Considering the speciality of communication channel and the natures of image sources ,based on the study of the need of network communication and JPEG standard ,JPEG algorithm is improved and an adaptive bit-rate control method is given.

• 结合信道特性和图象信源特性 ；在研究网络通信需求和JPEG标准的基础上 ；对JPEG算法进行了改进 ；使之适于网络传输 ；并给出了一种自适应的码流控制编码方法 .