Progressive Semantic Reconstruction Network for Weakly Supervised Referring Expression Grounding

Weakly supervised Referring Expression Grounding (REG) aims to localize the target entity in an image based on a given expression, where the mapping between image regions and expressions is unknown during training. It faces two primary challenges. Firstly, conventional methods involve selecting regions to generate reconstructed texts for computing the backpropagation loss between regions and expressions. However, semantic deviations in text reconstruction may result in significant cross-modal bias, leading to substantial losses even in cases of correctly matched regions. Secondly, the absence of region-level ground truth in weakly supervised REG results in a lack of stable and reliable supervision during training. To tackle these challenges, we propose a Progressive Semantic Reconstruction Network (PSRN), which utilizes a two-level matching-reconstruction process based on the key triad and adaptive phrases, respectively. We leverage progressive semantic reconstruction with a three-staged training strategy to mitigate the deviations in the reconstructed texts. Additionally, we introduce a Constrained Interactions operation and an Attention Coordination mechanism to facilitate additional bidirectional supervision between the two matching processes. Experiments on three benchmark datasets of RefCOCO, RefCOCO+ and RefCOCOg demonstrate that the proposed PSRN has the competing results. Our source code will be released at https://github.com/5jiahe/psrn.