Clarification on Self-Attention vs. Spatial and Channel Attention, and Their Implementations in MATLAB

I’m researching attention mechanisms in deep learning, and I have a couple of questions regarding their functionalities and implementations:

1. Functional Differences: Does self-attention fulfill the same role as spatial attention and channel attention, or do they address different aspects of feature importance? How do they compare in terms of what they aim to achieve?
2. Implementations in MATLAB: I know that self-attention layers have been implemented in MATLAB since R2023a (selfAttentionLayer). Are there built-in functions for implementing spatial attention and channel attention layers in MATLAB as well? If not, could you suggest ways to implement them?

I appreciate your help and insights on these topics!

Thank you!

Answer 1

[Gayathri]

Hi @hend,

Self-attention, spatial attention, and channel attention are all mechanisms used to enhance the performance of neural networks by focusing on important features, but they address different aspects of feature importance.

• Self-attention is primarily used to capture dependencies and relationships between elements in a sequence or set, regardless of their position.
• Spatial attention focuses on identifying which parts of a spatial structure (e.g., an image) are more important. It emphasizes certain spatial locations within the feature maps, allowing the model to concentrate on relevant regions.
• Channel attention mechanisms emphasize the importance of different feature maps.

To implement Spatial and Channel attention layers, you will have to define it as a custom layer in MATLAB.

To get more idea of how to build the custom layer for Spatial and Channel attention please refer to the following links to the questions in MATLAB answers.

https://www.mathworks.com/matlabcentral/answers/1599089-how-to-implement-spatial-attention-mechanism-in-deep-network-designer

https://www.mathworks.com/matlabcentral/answers/2150699-how-to-create-channel-attention-layer-in-matlab

Also, to implement the Spatial Attention layer as a custom layer, please refer to the following paper (especially Figure 3).

https://arxiv.org/pdf/1910.03151

Hope you find this information helpful!