Getting Started with MobileNetV2 for Image Classification

Apr 28, 2023 | Educational

In this article, we will explore how to use the MobileNetV2 image classification model, which has been fine-tuned using the renowned ImageNet-1k dataset. This model is pivotal in the realm of deep learning, especially for tasks related to image recognition owing to its efficiency and performance.

Understanding the Model

The MobileNetV2 model is based on a feature backbone that utilizes a few key components:

  • RandAugment RA Recipe: An advanced data augmentation technique that improves the model’s robustness.
  • RMSProp Optimizer: An adaptive learning rate optimizer that enhances the training process.
  • Step Learning Rate Schedule: A method that adjusts the learning rate during training for better convergence.

With approximately 3.5 million parameters and an efficient structure, this model can perform image classification efficiently with a minimal computational budget.

How to Use MobileNetV2 for Image Classification

Let’s dive into practical usage! The code below illustrates how to classify an image using MobileNetV2:

from urllib.request import urlopen
from PIL import Image
import timm

# Load image from URL
img = Image.open(urlopen('https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/beignets-task-guide.png'))

# Create and evaluate the model
model = timm.create_model('mobilenetv2_100.ra_in1k', pretrained=True)
model = model.eval()

# Data configuration and transformation
data_config = timm.data.resolve_model_data_config(model)
transforms = timm.data.create_transform(**data_config, is_training=False)

# Classify the image
output = model(transforms(img).unsqueeze(0))  # unsqueeze single image into batch of 1
top5_probabilities, top5_class_indices = torch.topk(output.softmax(dim=1) * 100, k=5)

Explaining the Code Using an Analogy

Think of the MobileNetV2 classification process as a chef preparing a gourmet dish. Here’s how the code functions:

  • **Gathering Ingredients:** The image is sourced from a URL, just like a chef gathers fresh ingredients.
  • **Prepping the Kitchen:** The model is created (like setting up the kitchen), and it prepares to receive the image.
  • **Cooking Process:** The data transformations normalize and resize the image, akin to prepping the ingredients before cooking.
  • **Serving the Dish:** The model produces the final probabilities of various classes, just like a chef serving a beautifully plated meal, showcasing the best options to the diner.

Feature Map Extraction

If you need to extract feature maps instead of just classifying an image, you can modify the code slightly:

model = timm.create_model('mobilenetv2_100.ra_in1k', pretrained=True, features_only=True)
model = model.eval()

# Classify and get feature maps
output = model(transforms(img).unsqueeze(0))

# Print shapes of feature maps
for o in output:
    print(o.shape)

Image Embeddings

If you want to obtain embeddings from the model, here’s how you can do it:

model = timm.create_model('mobilenetv2_100.ra_in1k', pretrained=True, num_classes=0)  
model = model.eval()

# Get the embeddings
output = model(transforms(img).unsqueeze(0))

Troubleshooting Tips

If you encounter issues while using this model, consider the following:

  • Ensure the image URL is correct and the image is accessible.
  • Check your Python environment has all required libraries installed (like torch and PIL).
  • If the model doesn’t seem to perform well, experiment with different transformations or fine-tuning the parameters.

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

Conclusion

In today’s AI landscape, MobileNetV2 emerges as a robust tool for efficient image classification. With its elegant architecture and powerful features, it serves to achieve remarkable results with limited resources.

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.

Stay Informed with the Newest F(x) Insights and Blogs

Tech News and Blog Highlights, Straight to Your Inbox