A couple of questions about an UNET CNN implementation in Tensorflow

So I am a beginner in this field, for a summer project, I took datasets of chest CT scans and lesions and aimed to segment them, and to diagnose specific ILDs(interstitial lung diseases) based on them. My chest segmentation model runs very well(acc>98%), but its the lesion segmentation part(which I hope will diagnose specific diseases) which is giving me problems. So my model is a multi-class model, with 17 classes(same as labels and features too right?) such as ground_glass, fibrosis, bronchial_wall_thickening and so on,and the way it works is that if the input has a specific set of these features, a specific disease can be diagnosed. 17 classes seem too much for my system(32 gb DDR4, RTX 2060 mobile), and the code crashes during the train-test split part. The code runs well if I do not read the full dataset(which contains 1724 train and 431 test images, all 512x512x1), but then I get confused which classes are being processed, and how significant are the parameter values. How should I proceed to run my model without my IDE crashing due to RAM overload, and will Colab pro do the trick? Also what can I optimize in my code, will resizing the images to 128x128x1 help? And if yes how do I proceed with that?

P.S: Here my code(the dataset is not uploaded haha but my thought process would be better understood there)

P.Sx2: Also posted this on the DeepLearning sub, my apologies if you had to read this twice.

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Upcoming Event: How to Build an Edge Solution

​Join us on June 16 to take a deep dive into AI at the edge and learn how you can build an edge computing solution that delivers real-time results.


What is Extended Reality?

Advances in extended reality have already changed the way we work, live and play, and it’s just getting started. Extended reality, or XR, is an umbrella category that covers a spectrum of newer, immersive technologies, including virtual reality, augmented reality and mixed reality. From gaming to virtual production to product design, XR has enabled people Read article >

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Best Practices: Explainable AI Powered by Synthetic Data

Learn how financial institutions are using high-quality synthetic data to validate explainable AI models and comply with data privacy regulations.

Data sits at the heart of model explainability. Explainable AI (XAI) is a rapidly advancing field looking to provide insights into the complex decision-making processes of AI algorithms.

Where AI has a significant impact on individuals’ lives, like credit risk scoring, managers and consumers alike rightfully demand insight into these decisions. leading financial institutions are already leveraging XAI for validating their models. Similarly, regulators are also demanding insight into financial institutions’ algorithmic environment. But how is it possible to do that in practice?

Pandora’s closed box

The more advanced AI gets, the more important data becomes for explainability.

Modern day ML algorithms have ensemble methods and deep learning that result in thousands, if not millions of model parameters. They are impossible to grasp without seeing them in action when applied to actual data.

The need for broad access to data is apparent even and especially in cases where the training data is sensitive. Financial and healthcare data used for credit scoring and insurance pricing are some of the most frequently used, but also some of the most sensitive data types in AI.

It’s a conundrum of opposing needs: You want your data protected and you want a transparent decision.

Explainable AI needs data

So, how can these algorithms be made transparent? How can you judge model decisions made by machines? Given their complexity, disclosing the mathematical model, implementation, or the full training data won’t serve the purpose.

Instead, you have to explore a system’s behavior by observing its decisions across a variety of actual cases and probe its sensitivity with respect to modifications. These sample-based, what-if explorations help our understanding of what drives the decision of a model.

This simple yet powerful concept of systematically exploring changes in model output given variations of input data is also referred to as local interpretability and can be performed domain– and model-agnostic at scale. Thus, the same principle can be applied to help interpret credit-scoring systems, sales demand forecasts, fraud detection systems, text classifiers, recommendation systems, and more.

However, local interpretability methods like SHAP require access not only to the model but also to a large number of representative and relevant data samples.

Figure 1 shows a basic demonstration, performed on a model, predicting customer response to marketing activity within the finance industry. Looking at the corresponding Python calls reveals the need for the trained model, as well as a representative dataset for performing these types of analyses. However, what if that data is actually sensitive and can’t be accessed by AI model validators?

