Viewpoint Transform Matching model for person re-identification

Person re-identification is a challenging problem that aims at matching persons across multiple non overlapping cameras. Previous works on person re-identification mainly focus on solving the problems caused by pose variations, backgrounds, and occlusion while ignoring the viewpoint variations. To address the viewpoint problem, we propose a Viewpoint Transform Matching (VTM) model, which reduces the inference of viewpoints by feature-level viewpoint transformation. Overall, we design a framework by using viewpoint specific branches to separately extract the representation of different viewpoints. Specifically, we first select the branch for an input image, according to its viewpoint information. In the branch, we transform the feature to other viewpoints by establishing a mutually transformable connection between the features of different viewpoints. To suppress the interference among viewpoints, we propose a viewpoint transform classifier module to independently train a classifier for each viewpoint. To improve the effectiveness of the transform, we propose a viewpoint transform loss to guarantee the consistency of the original features and the transformed features. Experiments conducted on Market-1501, DukeMTMC-reID and CUHK03 show the effectiveness of the proposed method. (c) 2021 Elsevier B.V. All rights reserved.