A compact wavelet index for retrieval in image database

In this paper, we present an algorithm to build an index for image retrieval that heavily exploits the wavelet multi-resolution decomposition. The index can be constructed using alternative levels in the multi-resolution decomposition; it is based on the correlation between the scaled-down approximation image and its reconstruction obtained using only one level in the hierarchy of detail images. The method has been tested on RBG and YUV color spaces on a database of 167 images with good results. The effect of white Gaussian noise is negligible, because the wavelet approximation smooths off this kind of noise. The method is more sensitive to geometric distortion noise.