networks to blur faces and license plates in Street View images to protect the privacy of our users. From this initial research, we realized that with enough labeled data, we could additionally use machine learning not only to protect the privacy of our users, but also to automatically improve Google Maps with relevant up-to-date information.In 2014, Google’s Ground Truth team published a state-of-the-art method for reading street numbers on the Street View House Numbers (SVHN) dataset, implemented by then summer intern (now Googler) Ian Goodfellow. This work was not only of academic interest but was critical in making Google Maps more accurate. Today, over one-third of addresses globally have had their location improved thanks to this system. In some countries, such as Brazil, this algorithm has improved more than 90% of the addresses in Google Maps today, greatly improving the usability of our maps.The next logical step was to extend these techniques to street names. To solve this problem, we created and released French Street Name Signs (FSNS), a large training dataset of more than 1 million street names. The FSNS dataset was a multi-year effort designed to allow anyone to improve their OCR models on a challenging and real use case. FSNS dataset is much larger and more challenging than SVHN in that accurate recognition of street signs may require combining information from many different images.These are examples of challenging signs that are properly transcribed by our system [...]



Experimental Nighttime Photography with Nexus and Pixel

2017-04-25T09:00:00.153-07:00

Posted by Florian Kainz, Software Engineer, Google DaydreamOn a full moon night last year I carried a professional DSLR camera, a heavy lens and a tripod up to a hilltop in the Marin Headlands just north of San Francisco to take a picture of the Golden Gate Bridge and the lights of the city behind it. A view of the Golden Gate Bridge from the Marin Headlands, taken with a DSLR camera (Canon 1DX, Zeiss Otus 28mm f/1.4 ZE). Click here for the full resolution image.I thought the photo of the moonlit landscape came out well so I showed it to my (then) teammates in Gcam, a Google Research team that focuses on computational photography - developing algorithms that assist in taking pictures, usually with smartphones and similar small cameras. Seeing my nighttime photo, one of the Gcam team members challenged me to re-take it, but with a phone camera instead of a DSLR. Even though cameras on cellphones have come a long way, I wasn’t sure whether it would be possible to come close to the DSLR shot.Probably the most successful Gcam project to date is the image processing pipeline that enables the HDR+ mode in the camera app on Nexus and Pixel phones. HDR+ allows you to take photos at low-light levels by rapidly shooting a burst of up to ten short exposures and averaging them them into a single image, reducing blur due to camera shake while collecting enough total light to yield surprisingly good pictures. Of course there are limits to what HDR+ can do. Once it gets dark enough the camera just cannot gather enough light and challenging shots like nighttime landscapes are still beyond reach. The ChallengesTo learn what was possible with a cellphone camera in extremely low-light conditions, I looked to the experimental SeeInTheDark app, written by Marc Levoy and presented at the ICCV 2015 Extreme Imaging Workshop, which can produce pictures with even less light than HDR+. It does this by accumulating more exposures, and merging them under the assumption that the scene is static and any differences between successive exposures must be due to camera motion or sensor noise. The app reduces noise further by dropping image resolution to about 1 MPixel. With SeeInTheDark it is just possible to take pictures, albeit fairly grainy ones, by the light of the full moon.However, in order to keep motion blur due to camera shake and moving objects in the scene at acceptable levels, both HDR+ and SeeInTheDark must keep the exposure times for individual frames below roughly one tenth of a second. Since the user can’t hold the camera perfectly still for extended periods, it doesn’t make sense to attempt to merge a large number of frames into a single picture. Therefore, HDR+ merges at most ten frames, while SeeInTheDark progressively discounts older frames as new ones are captured. This limits how much light the camera can gather and thus affects the quality of the final pictures at very low light levels.Of course, if we want to take high-quality pictures of low-light scenes (such as a landscape illuminated only by the moon), increasing the exposure time to more than one second and mounting the phone on a tripod or placing it on some other solid support makes the task a lot easier. Google’s Nexus 6P and Pixel phones support exposure times of 4 and 2 seconds respectively. As long as the scene is static, we should be able to record and merge dozens of frames to produce a single final image, even if shooting those frames takes several minutes.Even with the use of a tripod, a sharp p[...]



