Tree-Structured Kronecker Convolutional Network for Semantic Segmentation

Most existing semantic segmentation methods employ atrous convolution to enlarge the receptive field of filters, but neglect partial information. To tackle this issue, we firstly propose a novel Kronecker convolution which adopts Kronecker product to expand the standard convolutional kernel for taking into account the partial feature neglected by atrous convolutions. Therefore, it can capture partial information and enlarge the receptive field of filters simultaneously without introducing extra parameters. Secondly, we propose a Tree-structured Feature Aggregation (TFA) module which follows a recursive rule to expand and forms a hierarchical structure. Thus, it can naturally learn representations of multi-scale objects and encode hierarchical contextual information in complex scenes. Finally, we design a Tree-structured Kronecker Convolutional Network (TKCN) which employs Kronecker convolution and TFA module. Extensive experiments on three datasets, PAS-CAL VOC 2012, PASCAL-Context and Cityscapes, verify the effectiveness of our proposed approach.