  Visible-infrared person re-identification (VI-ReID) is a challenging and
essential task in night-time intelligent surveillance systems. Except for the
intra-modality variance that RGB-RGB person re-identification mainly overcomes,
VI-ReID suffers from additional inter-modality variance caused by the inherent
heterogeneous gap. To solve the problem, we present a carefully designed dual
Gaussian-based variational auto-encoder (DG-VAE), which disentangles an
identity-discriminable and an identity-ambiguous cross-modality feature
subspace, following a mixture-of-Gaussians (MoG) prior and a standard Gaussian
distribution prior, respectively. Disentangling cross-modality
identity-discriminable features leads to more robust retrieval for VI-ReID. To
achieve efficient optimization like conventional VAE, we theoretically derive
two variational inference terms for the MoG prior under the supervised setting,
which not only restricts the identity-discriminable subspace so that the model
explicitly handles the cross-modality intra-identity variance, but also enables
the MoG distribution to avoid posterior collapse. Furthermore, we propose a
triplet swap reconstruction (TSR) strategy to promote the above disentangling
process. Extensive experiments demonstrate that our method outperforms
state-of-the-art methods on two VI-ReID datasets.
