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Misc

HELP!! How do I explain the Maths behind Human Pose Estimation?

Okay, I feel like this is such a dumb question but please please help me. I’m a high school student and I really really want to do this my Maths written assessment on human pose estimation because I want to analyze/accurately compare my dance covers to the original dancer’s performance. I got my inspiration from this video: https://www.youtube.com/watch?v=bPDoMdn71h0&t=0s

I’m really keen to do this and explain the mathematics behind this because I have such a deep interest in it but I honestly don’t know where to start!

Like what should I do? Vectors? Matrices? Gradients? Geometry? Trig? Please help!!!!

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Misc

Keras weights contraints including both bias and kernel matrix at the same time

Hi everyone, I have a question posted on stackoverflow but wanted to share it here too in case someone can help:

My question is related with how keras implements the weights constraints, in particular in dense layers. I am using mainly R and its keras implementation, so I will use here their notation, but I will be also happy if someone has a solution in Python. As far as I know, keras constraints like constraint_maxnorm() can be applied to a layer_dense() with the arguments kernel_constraint or bias_constraint, where the kernel refers to the weigth matrix without the bias terms. However, in order to test new approaches I think it would be useful to also be able to apply constraints to the full weight matrix, where the biases vector forms an extra row in the weigth matrix. An example of this kind of constraint would be to restrict to 1 the L1 norm of the weight vectors incident to a neuron (considering the bias at that neuron also as an element of said vector).

In this sense, custom constraints can be created but the problem is that they receive the kernel weights as input, not both the kernel weights and bias, and the output is also only the kernel weights, not the full weight matrix.

Is it possible to implement this kind of constraints in keras or tensorflow that affect both the kernel and the bias at the same time? In this sense, it would be enough to be able to create custom constraints that accept both the kernel weights and the bias as input, and then apply the desired constraint twice, at the kernel and at the bias.

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Misc

Will the tensorflow developer certificate help me get an internship?

Will the tensorflow developer certificate help me get an internship?

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Misc

Constellation detection

I need to detect the Big Dipper constelation on photos of night sky. Is Tensorflow good choice for this kind of project? How can I start with it?

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Misc

Learn More About Reservoir Sampling in Free Ray Tracing Gems II Chapter

As the August 4 release date for Ray Tracing Gems II nears, NVIDIA is offering another free chapter from the book to celebrate. This time, the topic is reservoir sampling, which is a family of algorithms that, given a stream of N elements, randomly select a K-element subset in a single pass. Usually, K is defined as a small constant, but N need not be known in advance. 

As the August 4 release date for Ray Tracing Gems II nears, NVIDIA is offering another free chapter from the book to celebrate. This time, the topic is reservoir sampling, which is a family of algorithms that, given a stream of N elements, randomly select a K-element subset in a single pass. Usually, K is defined as a small constant, but N need not be known in advance. 

This powerful gem is a foundational tool as real-time ray tracing becomes ubiquitous. Examples of reservoir sampling in action include stochastic transparency and importance sampling techniques unlocking the ability to effectively sample millions of lights within a real-time budget. You can download the full chapter free here. 

Just like the first book, the digital edition of Ray Tracing Gems II will be free to download and the print edition will be available for purchase from Apress and Amazon.

We’ve collaborated with our partners to make four limited edition versions of the book, including custom covers that highlight real-time ray tracing in Fortnite, Control, Watch Dogs: Legion, and Quake II RTX.

To win a limited edition print copy of Ray Tracing Gems II, enter the giveaway contest here: https://developer.nvidia.com/ray-tracing-gems-ii

Categories
Offsites

Why aren’t you making math videos? (Also, now there’s a 3b1b podcast)

Categories
Offsites

High Fidelity Image Generation Using Diffusion Models

Posted by Jonathan Ho, Research Scientist and Chitwan Saharia, Software Engineer, Google Research, Brain Team

Natural image synthesis is a broad class of machine learning (ML) tasks with wide-ranging applications that pose a number of design challenges. One example is image super-resolution, in which a model is trained to transform a low resolution image into a detailed high resolution image (e.g., RAISR). Super-resolution has many applications that can range from restoring old family portraits to improving medical imaging systems. Another such image synthesis task is class-conditional image generation, in which a model is trained to generate a sample image from an input class label. The resulting generated sample images can be used to improve performance of downstream models for image classification, segmentation, and more.