Driver analysis and dependency plots based on real-world data are built using SHAP, a local interpretability method.
Figure 1. Example of model explainability through SHAP using actual data

Synthetic data for scaling XAI across teams

In the early days of AI adoption, it was typically the same group of engineers who developed models and validated them. In both cases, they used real-world production data.

Given the real-world impact of algorithms on individuals, it is now increasingly understood that independent groups should inspect and assess models and their implications. These people would ideally bring diverse perspectives to the table from engineering and non-engineering backgrounds.

External auditors and certification bodies are being contracted to establish additional confidence that the algorithms are fair, unbiased, and nondiscriminative. However, privacy concerns and modern-day data protection regulations, like GDPR, limit access to representative validation data. This severely hampers model validation being broadly conducted.

Fortunately, model validation can be performed using high-quality AI-generated synthetic data that serves as a highly accurate, anonymized, drop-in replacement for sensitive data. For example, MOSTLY AI’s synthetic data platform enables organizations to generate synthetic datasets in a fully self-service, automated manner.

Figure 2 shows the XAI analysis being performed for the model with synthetic data. There are barely any discernible differences in results when comparing Figure 1 and Figure 2. The same insights and inspections are possible by leveraging MOSTLY AI’s privacy-safe synthetic data, which finally enables true collaboration to perform XAI at scale and on a continuous basis.

Driver analysis and dependency plots based on synthetic data are built using SHAP, a local interpretability method.
Figure 2. Example of model explainability through SHAP using synthetic data

Figure 3 shows the process of scaling model validation across teams. An organization runs a state-of-the-art synthetic data solution within their controlled compute environment. It continuously generates synthetic replicas of their data assets, which can be shared with a diverse team of internal and external AI validators.

Flow diagram depicting financial institutions using real-world data to generate synthetic data for external AI auditing and validation.
Figure 3. Process flow for model validation through synthetic data

Scaling to real-world data volumes with GPUs

GPU-accelerated libraries, like RAPIDS and Plotly, enable model validation at the scale required for real-world use cases encountered in practice. The same applies to generating synthetic data, where AI-powered synthetization solutions such as MOSTLY AI can benefit significantly from running on top of a full-stack accelerated computing platform. For more information, see Accelerating Trustworthy AI for Credit Risk Management.

To demonstrate, we turned to the mortgage loan dataset published by Fannie Mae (FNMA) for the purpose of validating an ML model for loan delinquencies. We started by generating a statistical representative synthetic replica of the training data, consisting of tens of millions of synthetic loans, composed of dozens of synthetic attributes (Figure 4).

All data is being artificially created and no single record can be linked back to any actual record from the original dataset. However, the structure, patterns, and correlations of the data are faithfully retained in the synthetic dataset.

This ability to capture the diversity and richness of data is critical for model validation. The process seeks to validate model behavior not only on the dominant majority classes but also on under-represented and most vulnerable minority segments within a population.

Comparison of real and synthetic Fannie Mae mortgage loan datasets used to validate machine learning models for loan delinquencies.
Figure 4. A snapshot of real and synthetic data samples

Given the generated synthetic data, you can then use GPU-accelerated XAI libraries to compute statistics of interest to assess model behavior.

Figure 5, for example, displays a side-by-side comparison of SHAP values: the loan delinquency model being explained on the real data and after being explained on the synthetic data. The same conclusions regarding the model can be reliably derived by using high-quality synthetic data as a drop-in alternative to the sensitive original data.

Side-by-side comparison of SHAP values for loan delinquency models explained by real-world and synthetic data shows similar conclusions.
Figure 5. SHAP values of the ML model for loan delinquencies

Figure 5 shows that synthetic data serves as a safe drop-in replacement for the actual data for explaining model behavior.

Further, the ability of synthetic data generators to yield an arbitrary amount of new data enables you to improve the model validation significantly for smaller groups.

Figure 6 shows a side-by-side comparison of SHAP values for a specific ZIP code found within the dataset. While the original data had less than 100 loans for a given geography, we leverage 10x the data volume to inspect the model behavior in that area, enabling more detail and richer insights.

