<title>Rate-controlled near-lossless image codec based on visual perception and content adaptability</title>

Abstract

A content adaptive near lossless image codec is designed in this paper to accommodate a visual perception based rate control scheme. The near lossless codec is a modified version of JPEG-LS, in which the modification is typified by the addition of: (i) two levels of information loss distribution; (ii) line-fitting target prediction; and (iii) visual perception based rate control, implemented via quantization and redistribution of distortion. To minimise the possible excessive information loss being introduced during the rate control process, a technology of so-called moving-across-arrays is proposed to arrange the adjustment of distortion levels. Combined with the line-fitting based target prediction, the proposed scheme successfully controls the compression ratio within a limited range of targets, yet the decoded image quality is maintained competitive to JPEG-LS, the non-controlled one. Extensive experiments are carried out to show that the proposed scheme achieves effective rate control for a range of image samples and competitive image quality in terms of visual perception.