Generally, these image synthesis tasks are performed by deep generative models, such as GANs, VAEs, and autoregressive models. Yet each of these generative models has its downsides when trained to synthesize high quality samples on difficult, high resolution datasets. For example, GANs often suffer from unstable training and mode collapse, and autoregressive models typically suffer from slow synthesis speed.

Alternatively, diffusion models, originally proposed in 2015, have seen a recent revival in interest due to their training stability and their promising sample quality results on image and audio generation. Thus, they offer potentially favorable trade-offs compared to other types of deep generative models. Diffusion models work by corrupting the training data by progressively adding Gaussian noise, slowly wiping out details in the data until it becomes pure noise, and then training a neural network to reverse this corruption process. Running this reversed corruption process synthesizes data from pure noise by gradually denoising it until a clean sample is produced. This synthesis procedure can be interpreted as an optimization algorithm that follows the gradient of the data density to produce likely samples.

Today we present two connected approaches that push the boundaries of the image synthesis quality for diffusion models — Super-Resolution via Repeated Refinements (SR3) and a model for class-conditioned synthesis, called Cascaded Diffusion Models (CDM). We show that by scaling up diffusion models and with carefully selected data augmentation techniques, we can outperform existing approaches. Specifically, SR3 attains strong image super-resolution results that surpass GANs in human evaluations. CDM generates high fidelity ImageNet samples that surpass BigGAN-deep and VQ-VAE2 on both FID score and Classification Accuracy Score by a large margin.

SR3: Image Super-Resolution
SR3 is a super-resolution diffusion model that takes as input a low-resolution image, and builds a corresponding high resolution image from pure noise. The model is trained on an image corruption process in which noise is progressively added to a high-resolution image until only pure noise remains. It then learns to reverse this process, beginning from pure noise and progressively removing noise to reach a target distribution through the guidance of the input low-resolution image..

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With large scale training, SR3 achieves strong benchmark results on the super-resolution task for face and natural images when scaling to resolutions 4x–8x that of the input low-resolution image. These super-resolution models can further be cascaded together to increase the effective super-resolution scale factor, e.g., stacking a 64×64 → 256×256 and a 256×256 → 1024×1024 face super-resolution model together in order to perform a 64×64 → 1024×1024 super-resolution task.

We compare SR3 with existing methods using human evaluation study. We conduct a Two-Alternative Forced Choice Experiment where subjects are asked to choose between the reference high resolution image, and the model output when asked the question, “Which image would you guess is from a camera?” We measure the performance of the model through confusion rates (% of time raters choose the model outputs over reference images, where a perfect algorithm would achieve a 50% confusion rate). The results of this study are shown in the figure below.

Above: We achieve close to 50% confusion rate on the task of 16×16 → 128×128 faces, outperforming state-of-the-art face super-resolution methods PULSE and FSRGAN. Below: We also achieve a 40% confusion rate on the much more difficult task of 64×64 → 256×256 natural images, outperforming the regression baseline by a large margin.

CDM: Class-Conditional ImageNet Generation
Having shown the effectiveness of SR3 in performing natural image super-resolution, we go a step further and use these SR3 models for class-conditional image generation. CDM is a class-conditional diffusion model trained on ImageNet data to generate high-resolution natural images. Since ImageNet is a difficult, high-entropy dataset, we built CDM as a cascade of multiple diffusion models. This cascade approach involves chaining together multiple generative models over several spatial resolutions: one diffusion model that generates data at a low resolution, followed by a sequence of SR3 super-resolution diffusion models that gradually increase the resolution of the generated image to the highest resolution. It is well known that cascading improves quality and training speed for high resolution data, as shown by previous studies (for example in autoregressive models and VQ-VAE-2) and in concurrent work for diffusion models. As demonstrated by our quantitative results below, CDM further highlights the effectiveness of cascading in diffusion models for sample quality and usefulness in downstream tasks, such as image classification.

