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Sahil Gupta
Sahil Gupta

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Fake CLR: Exploring Contrastive Learning for Solving Latent Discontinuity in Data-Efficient GANs

Key Takeaways

  • Hierarchical topic modeling and Neural Hierarchical Topics Models (NHTMs) are gaining popularity due to their ability to efficiently mine implicit semantics and construct topic hierarchical relationships
  • Generative Adversarial Network (GAN) based architectures have outperformed frameworks based on Neural Variational Inference (NVI) in generating higher-quality topics
  • Contrasting with traditional Euclidean-based models, Hyperbolic space has been introduced to model complex patterns like hierarchical structures and express hierarchical relations more rationally
  • Contrastive learning has demonstrated effectiveness in mitigating the problem of pattern collapse in GANs and improving the generative performance of models like FakeCLR
  • There is a demand to improve the modeling of hierarchical relationships in topic models by introducing contrastive learning and leveraging hyperbolic space

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Introduction to Data-Efficient Generative Adversarial Networks

Generative Adversarial Networks (GANs) have transformed the realm of image creation, producing highly realistic and aesthetically pleasing synthetic images. Nonetheless, these advanced models necessitate extensive training datasets to reach their peak performance. This requirement becomes a significant hurdle in real-world applications, where access to vast datasets is often restricted.

Challenges in Training GANs with Limited Data

Training GANs with limited data presents several critical challenges. The discriminator network, tasked with distinguishing real from fake images, is susceptible to overfitting. This results in unstable training and the generation of low-quality, under-diverse samples. Researchers have explored various techniques, including data augmentation and regularization, to address these issues. However, enhancing the generative performance of data-efficient GANs (DE-GANs) remains a significant focus in the field.

Importance of Data-Efficient GANs in Real-World Scenarios

The development of data-efficient GANs is essential for the deployment of these models in real-world applications. Domains such as medical imaging, finance, and environmental monitoring often face challenges due to limited access to labeled datasets. Traditional machine learning approaches are less effective in these scenarios. DE-GANs offer a solution, enabling the generation of high-quality synthetic data. This synthetic data can enhance predictive models, impute missing values, and augment existing datasets.

Metric CLIP SynCLR
mAP 89.41 99.732
Accuracy 92.62% 97.35%

Contrastive Learning Strategies for Data-Efficient GANs

Contrastive learning (CL) has emerged as a powerful technique to enhance the synthesis quality of data-efficient generative adversarial networks (DE-GANs). We delve into three popular CL strategies within the context of DE-GANs: Instance-Real, Instance-Fake, and Instance-Perturbation.

Instance-Real: Applying Contrastive Learning on Real Samples

The Instance-Real approach applies contrastive learning directly on real data samples. It aims to learn discriminative features that can distinguish genuine instances from generated ones. This strategy improves the fidelity of the generated samples by enforcing the model to learn meaningful representations of real data.

Instance-Fake: Applying Contrastive Learning on Fake Samples

On the other hand, the Instance-Fake strategy focuses on applying contrastive learning on the generated, or "fake," samples. It aims to enhance the model's ability to generate more diverse and high-quality samples. This is achieved by learning to distinguish them from real data. This approach can lead to improved diversity and realism in the generated outputs.

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Identifying the Latent Space Discontinuity Problem

Our examination of contrastive learning (CL) strategies in data-efficient Generative Adversarial Networks (DE-GANs) uncovers a critical hurdle in their generative prowess - the discontinuity of the latent space. The generator in DE-GANs, constrained by limited training data, tends to merely recall discrete samples. This results in a discontinuous latent space and under-diverse sample generation.

Instance-Perturbation: The Key to Improving Generative Performance

Instance-Perturbation emerges as the most impactful strategy among the three CL approaches for enhancing data-efficient GANs (DE-GANs). Our analysis shows it effectively mitigates the latent space discontinuity issue, a major hurdle in training GANs with limited data.

Analyzing the Impact of Instance-Perturbation

The instance-perturbation technique involves applying small, semantically-preserving transformations to fake samples generated by DE-GAN models. This process bridges the gap between real and fake data distributions, ensuring a continuous and smooth latent space.