Side-by-side comparison of SHAP values for a specific ZIP code found within the mortgage loan delinquency dataset using synthetic data oversampling for richer insights.
Figure 6. Richer insights by performing model validation with synthetic oversampling

Individual-level inspection with synthetic samples

While summary statistics and visualizations are key to analyzing the general model behavior, our understanding of models further benefits from inspecting individual samples on a case-by-case basis.

XAI tooling reveals the impact of multiple signals on the final model decision. These cases need not necessarily be actual cases, as long as synthetic data is realistic and representative.

Figure 7 displays four randomly generated synthetic cases with their final model predictions and corresponding decomposition for each of the input variables. This enables you to gain insights on what factor contributed to what extent and what direction to the model decision for unlimited potential cases without exposing the privacy of any individual.

Four randomly generated synthetic datasets with final model predictions and corresponding decomposition for each of the input variables.
Figure 7. Inspecting model predictions of four randomly sampled synthetic records

Effective AI governance with synthetic data

AI-powered services are becoming more present across private and public sectors, playing an ever bigger role in our daily lives. Yet, we are only at the dawn of AI governance.

While regulations, like Europe’s proposed AI Act, will take time to manifest, developers and decision-makers must act responsibly today and adopt XAI best practices. Synthetic data enables a collaborative, broad setting, without putting the privacy of customers at risk. It’s a powerful, novel tool to support the development and governance of fair and robust AI.

For more information about AI explainability in banking, see the following resources:


From Cloud to Car: How NIO Develops Intelligent Vehicles on NVIDIA HGX

Building next-generation intelligent vehicles requires an AI infrastructure that pushes the cutting edge. Electric vehicle maker NIO is using NVIDIA HGX to build a comprehensive data center infrastructure for developing AI-powered, software-defined vehicles. With high-performance compute, the automaker can continuously iterate on sophisticated deep learning models, creating robust autonomous driving algorithms in a closed-loop environment. Read article >

The post From Cloud to Car: How NIO Develops Intelligent Vehicles on NVIDIA HGX appeared first on NVIDIA Blog.


Issue with Val accuracy never changing

I’m building a model that categorizes 1/2s of data at a 256 sample rate, the input has a shape of (128, 4) and is flattened. The output has 9 different classes. I can’t seem to correctly tune the hidden layers. As soon as I start training. Training accuracy jumps to 95is percent with a very low loss, but my Val accuracy is 0.1111, which is what I expect from guessing a random class, and my Val loss is always much much higher than training loss.

Should I use a different optimizer? Different activations? What are your Guy’s recommendations?

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Loss is decreasing and accuracy is increasing but wrong predictions

I am trying to perform an image segmentation task on 3d images. As preprocessing I slice the images into 2d images.

The images do contain multiple labels. As a loss function I use the tf.keras.losses.SparseCategoricalCrossentropy and as metric I do use tf.keras.metrics.SparseCategoricalAccuracy.

When I train the model on 2 2d slices the accuracy becomes 0.99 and the loss is very low, however when I save the model and predict on the same 2 images, the prediction are completely wrong.

Has anybody an idea what I could be missing?

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VGG16 on cifar10 training time

How long should it take to train VGG16 on cifar10? I tried using Apple M1 with Tensorflow-Metal plugging, but it crashes. Then tried in google colab, but it also crashes with error “Your session crashed after using all available RAM.”. Is this normal?? I’ve heard this was supposed to take minutes to train

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NVIDIA Stockholder Meeting Set for June 2; Individuals Can Participate Online

SANTA CLARA, Calif., May 19, 2022 — NVIDIA today announced it will hold its 2022 Annual Meeting of Stockholders online on Thursday, June 2, at 11 a.m. PT. The meeting will take place virtually…


NVIDIA Announces Upcoming Event for Financial Community

SANTA CLARA, Calif., May 19, 2022 — NVIDIA will present at the following event for the financial community:

BofA 2022 Securities Global Technology Conference
Tuesday, June 7, at 8 a.m. Pacific…