An Image Retrieval Method Based on Hu Invariant Moment and Improved Annular Histogram

摘要

Image retrieval methods based on annular histogram of feature points are calculation efficient, invariant to image rotation and translation transform. However, these methods have two main disadvantages. One is that the annular histogram can't describe the spatial distribution of feature points accurately, thus different images may have similar annular histogram. Another one is the methods based on feature points can not describe the shape information of object. These disadvantages affect the retrieval accuracy to a certain extent. In this paper, an image retrieval method based on Hu invariant moments and improved annular histogram is proposed. Firstly, edge of image is detected and feature points are calculated based on the edge curvature. Then, image features are described based on both the edge and points. Annular histogram combined with standard deviation ellipse method is used to describe the spatial distribution of feature points. Hu invariant moment of the edge is used to represent the object's shape information. Finally, the similarity is measured based on both the point feature and the shape feature. Experiment results show that the proposed method can improve the image retrieval precision effectively.