Research at Google and ICLR 2017

2017-07-05T15:21:00.628-07:00

Posted by Ian Goodfellow, Staff Research Scientist, Google Brain Team This week, Toulon, France hosts the 5th International Conference on Learning Representations (ICLR 2017), a conference focused on how one can learn meaningful and useful representations of data for Machine Learning. ICLR includes conference and workshop tracks, with invited talks along with oral and poster presentations of some of the latest research on deep learning, metric learning, kernel learning, compositional models, non-linear structured prediction, and issues regarding non-convex optimization.At the forefront of innovation in cutting-edge technology in Neural Networks and Deep Learning, Google focuses on both theory and application, developing learning approaches to understand and generalize. As Platinum Sponsor of ICLR 2017, Google will have a strong presence with over 50 researchers attending (many from the Google Brain team and Google Research Europe), contributing to and learning from the broader academic research community by presenting papers and posters, in addition to participating on organizing committees and in workshops.If you are attending ICLR 2017, we hope you'll stop by our booth and chat with our researchers about the projects and opportunities at Google that go into solving interesting problems for billions of people. You can also learn more about our research being presented at ICLR 2017 in the list below (Googlers highlighted in blue).Area Chairs include:George Dahl, Slav Petrov, Vikas SindhwaniProgram Chairs include:Hugo Larochelle, Tara SainathContributed TalksUnderstanding Deep Learning Requires Rethinking Generalization (Best Paper Award)Chiyuan Zhang*, Samy Bengio, Moritz Hardt, Benjamin Recht*, Oriol VinyalsSemi-Supervised Knowledge Transfer for Deep Learning from Private Training Data (Best Paper Award)Nicolas Papernot*, Martín Abadi, Úlfar Erlingsson, Ian Goodfellow, KunalTalwarQ-Prop: Sample-Efficient Policy Gradient with An Off-Policy CriticShixiang (Shane) Gu*, Timothy Lillicrap, Zoubin Ghahramani, Richard E.Turner, Sergey LevineNeural Architecture Search with Reinforcement LearningBarret Zoph, Quoc LePostersAdversarial Machine Learning at ScaleAlexey Kurakin, Ian J. Goodfellow†, Samy BengioCapacity and Trainability in Recurrent Neural NetworksJasmine Collins, Jascha Sohl-Dickstein, David SussilloImproving Policy Gradient by Exploring Under-Appreciated RewardsOfir Nachum, Mohammad Norouzi, Dale SchuurmansOutrageously Large Neural Networks: The Sparsely-Gated Mixture-of-Experts LayerNoam Shazeer, Azalia Mirhoseini, Krzysztof Maziarz, Andy Davis, Quoc Le, Geoffrey Hinton, Jeff DeanUnrolled Generative Adversarial NetworksLuke Metz, Ben Poole*, David Pfau, Jascha Sohl-DicksteinCategorical Reparameterization with Gumbel-SoftmaxEric Jang, Shixiang (Shane) Gu*, Ben Poole*Decomposing Motion and Content for Natural Video Sequence PredictionRuben Villegas, Jimei Yang, Seunghoon Hong, Xunyu Lin, Honglak LeeDensity Estimation Using Real NVPLaurent Dinh*, Jascha Sohl-Dickstein, Samy BengioLatent Sequence DecompositionsWilliam Chan*, Yu Zhang*, Quoc Le, Navdeep Jaitly*Learning a Natural Language Interface with Neural ProgrammerArvind Neelakantan*, Quoc V. Le, Martín Abadi, Andrew McCallum*, Dario Amodei*Deep Information PropagationSamuel Schoenholz, Justin Gilmer, Surya Ganguli, Jascha Sohl-DicksteinIdentity Matters in Deep LearningMoritz Hardt, Tengy[...]



