ACSiam: Asymmetric convolution structures for visual tracking with Siamese network

Object trackers based on Siamese network usually transform the tracking task into a matching problem between the candidate samples and the target template. However, with the increasing depth and width of backbone networks, researches on Siamese trackers using backbone networks are not very advanced. Therefore, it is necessary for us to further investigate the characteristics of backbone network. As a fact, the ability of backbone network to extract features can directly determine the performance of object tracker. Given this, in this paper, we first propose an asymmetric convolutional network to improve the representational capability of backbone network. And then, the strip convolution is employed to enhance the operational capability of square kernel convolution in the backbone network. Besides, we also construct a novel module named Feature Dropblock (i.e., FD) to simulate the occlusion of hidden space, which goal is to improve the performance of backbone network in the target tracking under occlusion. To demonstrate the effectiveness of the proposed tracker, extensive ablation studies are conducted. Better results are obtained on the tracking benchmarks OTB100 and VOT2018, compared to other state-of-the-art trackers.