Supervised Contrastive Vehicle Quantization for Efficient Vehicle Retrieval

Abstract

This paper considers large-scale efficient vehicle re-identification (Vehicle ReID). Existing works adopting deep hashing techniques function by projecting vehicle images into compact binary codes in the Hamming space. Since Hamming distance is less distinct, a considerable amount of discriminative information will be lost, leading to degraded retrieval performances. Inspired by the recent advancements in contrastive learning, we put forward the very first product quantization based framework for large-scale efficient vehicle re-identification: Supervised Contrastive Vehicle Quantization (SCVQ). Specifically, we integrate the product quantization process into deep supervised learning by designing a differentiable quantization network. In addition, we propose a novel supervised cross-quantized contrastive quantization (SCQC) loss for similarity-preserving learning, which is tailored for the asymmetric retrieval in the product quantization process. Comprehensive experiments on two public benchmarks have evidenced the superiority of our framework against the state-of-the-arts. Our work is open-sourced at https://github.com/chrisbyd/ContrastiveVehicleQuant