  Binary silhouettes and keypoint-based skeletons have dominated human gait
recognition studies for decades since they are easy to extract from video
frames. Despite their success in gait recognition for in-the-lab environments,
they usually fail in real-world scenarios due to their low information entropy
for gait representations. To achieve accurate gait recognition in the wild,
this paper presents a novel gait representation, named Gait Parsing Sequence
(GPS). GPSs are sequences of fine-grained human segmentation, i.e., human
parsing, extracted from video frames, so they have much higher information
entropy to encode the shapes and dynamics of fine-grained human parts during
walking. Moreover, to effectively explore the capability of the GPS
representation, we propose a novel human parsing-based gait recognition
framework, named ParsingGait. ParsingGait contains a Convolutional Neural
Network (CNN)-based backbone and two light-weighted heads. The first head
extracts global semantic features from GPSs, while the other one learns mutual
information of part-level features through Graph Convolutional Networks to
model the detailed dynamics of human walking. Furthermore, due to the lack of
suitable datasets, we build the first parsing-based dataset for gait
recognition in the wild, named Gait3D-Parsing, by extending the large-scale and
challenging Gait3D dataset. Based on Gait3D-Parsing, we comprehensively
evaluate our method and existing gait recognition methods. The experimental
results show a significant improvement in accuracy brought by the GPS
representation and the superiority of ParsingGait. The code and dataset are
available at https://gait3d.github.io/gait3d-parsing-hp .