PhotoScan: Taking Glare-Free Pictures of Pictures

2017-04-20T10:42:50.233-07:00

Posted by Ce Liu, Michael Rubinstein, Mike Krainin and Bill Freeman, Research ScientistsYesterday, we released an update to PhotoScan, an app for iOS and Android that allows you to digitize photo prints with just a smartphone. One of the key features of PhotoScan is the ability to remove glare from prints, which are often glossy and reflective, as are the plastic album pages or glass-covered picture frames that host them. To create this feature, we developed a unique blend of computer vision and image processing techniques that can carefully align and combine several slightly different pictures of a print to separate the glare from the image underneath.Left: A regular digital picture of a physical print. Right: Glare-free digital output from PhotoScanWhen taking a single picture of a photo, determining which regions of the picture are the actual photo and which regions are glare is challenging to do automatically. Moreover, the glare may often saturate regions in the picture, rendering it impossible to see or recover the parts of the photo underneath it. But if we take several pictures of the photo while moving the camera, the position of the glare tends to change, covering different regions of the photo. In most cases we found that every pixel of the photo is likely not to be covered by glare in at least one of the pictures. While no single view may be glare-free, we can combine multiple pictures of the printed photo taken at different angles to remove the glare. The challenge is that the images need to be aligned very accurately in order to combine them properly, and this processing needs to run very quickly on the phone to provide a near instant experience. Left: The captured, input images (5 in total). Right: If we stabilize the images on the photo, we can see just the glare moving, covering different parts of the photo. Notice no single image is glare-free.Our technique is inspired by our earlier work published at SIGGRAPH 2015, which we dubbed “obstruction-free photography”. It uses similar principles to remove various types of obstructions from the field of view. However, the algorithm we originally proposed was based on a generative model where the motion and appearance of both the main scene and the obstruction layer are estimated. While that model is quite powerful and can remove a variety of obstructions, it is too computationally expensive to be run on smartphones. We therefore developed a simpler model that treats glare as an outlier, and only attempts to register the underlying, glare-free photo. While this model is simpler, the task is still quite challenging as the registration needs to be highly accurate and robust.How it WorksWe start from a series of pictures of the print taken by the user while moving the camera. The first picture - the “reference frame” - defines the desired output viewpoint. The user is then instructed to take four additional frames. In each additional frame, we detect sparse feature points (we compute ORB features on Harris corners) and use them to establish homographies mapping each frame to the reference frame.Left: Detected feature matches between the reference frame and each other frame (left), and the warped frames according to the estimated homographies (right).While the technique may sound straightforward, there is a catch - homographies are only able to align flat images. But printed photos are often not entirely flat (as is the case with the ex[...]



Teaching Machines to Draw

2017-04-13T16:37:04.126-07:00

Posted by David Ha, Google Brain ResidentAbstract visual communication is a key part of how people convey ideas to one another. From a young age, children develop the ability to depict objects, and arguably even emotions, with only a few pen strokes. These simple drawings may not resemble reality as captured by a photograph, but they do tell us something about how people represent and reconstruct images of the world around them.Vector drawings produced by sketch-rnn.In our recent paper, “A Neural Representation of Sketch Drawings”, we present a generative recurrent neural network capable of producing sketches of common objects, with the goal of training a machine to draw and generalize abstract concepts in a manner similar to humans. We train our model on a dataset of hand-drawn sketches, each represented as a sequence of motor actions controlling a pen: which direction to move, when to lift the pen up, and when to stop drawing. In doing so, we created a model that potentially has many applications, from assisting the creative process of an artist, to helping teach students how to draw.While there is a already a large body of existing work on generative modelling of images using neural networks, most of the work focuses on modelling raster images represented as a 2D grid of pixels. While these models are currently able to generate realistic images, due to the high dimensionality of a 2D grid of pixels, a key challenge for them is to generate images with coherent structure. For example, these models sometimes produce amusing images of cats with three or more eyes, or dogs with multiple heads.Examples of animals generated with the wrong number of body parts, produced using previous GAN models trained on 128x128 ImageNet dataset. The image above is Figure 29 ofGenerative Adversarial Networks, Ian Goodfellow, NIPS 2016 Tutorial.In this work, we investigate a lower-dimensional vector-based representation inspired by how people draw. Our model, sketch-rnn, is based on the sequence-to-sequence (seq2seq) autoencoder framework. It incorporates variational inference and utilizes hypernetworks as recurrent neural network cells. The goal of a seq2seq autoencoder is to train a network to encode an input sequence into a vector of floating point numbers, called a latent vector, and from this latent vector reconstruct an output sequence using a decoder that replicates the input sequence as closely as possible.Schematic of sketch-rnn.In our model, we deliberately add noise to the latent vector. In our paper, we show that by inducing noise into the communication channel between the encoder and the decoder, the model is no longer be able to reproduce the input sketch exactly, but instead must learn to capture the essence of the sketch as a noisy latent vector. Our decoder takes this latent vector and produces a sequence of motor actions used to construct a new sketch. In the figure below, we feed several actual sketches of cats into the encoder to produce reconstructed sketches using the decoder.Reconstructions from a model trained on cat sketches.It is important to emphasize that the reconstructed cat sketches are not copies of the input sketches, but are instead new sketches of cats with similar characteristics as the inputs. To demonstrate that the model is not simply copying from the input sequence, and that it actually learned something about the way people draw cats, we can try to feed [...]