Precise Rate Control Of JPEG-LS

JPEG-LS is the ISO/ITU standard for lossless and near-lossless compression of continuous-tone images approved in1998. Compare with other compression techniques, JPEG-LS almost performs best at high bit rate with low complexity and fast computation speed. However, in the transmission process especially in satellite applications, the encoder output rate must match with the limited channel bandwidth. In this situation, uncontrolled rate would lead to serious consequences, JPEG-LS can not control rate precisely in the near-lossless compression, which limits the applications of JPEG-LS.This Thesis introduced the backgrounds of static image compression standards, analyzed some typical coding algorithms of JPEG-LS and the theorems of rate distortion. First of all, the Thesis presented the JPEG-LS standard and Lagrange algorithm to find the extreme value. Second, the thesis studied the trellis coded quantization that uses rate control algorithm based on rate distortion and Lagrange algorithm. To solve the rate control problem of JPEG-LS, the thesis proposed a precise rate control algorithm for JPEG-LS in which the rate control algorithm used in trellis coded quantization is combined with JPEG-LS algorithm.At the end of this thesis, the performance of proposed rate control algorithm was assessed through a comparison with JPEG-LS dynamic rate control algorithm and JPEG2000standard. And the experimental results demonstrate that the proposed rate control algorithm could precisely control rate for JPEG-LS and the comparable performance could be also achieved.