Example of the cascading pipeline that includes a sequence of diffusion models: the first generates a low resolution image, and the rest perform upsampling to the final high resolution image. Here the pipeline is for class-conditional ImageNet generation, which begins with a class-conditional diffusion model at 32×32 resolution, followed by 2x and 4x class-conditional super-resolution using SR3.
Selected generated images from our 256×256 cascaded class-conditional ImageNet model.

Along with including the SR3 model in the cascading pipeline, we also introduce a new data augmentation technique, which we call conditioning augmentation, that further improves the sample quality results of CDM. While the super-resolution models in CDM are trained on original images from the dataset, during generation they need to perform super-resolution on the images generated by a low-resolution base model, which may not be of sufficiently high quality in comparison to the original images. This leads to a train-test mismatch for the super-resolution models. Conditioning augmentation refers to applying data augmentation to the low-resolution input image of each super-resolution model in the cascading pipeline. These augmentations, which in our case include Gaussian noise and Gaussian blur, prevents each super-resolution model from overfitting to its lower resolution conditioning input, eventually leading to better higher resolution sample quality for CDM.

Altogether, CDM generates high fidelity samples superior to BigGAN-deep and VQ-VAE-2 in terms of both FID score and Classification Accuracy Score on class-conditional ImageNet generation. CDM is a pure generative model that does not use a classifier to boost sample quality, unlike other models such as ADM and VQ-VAE-2. See below for quantitative results on sample quality.

Class-conditional ImageNet FID scores at the 256×256 resolution for methods that do not use extra classifiers to boost sample quality. BigGAN-deep is reported at its best truncation value. (Lower is better.)
ImageNet classification accuracy scores at the 256×256 resolution, measuring the validation set accuracy of a classifier trained on generated data. CDM generated data attains significant gains over existing methods, closing the gap in classification accuracy between real and generated data. (Higher is better.)

Conclusion
With SR3 and CDM, we have pushed the performance of diffusion models to state-of-the-art on super-resolution and class-conditional ImageNet generation benchmarks. We are excited to further test the limits of diffusion models for a wide variety of generative modeling problems. For more information on our work, please visit Image Super-Resolution via Iterative Refinement and Cascaded Diffusion Models for High Fidelity Image Generation.

Acknowledgements:
We thank our co-authors William Chan, Mohammad Norouzi, Tim Salimans, and David Fleet, and we are grateful for research discussions and assistance from Ben Poole, Jascha Sohl-Dickstein, Doug Eck, and the rest of the Google Research, Brain Team.

Categories
Misc

Tensorflow-gpu

Tensorflow-gpu

Hello, when i’m installing tensorflow-gpu=2.3, i get this error. Anyone know this error please help me! I installed CUDA toolkit version 10.1. Thanks

https://preview.redd.it/0lne7mnpshb71.png?width=1366&format=png&auto=webp&s=d681c5ba38a095e9249be5cdde10c1b4b90e066e

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Misc

Network Guesses Very Similar For All Inputs

I have an image classification neural network that is designed for multi-label classification, I am using multi-hot encoded data, and a data generator that reads image files off of my hard drive. all images have been resized into the range of 96×96 (keeping aspect ratio (Also I have the same data in many other sizes)), and all color values have been divided by 255, although I have thought of switching that to 127.5 and then subtract 1. my learning algorithm is Adam with a learning rate of 0.0001. I am using binary crossentropy as my loss function. I have approx. 147,000 images in my data set, and my goal is to correctly classify 150 tags, (although I have access to over 500). my classes are highly imbalanced, however I have been applying weights (I’ve been using the class_weight parameter to administer my weights) and my model looks like this : 

model = Sequential([ Input(shape=(None, None,3)), experimental.preprocessing.RandomRotation(0.2), Conv2D(4,(7,7),activation='relu'), MaxPooling2D(pool_size=(2,2)), Conv2D(4,(7,7),activation='relu'), Conv2D(4,(5,5),activation='relu'), Conv2D(4,(5,5),activation='relu'), Conv2D(8,(5,5),activation='relu'), Conv2D(16,(5,5),activation='relu'), Conv2D(32,(3,3),activation='relu'), Conv2D(64,(3,3),activation='relu'), Conv2D(128,(3,3),activation='relu'), Conv2D(256,(3,3),activation='relu'), Conv2D(256,(3,3),activation='relu'), GlobalMaxPooling2D(), Flatten(), Dropout(0.4), Dense(256,activation='relu'), Dense(256,activation='relu'), Dropout(0.2), Dense(256,activation='relu'), Dense(len(classes), activation='sigmoid') ])

I have tried alternate last layer activation functions, to no avail. I have also decreased the number of convolutional layers, decreased the number of dense layers, increased the number of dense layers, increased learning rate, decreased learning rate, I even played around with different weight values. Just writing this has given me insight into the workings of my network, and I may have an idea as to what the issue is, however I would like to hear any untainted suggestions, and recommendations. Any tips for general performance enhancements and the like would also be greatly appreciated.

