摘要
本文研究了一种简单有效的ＤＣＴ自适应图像码方法，它可应用于给定码率的静止图像压缩．本编码方法在进行“无死区”的线性量化时，通过调整图像的每个１６＊１６宏块的量化步距来完成“自适应性”，即：①量化步距随本宏块的活动性而变化．②量化步距同时受码率均衡缓存的反馈控制．在码率为０．４ｂｉｔ／Ｐｅｌ下，对于２５６＊２５６，８ｂｉｔ／Ｐｅｌ两幅黑白图像的实验结果仍有相当好的图像质量．
In this paper,we describe a simple and efficient image compression technique,which is an adaptive DCT coding of still images for constant bit-rate transmission and storage. In this coding scheme, linear quantization without'dead - zone' is used and the adaptivity achieved by adjusting the quantization step of each 16 * 16 MB in a image: (a)The step is feedback-controlled by a rate equalization buffer. (b)The step is adjusted with the activity o f the current MB. Fairly good results are demonstrated for coding of two 256 * 256,8bit/pel monochrome images at a rate of 0.4bit/pel.
