Threefold Encoder Interaction: Hierarchical Multi-Grained Semantic Alignment for Cross-Modal Food Retrieval

Current cross-modal food retrieval approaches focus mainly on the global visual appearance of food without explicitly considering multi-grained information. Additionally, direct calculation of the global similarity of image-recipe pairs is not particularly effective in terms of latent alignment, which suffers from mismatch during the mutual image-recipe retrieval process. This paper proposes a threefold encoder interaction (TEI) cross-modal food retrieval framework to maintain the multi-granularity of food images and the multi-levels of textual recipes to address the aforementioned challenges. The TEI framework comprises an image encoder, a recipe encoder, and a multi-grained interaction encoder. We simultaneously propose a multi-grained relation-aware attention (MRA) embedded in the multi-grained interaction encoder to capture multi-grained food visual features. The multi-grained interaction similarity scores are calculated to better establish the multi-grained correlation between recipe and image entities based on the extracted hierarchical textual and multi-grained visual features. Finally, a hierarchical multi-grained semantic alignment loss is designed to supervise the whole process of cross-modal training using the multi-grained interaction similarity scores. Extensive qualitative and quantitative experiments on the Recipe1M dataset have demonstrated that the proposed TEI framework achieves multi-grained semantic alignment between image and text modalities and is superior to other state-of-the-art methods in cross-modal food retrieval tasks.