Edit 1 : I’ve attempted a custom weighted binary crossentropy loss function that has worked for other models in the past, however, it is now throwing an error. here is the loss function 

def get_weighted_loss(weights): def weighted_loss(y_true, y_pred): return K.mean((weights[:,0]**(1-y_true))*(weights[:,1]**(y_true))*K.binary_crossentropy((y_true), y_pred), axis=-1) return weighted_loss

and the error is this 

Traceback (most recent call last): File "C:Userscws72tensorflowProjectsMulti-Label-Training-V5.py", line 163, in <module> history = model.fit(train_data.padded_batch(BATCH_SIZE).prefetch(tf.data.AUTOTUNE).repeat(), File "C:Userscws72anaconda3envsTensorflow-GPU-WorkDirlibsite-packageskerasenginetraining.py", line 1158, in fit tmp_logs = self.train_function(iterator) File "C:Userscws72anaconda3envsTensorflow-GPU-WorkDirlibsite-packagestensorflowpythoneagerdef_function.py", line 889, in __call__ result = self._call(*args, **kwds) File "C:Userscws72anaconda3envsTensorflow-GPU-WorkDirlibsite-packagestensorflowpythoneagerdef_function.py", line 933, in _call self._initialize(args, kwds, add_initializers_to=initializers) File "C:Userscws72anaconda3envsTensorflow-GPU-WorkDirlibsite-packagestensorflowpythoneagerdef_function.py", line 763, in _initialize self._stateful_fn._get_concrete_function_internal_garbage_collected( # pylint: disable=protected-access File "C:Userscws72anaconda3envsTensorflow-GPU-WorkDirlibsite-packagestensorflowpythoneagerfunction.py", line 3050, in _get_concrete_function_internal_garbage_collected graph_function, _ = self._maybe_define_function(args, kwargs) File "C:Userscws72anaconda3envsTensorflow-GPU-WorkDirlibsite-packagestensorflowpythoneagerfunction.py", line 3444, in _maybe_define_function graph_function = self._create_graph_function(args, kwargs) File "C:Userscws72anaconda3envsTensorflow-GPU-WorkDirlibsite-packagestensorflowpythoneagerfunction.py", line 3279, in _create_graph_function func_graph_module.func_graph_from_py_func( File "C:Userscws72anaconda3envsTensorflow-GPU-WorkDirlibsite-packagestensorflowpythonframeworkfunc_graph.py", line 999, in func_graph_from_py_func func_outputs = python_func(*func_args, **func_kwargs) File "C:Userscws72anaconda3envsTensorflow-GPU-WorkDirlibsite-packagestensorflowpythoneagerdef_function.py", line 672, in wrapped_fn out = weak_wrapped_fn().__wrapped__(*args, **kwds) File "C:Userscws72anaconda3envsTensorflow-GPU-WorkDirlibsite-packagestensorflowpythonframeworkfunc_graph.py", line 986, in wrapper raise e.ag_error_metadata.to_exception(e) StagingError: in user code: C:Userscws72anaconda3envsTensorflow-GPU-WorkDirlibsite-packageskerasenginetraining.py:830 train_function * return step_function(self, iterator) C:Userscws72anaconda3envsTensorflow-GPU-WorkDirlibsite-packageskerasenginetraining.py:813 run_step * outputs = model.train_step(data) C:Userscws72anaconda3envsTensorflow-GPU-WorkDirlibsite-packageskerasenginetraining.py:771 train_step * loss = self.compiled_loss( C:Userscws72anaconda3envsTensorflow-GPU-WorkDirlibsite-packageskerasenginecompile_utils.py:201 __call__ * loss_value = loss_obj(y_t, y_p, sample_weight=sw) C:Userscws72anaconda3envsTensorflow-GPU-WorkDirlibsite-packageskeraslosses.py:142 __call__ * losses = call_fn(y_true, y_pred) C:Userscws72anaconda3envsTensorflow-GPU-WorkDirlibsite-packageskeraslosses.py:246 call * return ag_fn(y_true, y_pred, **self._fn_kwargs) C:Userscws72tensorflowProjectsMulti-Label-Training-V5.py:24 weighted_loss * return K.mean((weights[:,0]**(1-y_true))*(weights[:,1]**(y_true))*K.binary_crossentropy((y_true), y_pred), axis=-1) IndexError: too many indices for array: array is 1-dimensional, but 2 were indexed

