SDPT: Semantic-Aware Dimension-Pooling Transformer for Image Segmentation

Image segmentation plays a critical role in autonomous driving by providing vehicles with a detailed and accurate understanding of their surroundings. Transformers have recently shown encouraging results in image segmentation. However, transformer-based models are challenging to strike a better balance between performance and efficiency. The computational complexity of the transformer-based models is quadratic with the number of inputs, which severely hinders their application in dense prediction tasks. In this paper, we present the semantic-aware dimension-pooling transformer (SDPT) to mitigate the conflict between accuracy and efficiency. The proposed model comprises an efficient transformer encoder for generating hierarchical features and a semantic-balanced decoder for predicting semantic masks. In the encoder, a dimension-pooling mechanism is used in the multi-head self-attention (MHSA) to reduce the computational cost, and a parallel depth-wise convolution is used to capture local semantics. Simultaneously, we further apply this dimension-pooling attention (DPA) to the decoder as a refinement module to integrate multi-level features. With such a simple yet powerful encoder-decoder framework, we empirically demonstrate that the proposed SDPT achieves excellent performance and efficiency on various popular benchmarks, including ADE20K, Cityscapes, and COCO-Stuff. For example, our SDPT achieves 48.6% mIOU on the ADE20K dataset, which outperforms the current methods with fewer computational costs. The codes can be found at https://github.com/HuCaoFighting/SDPT.