torinriley/SSL-ImgClassification

Self-Supervised Learning Framework

This project implements a Self-Supervised Learning (SSL) framework using the CIFAR-10 dataset and a ResNet-18 backbone. The goal of the project is to train a model to learn robust image representations without relying on labeled data. This framework utilizes contrastive learning with data augmentations and a custom contrastive loss function.

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Features

Data Augmentation:

• Random cropping, flipping, color jitter, grayscale conversion, Gaussian blur, and normalization.

Backbone Architecture:

• ResNet-18 with a custom projection head.

Contrastive Learning:

• Contrastive loss function with positive and negative pair sampling.

Optimization:

• Gradient clipping and weight decay for numerical stability.

Model Checkpointing:

• Save model weights at the end of each epoch.

How It Works

1. Data Augmentation:

   • Two augmented views of each image are created for contrastive learning.

2. Contrastive Loss:

   • Positive pairs: Augmented views of the same image.
   • Negative pairs: Augmented views of different images.
   • Loss is computed using the similarity of positive pairs while minimizing similarity with negative pairs.

3. Optimization:

   • The model uses the Adam optimizer with a learning rate of 3e-4 and weight decay of 1e-4.
   • Gradient clipping ensures numerical stability.

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Results and Evaluation

• Training Loss:
  • Observe the training loss decreasing across epochs, indicating successful representation learning.
• Downstream Tasks:
  • Evaluate the learned embeddings on classification or clustering tasks.

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Acknowledgments

• CIFAR-10 dataset: https://www.cs.toronto.edu/~kriz/cifar.html
• PyTorch: https://pytorch.org/
• ResNet-18 architecture.

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