Experimental Studies on a Compact Storage Scheme for Wavelet-Based Multiresolution Subregion Retrieval

Wavelet transforms, when combined with quantization and a suitable encoding, can be used to compress images effectively. In order to use them for image library systems, a compact storage scheme for quantized coefficient wavelet data must be developed with a support for fast subregion retrieval. We have designed such a scheme and in this paper we provide experimental studies to demonstrate that it achieves good image compression ratios, while providing a natural indexing mechanism that facilitates fast retrieval of portions of the image at various resolutions. 1 Introduction Wavelet based algorithms have become popular for image compression. These typically involve three steps: (i) the application of a wavelet transform to an image to create coefficient matrices (ii) the quantization of these floating point matrices to create integer matrices, and (iii) encoding the quantized matrices to obtain the compressed image. The original image can be reconstructed by reversing the steps mention..