W-transform Method for Feature-oriented Multiresolution Image Retrieval

We present a local-feature-oriented image indexing and retrieval method based on Kwong and Tang's W-transform. Multiresolution histogram comparison is an eeective method for content-based image indexing and retrieval. However, most recent approaches perform multiresolution analysis for whole images but do not exploit the local features present in the images. Since W-transform is featured by its ability to handle images of abitrary size, with no periodicity assumptions , it provides a natural tool for analyzing local image features and building indexing systems based on such features. In our approach, the histograms of the local features of images are used in the indexing system. The system not only can retrieve images that are similar or identical to the query images but also can retrieve images that contain features speciied in the query images, even if the retrieved images as a whole might be very diierent from the query images. The local-feature-oriented method also provides a speed advantage over the global multiresolution histogram comparison method. The 1 feature-oriented approach is expected to be applicable in managing large-scale image systems such as video databases and medical image databases.