感兴趣区域图像编码技术是数字图像压缩编码领域的研究热点。文中提出了一种基于JPEG2000标准的率失真斜率优化和系数移位相结合的感兴趣编码改进方法,它结合了两者编码方式的优势,并在率失真斜率优化算法中充分考虑到ROI区域的比例并影响率失真函数的加权值。该方法提高了图像编码的信噪比,支持多个感兴趣区域,并且ROI的形状不受限制。实验证明:该方法不仅在低码率条件下提高了感兴趣区域的信噪比,在高码率下整幅图像的信噪比也得到了改善。
The coding technology of ROI image is the hot topic in the digital image compression. It introduces an improved ROI image compression method based on JPEG2000 ,which combined the coefficients shift with rate-distortion optimization algorithm. This method takes the advantage of the two methods, considering sufficiently the proportion of the size of ROI in the rate-distortion optimization algorithm and influencing the PSNR. What' s more,it supports multi-ROIs and arbitrary shapes. Experimental results show that it improved the ROI' s PSNR in the low rate,and in the high bit rate the whole picture' s PSNR is also improved too.