Check image compression: a comparison of JPEG, wavelet and layeredcoding methods

摘要

An emerging trend in the banking industry is to digitize checksfor storage and transmission. An immediate requirement for efficientstorage and transmission is check image compression. General purposecompression algorithms such as JPEG and wavelet-based methods produceannoying ringing and blocking artifacts at high compression ratios. Alayered approach to check image compression is proposed, based on whicha check image is represented in several layers. The first layerdescribes the foreground map; the second layer specifies the gray levelsof foreground pixels; the third layer is a lossy representation of thebackground image; and the fourth layer describes the error between theoriginal and the reconstructed image based on the first three layers.The layered coding approach produces images of better quality thantraditional JPEG and wavelet coding methods, especially in theforeground, i.e., the text and graphics. In addition, this approachallows progressive retrieval or transmission of different image layers