High-resolution images enable neural networks to learn richer visual representations. However, this improved performance comes at the cost of growing computational complexity, hindering their usage in latency-sensitive applications. As not all pixels are equal, skipping computations for less-important regions offers a simple and effective measure to reduce the computation. This, however, is hard to be translated into actual speedup for CNNs since it breaks the regularity of the dense convolution workload. In this paper, we introduce SparseViT that revisits activation sparsity for recent window-based vision transformers (ViTs). As window attentions are naturally batched over blocks, actual speedup with window activation pruning becomes possible: i.e., ~50% latency reduction with 60% sparsity. Different layers should be assigned with different pruning ratios due to their diverse sensitivities and computational costs. We introduce sparsity-aware adaptation and apply the evolutionary search to efficiently find the optimal layerwise sparsity configuration within the vast search space. SparseViT achieves speedups of 1.5x, 1.4x, and 1.3x compared to its dense counterpart in monocular 3D object detection, 2D instance segmentation, and 2D semantic segmentation, respectively, with negligible to no loss of accuracy.

本文提出了SparseViT，通过窗口激活剪枝技术对最近的基于窗口的视觉变换器(VITs)进行活化稀疏化处理，通过稀疏感知的调整和进化搜索，实现不同层次适应不同的剪枝比率优化。SparseViT在不降低准确性的前提下，分别在单眼3D目标检测、2D实例分割和2D语义分割中实现了1.5x、1.4x和1.3x的速度提升。

SparseViT：重新审视激活稀疏性，为高效高分辨率视觉变换器提供支持