Multiple Prompt Fusion for Zero-Shot Lesion Detection Using Vision-Language Models

The success of large-scale pre-trained vision-language models (VLM) has provided a promising direction of transferring natural image representations to the medical domain by providing a well-designed prompt with medical expert-level knowledge. However, one prompt has difficulty in describing the medical lesions thoroughly enough and containing all the attributes. Besides, the models pre-trained with natural images fail to detect lesions precisely. To solve this problem, fusing multiple prompts is vital to assist the VLM in learning a more comprehensive alignment between textual and visual modalities. In this paper, we propose an ensemble guided fusion approach to leverage multiple statements when tackling the phrase grounding task for zero-shot lesion detection. Extensive experiments are conducted on three public medical image datasets across different modalities and the detection accuracy improvement demonstrates the superiority of our method.