DenoDet: Attention as Deformable Multi-Subspace Feature Denoising for Target Detection in SAR Images

TL;DR

DenoDet introduces a frequency domain attention mechanism and deformable subspace processing to improve SAR target detection by effectively denoising and preserving subtle target details amidst speckle noise.

Contribution

The paper proposes DenoDet, a novel SAR detection network with a frequency domain attention module and deformable subspace grouping, enhancing detection accuracy over existing methods.

Findings

Achieves state-of-the-art results on multiple SAR datasets.

Effectively denoises speckle noise while preserving target details.

Demonstrates robustness across heterogeneous terrains.

Abstract

Synthetic Aperture Radar (SAR) target detection has long been impeded by inherent speckle noise and the prevalence of diminutive, ambiguous targets. While deep neural networks have advanced SAR target detection, their intrinsic low-frequency bias and static post-training weights falter with coherent noise and preserving subtle details across heterogeneous terrains. Motivated by traditional SAR image denoising, we propose DenoDet, a network aided by explicit frequency domain transform to calibrate convolutional biases and pay more attention to high-frequencies, forming a natural multi-scale subspace representation to detect targets from the perspective of multi-subspace denoising. We design TransDeno, a dynamic frequency domain attention module that performs as a transform domain soft thresholding operation, dynamically denoising across subspaces by preserving salient target signals and attenuating noise. To adaptively adjust the granularity of subspace processing, we also propose a deformable group fully-connected layer (DeGroFC) that dynamically varies the group conditioned on the input features. Without bells and whistles, our plug-and-play TransDeno sets state-of-the-art scores on multiple SAR target detection datasets. The code is available at https://github.com/GrokCV/GrokSAR.