Gather-Excite

Gather-Excite (GE) is a spatial attention mechanism that gathers local spatial context and then excites (modulates) feature responses — extending the squeeze-and-excitation concept from channel attention to spatial attention by gathering spatial neighborhoods.

How Does Gather-Excite Work?

• Gather: Aggregate spatial context at multiple scales using depth-wise convolutions or average pooling at different resolutions.
• Excite: Use the gathered context to produce spatial attention weights.
• Modulate: Multiply feature maps by the spatial attention weights.
• Variants: GE-θ (parameterized gather), GE-θ+ (with skip), GE-θ- (lightweight).
• Paper: Hu et al. (2018).

Why It Matters

• Spatial SE: Extends the highly successful SE concept to the spatial dimension.
• Multi-Scale: The gathering operation captures context at multiple spatial scales.
• Complementary: Can be combined with channel attention (SE) for full channel+spatial attention.

Gather-Excite is spatial context for feature modulation — gathering neighborhood information to tell each location how important it is.