ICPL-ReID: Identity-Conditional Prompt Learning for Multi-Spectral Object Re-Identification

TL;DR

This paper introduces ICPL, a novel identity-conditional prompt learning framework leveraging CLIP for multi-spectral object re-identification, effectively addressing spectral modality differences and improving performance across multiple benchmarks.

Contribution

The paper proposes a new ICPL framework that uses online prompt learning, identity prototypes, and multi-spectral adapters to enhance spectral feature alignment and re-identification accuracy.

Findings

Outperforms state-of-the-art methods on 5 benchmarks.

Effectively handles spectral modality differences.

Improves spectral feature alignment and re-identification accuracy.

Abstract

Multi-spectral object re-identification (ReID) brings a new perception perspective for smart city and intelligent transportation applications, effectively addressing challenges from complex illumination and adverse weather. However, complex modal differences between heterogeneous spectra pose challenges to efficiently utilizing complementary and discrepancy of spectra information. Most existing methods fuse spectral data through intricate modal interaction modules, lacking fine-grained semantic understanding of spectral information (\textit{e.g.}, text descriptions, part masks, and object keypoints). To solve this challenge, we propose a novel Identity-Conditional text Prompt Learning framework (ICPL), which exploits the powerful cross-modal alignment capability of CLIP, to unify different spectral visual features from text semantics. Specifically, we first propose the online prompt learning using learnable text prompt as the identity-level semantic center to bridge the identity semantics of different spectra in online manner. Then, in lack of concrete text descriptions, we propose the multi-spectral identity-condition module to use identity prototype as spectral identity condition to constraint prompt learning. Meanwhile, we construct the alignment loop mutually optimizing the learnable text prompt and spectral visual encoder to avoid online prompt learning disrupting the pre-trained text-image alignment distribution. In addition, to adapt to small-scale multi-spectral data and mitigate style differences between spectra, we propose multi-spectral adapter that employs a low-rank adaption method to learn spectra-specific features. Comprehensive experiments on 5 benchmarks, including RGBNT201, Market-MM, MSVR310, RGBN300, and RGBNT100, demonstrate that the proposed method outperforms the state-of-the-art methods.