Micro Organism Classification

This project focuses on classifying microorganisms using deep learning techniques. It involves two parts: training custom CNN models from scratch and fine-tuning a pre-trained ResNet-18 network. The dataset consists of images of different microorganisms, divided into various classes.

Part-1: Training Custom CNN Models

In this part, custom CNN models are built and trained from scratch without using pre-trained weights. The models are designed to learn features specific to the Micro_Organism dataset. The steps involved are as follows:

1. Dataset Preparation:

   • The dataset is organized into folders, with each folder representing a specific microorganism class.
   • Images are resized, converted to tensors, and normalized.
   • The dataset is split into train, validation, and test sets.

2. Model Architecture:

   • Two models are defined: ModelWithoutResidual and ModelWithResidual.
   • ModelWithoutResidual uses standard convolutional layers, max pooling, and fully connected layers.
   • ModelWithResidual incorporates residual blocks in addition to the standard layers.

3. Training and Evaluation:

   • Models are trained using the training set and evaluated on the validation set.
   • Hyperparameters such as learning rate and batch size are varied to find the best model.
   • Loss and accuracy curves are plotted to visualize the training progress.
   • The model with the highest validation accuracy is selected and evaluated on the test set.

Part-2: Fine-tuning a Pre-trained ResNet-18 Network

In this part, a pre-trained ResNet-18 network is used and fine-tuned to classify the microorganism images. The steps involved are as follows:

1. Pre-trained Model:

   • The ResNet-18 network, pre-trained on the ImageNet dataset, is loaded.
   • All layers except the fully connected layer are frozen.

2. Model Modification:

   • The last fully connected layer is modified to match the number of classes in the Micro_Organism dataset.
   • The weights of the last layer are randomly initialized.

3. Training and Evaluation:

   • Two cases are explored: training only the fully connected layer and freezing the rest, and training the last two convolutional layers and the fully connected layer while freezing the rest.
   • Models are trained using the training set and evaluated on the validation and test sets.
   • Accuracy on the validation and test sets is recorded for comparison.

Results and Analysis:

1. Part-1 vs. Part-2:

   • Fine-tuning the pre-trained network outperformed training from scratch in terms of accuracy and training efficiency.
   • Fine-tuning utilized the learned features of the pre-trained network, leading to improved generalization and faster convergence.

2. Conclusion:

   • Fine-tuning a pre-trained network is a powerful technique, especially when working with limited training data or when a pre-trained model is available on a related task.
   • The best model achieved higher accuracy on the validation and test sets compared to the models trained from scratch.

Dependencies:

• Python (>=3.6)
• PyTorch (>=1.7.0)
• Torchvision (>=0.8.0)
• Matplotlib (>=3.3.0)