​

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Misc

On-Demand Session: Deploying Edge AI in Manufacturing

At GTC ’21, Data Monsters, who builds AI solutions for production and packaging, discussed the growth of AI in manufacturing and how AI is being used to optimize every part of the supply chain, from forecasting and production planning to quality control.

When it comes to production, companies spend endless cycles improving their processes to drive the most revenue. Manufacturing lines are rigorously tested, and any changes require downtime that can eat up a company’s profits. That’s where AI comes in.

Manufacturing as an industry is ripe to experience the benefits of AI because it performs highly repeatable tasks that can each be tuned and optimized for overall performance. AI takes readily-available historical data from sensors, cameras, and even outcomes and processes it faster than any human could, without getting tired. Once the data is fed into the AI, the AI makes sense of it, then it has to make a prediction based on past data, it makes a choice based on the best option available, and finally it takes action.

At GTC ’21, Data Monsters, who builds AI solutions for production and packaging, discussed the growth of AI in manufacturing and how AI is being used to optimize every part of the supply chain, from forecasting and production planning to quality control. The session “Getting Started with AI in Manufacturing” shared how AI could be used to improve the Overall Equipment Effectiveness (OEE) of any organization using data that is already available today. 

OEE consists of three factors: availability, performance, and quality. Each of these factors can be optimized to improve the effectiveness and therefore profits of manufacturers. Let’s take a look at the various AI techniques that can be used for each.

Figure 1. Overall Equipment Effectiveness KPIs for manufacturing

Availability is measured by the amount of uptime compared to downtime. As downtime at any part of the system can result in dramatic productivity loss, predictive maintenance is something many manufacturers are looking to in order to improve the uptime of machinery. Predictive maintenance models learn from the system and identify indicators that predict a failure. This model can alert the team prior to a failure and make recommendations about what needs to be fixed, both of which can reduce downtime. 

Performance looks at how fast products are being produced compared to how fast they could be produced. With highly repetitive tasks in the manufacturing space, AI can be used to help identify the most efficient schedule based on objective function parameters, and make suggestions on where bottlenecks can be removed. Depending on the parameters, process optimization can determine the most efficient outcome based on technology variables and historical outcomes, thus maximizing throughput, minimizing cost, and reducing leftover stock.

Quality of production means looking at what proportion of products are being produced without defects. Here, computer vision provides a lot of data for analysis. Manufacturers can improve the overall quality by identifying where in the process the defects are happening so they can be prevented in the future. Reducing defects and improving the overall quality of products can have a dramatic impact on not only productivity, but also revenue. 

Figure 2. Data Monsters trained AI that identifies visual anomalies on the product and alerts the packaging line operator in real-time.

AI becomes a huge differentiator in the manufacturing space, as it reduces manual operation, and improves efficiency and the competitive position in the market with optimized costs and scheduling. 

Due to the intense calculations of AI required to perform these tasks, manufacturers are bringing the compute close to sensors generating the data. Moving compute to the edge has the benefit of lowering latency and bandwidth requirements to run AI applications, ensuring the fastest and most accurate responses. With numerous compute systems on production lines, AI models are downloaded from the cloud, data is collected and processed locally. Models are fine-tuned and uploaded back to the cloud for further distribution between several edge systems.

To learn more about implementing inspections, diagnostics, and predictive maintenance in the manufacturing pipeline, check out the Data Monster’s session “Getting Started with AI in Manufacturing“.