Attention Model Based SIFT Keypoints Filtration for Image Retrieval

Effective feature extraction is a fundamental component of content-based image retrieval. Scale Invariant Feature Transform (SIFT) has been proven to be the most robust local invariant feature descriptor. However, SIFT algorithm generates hundreds of thousands of keypoints per image, and most of them comes from background. This has seriously affected the application of SIFT in real-time image retrieval. This paper addresses this problem and proposes a novel method to filter the SIFT keypoints using attention model. Based on visual attention analysis, all of the keypoints in an image are ranked with their attention saliency, and only the most distinctive keypoints will be reserved. Then we use Bag of words to efficiently index these features. Experiments demonstrate that the attention model based SIFT keypoints filtration algorithm provides significant benefits both in retrieval accuracy and matching speed.