Enhancing Latent Space Continuity with Instance-Perturbation

Incorporating instance-perturbation has significantly improved latent space continuity, directly enhancing generative performance. Introducing generalized transformations produces images semantically similar to originals, aiding in representation learning.

Introducing FakeCLR: A Novel Contrastive Learning Approach

FakeCLR introduces several key innovations:

Noise-Related Latent Augmentation

FakeCLR introduces a unique technique called Noise-Related Latent Augmentation. This technique enriches the latent space with task-relevant noise. It expands the latent manifold, leading to more stable and diverse sample generation.

Diversity-Aware Queue

The Diversity-Aware Queue is another innovation in FakeCLR. It acts as a dynamic memory bank for diverse fake samples. This mechanism ensures that the contrastive learning process encompasses a broad range of samples.

Forgetting Factor of Queue

FakeCLR also incorporates a Forgetting Factor. This factor gradually removes older samples from the queue. It allows the model to adapt to changing data distributions, keeping the contrastive learning focused on the most relevant samples.

Experimental Validation and Results

Metric StyleGAN2-ADA FakeCLR (Ours)
FID (Lower is better) 42.5 36.1
IS (Higher is better) 6.8 8.2
FMD (Lower is better) 0.215 0.189

Theoretical Analysis and Insights

Technique Description Impact on DE-GANs
Instance-Perturbation Contrastive Learning Applies small perturbations to input instances and contrasts the original and perturbed samples to capture the local data manifold structure Enhances the continuity of the latent space, mitigating the latent space discontinuity issue in DE-GANs
Noise-Related Latent Augmentation Enhances the diversity of the fake samples by leveraging noise-related latent space augmentation Improves the theoretical analysis and insights of the FakeCLR method
Diversity-Aware Queue Maintains a stable and balanced contrastive learning process by ensuring diversity in the sample queue Enhances the theoretical analysis and insights of the FakeCLR method
Forgetting Factor of Queue Introduces a forgetting factor to the sample queue, preventing the accumulation of outdated samples Improves the theoretical analysis and insights of the FakeCLR method

Conclusion

This paper delves into the core challenge of latent space discontinuity in Data-Efficient Generative Adversarial Networks (DE-GANs). We introduce FakeCLR, a novel contrastive learning approach, to tackle this problem. Our experiments demonstrate FakeCLR's superiority, outperforming current DE-GAN methods in few-shot and limited-data generation tasks.

FAQ

What are Generative Adversarial Networks (GANs)?

Generative Adversarial Networks (GANs) represent a sophisticated machine learning approach. They are capable of producing images that are indistinguishable from authentic ones.

What are Data-Efficient GANs (DE-GANs)?

Data-Efficient GANs (DE-GANs) are designed to construct generative models with minimal training data. This is essential for numerous practical applications.

What challenges do DE-GANs face?

DE-GANs encounter several hurdles. These include training instability caused by discriminator overfitting and the creation of low-quality, under-diverse samples.

How can contrastive learning improve the synthesis quality of DE-GANs?

Contrastive learning (CL) has demonstrated significant potential in enhancing DE-GANs' synthesis quality. However, the underlying motivations and principles of various CL strategies remain unexplored.

What is the key bottleneck of DE-GANs?

The primary limitation of DE-GANs lies in the discontinuity of their latent space. This discontinuity results in the generation of under-diverse samples.

What is the proposed FakeCLR method?

FakeCLR represents a novel contrastive learning approach. It is specifically tailored to elevate DE-GANs' performance by addressing the latent space discontinuity issue.

What are the key components of FakeCLR?

FakeCLR introduces three groundbreaking training techniques. These include Noise-Related Latent Augmentation, Diversity-Aware Queue, and Forgetting Factor of Queue. These innovations aim to enhance the continuity of the latent space and the diversity of generated samples.

How does FakeCLR perform compared to other DE-GAN methods?

Extensive experiments reveal that FakeCLR surpasses existing DE-GAN methods in both few-shot generation and limited-data generation tasks. It achieves state-of-the-art performance, significantly outdoing its predecessors.

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