How to Implement ResNet18 for Image Classification Using Axon

Mar 26, 2022 | Educational

If you’re venturing into the world of image classification, utilizing the ResNet18 model can be a powerhouse in your machine learning arsenal. The ResNet architecture revolutionizes how we train deeper neural networks, making it possible to achieve higher accuracy without compromising performance. This guide will walk you through implementing ResNet18 translated from ONNX into Axon. Let’s dive in!

What is ResNet18?

ResNet, or Residual Network, was designed to overcome the challenges associated with training deeper networks. Traditional deep networks struggled with achieving optimal performance as the number of layers increased due to vanishing gradients. ResNet employs a unique approach: it learns residual functions with reference to the layer inputs. This allows for enhanced optimization and better accuracy, enabling ResNet to use networks with depths of up to 152 layers.

Use Cases of ResNet

  • Image Classification: Categorizes images into pre-defined classes.
  • Transfer Learning: Serves as a base to refine models in different domains by leveraging learned features.
  • High Accuracy Applications: The low model sizes and high accuracies make it ideal for many machine learning tasks.

Getting Started with ResNet18 in Axon

To effectively implement ResNet18, you’ll need the following:

Code Implementation

Here’s a simplified analogy to understand the structure of our code:

Imagine you are building a multi-level parking garage. Each level represents a layer of the network, where cars (features) are introduced on every floor. However, as you go higher (deeper), it’s easy for these cars to get lost. The idea of “residual” learning is like putting elevators (residual connections) between floors that allow cars to get back down to previously visited levels, ensuring they don’t just get stacked up without purpose.

Here’s how you would typically perform the steps:


# Load the model
model = Axon.from_pretrained('resnet18')

# Preprocess the input images
preprocessed_images = preprocess_images(raw_images)

# Run inference
output_scores = model(preprocessed_images)

# Post-process the output
probabilities = softmax(output_scores)

Preprocessing Images

Before feeding images to the model, ensure they are normalized. Resize your images to at least 224×224 pixels and normalize them to a scale of [0, 1]. The transformations you need are:

  • Mean: [0.485, 0.456, 0.406]
  • Std: [0.229, 0.224, 0.225]

This step is crucial for accurate predictions.

Post-Processing Results

After getting the output scores from the model, the post-processing involves calculating the softmax probability scores for each class. You can sort them to report the most likely classifications. Reference the imagenet_postprocess.py for a complete code.

Troubleshooting

If you encounter issues when running the model or preprocessing images, consider the following:

  • Ensure the images are of the correct size and type (JPEG).
  • Check that the normalization parameters are correctly applied.
  • Verify that your model is loaded correctly from the correct source.

For more insights, updates, or to collaborate on AI development projects, stay connected with fxis.ai.

Final Thoughts

Implementing ResNet18 in Axon can be a game-changer for your image classification tasks. The benefits of residual learning and transfer learning can vastly reduce the time and computational resources required to train an accurate model.

At fxis.ai, we believe that such advancements are crucial for the future of AI, as they enable more comprehensive and effective solutions. Our team is continually exploring new methodologies to push the envelope in artificial intelligence, ensuring that our clients benefit from the latest technological innovations.

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