Image Captioning Method Based on CLIP-Combined Local Feature Enhancement and Multi-Scale Semantic Guidance

To address the issues of modeling the relationships between multiple local region objects in images and enhancing local region features, as well as mapping global image semantics to global text semantics and local region image semantics to local text semantics, a novel image captioning method based on CLIP and integrating local feature enhancement and multi-scale semantic guidance is proposed. The model employs ViT as the global visual encoder, Faster R-CNN as the local region visual encoder, BERT as the text encoder, and GPT-2 as the text decoder. By constructing a KNN graph of local image features, the model models the relationships between local region objects and then enhances the local region features using a graph attention network. Additionally, a multi-scale semantic guidance method is utilized to calculate the global and local semantic weights, thereby improving the accuracy of scene description and attribute detail description generated by the GPT-2 decoder. Evaluated on MSCOCO and Flickr30k datasets, the model achieves a significant improvement in the core metric CIDEr over established strong baselines, with 4.7% higher CIDEr than OFA on MSCOCO, and 16.6% higher CIDEr than Unified VLP on Flickr30k. Ablation studies and qualitative analysis validate the effectiveness of each proposed module.