JPEG-LS

Abstract

DefinitionJPEG-LS is an image compression standard (ISO/IEC-14495-1 / ITU-T Rec. T.87) designed to provide effective lossless and near lossless compression of continuous-tone, gray scale and color still images.Near lossless, in this context, means a guaranteed maximum error between the original image data and the reconstructed image data. One of its main potential driving forces is the compression of medical images without any quality loss.The core algorithm behind JPEG-LS is called LOw COmplexity LOssless COmpression for Images (LOCO-I), proposed by Hewlett-Packard [1–3]. LOCO-I builds upon a concept known as context modeling. The main idea behind context modeling is to take advantage of the structure in the input source, modeled in terms of conditional probabilities of what pixel values follow from each other in the image (Fig 1).JPEG-LS. Figure 1.JPEG-LS/LOCO-I context model: pixel value x is predicted based on the values of a, b, c, and d.LOCO-I has three main components: