基于通道内截断的星载遥感图象精确码率控制方法

针对JPEG2000码率控制方法无法使压缩码流长度精确达到预设值，影响星载遥感系统缓存设计和控制、造成无用数据被纠错编码导致传输资源浪费等问题，提出了基于通道内截断的精确码率控制方法，将JPEG2000以通道为最小单位的码率控制延伸到通道内码率控制。先进行码率粗控制，再进行通道内截断，根据编码过程自适应地保留相对重要的通道数据，舍弃不重要的数据，最终实现精确码率控制。仿真结果表明，相对于JPEG2000码率控制的结果与预设码率相差可达上百字节，该方法在有所提高执行速度并保持图象恢复质量的前提下能够精确达到预设的码率，结果与预设码率完全一致。不仅能够解决上述问题，而且为地面接收的同步处理提供了方便。

An Inner-Pass Truncation Based Exact Rate Control Method for Satellite Onboard Remote Sensing Image

The rate control method of JPEG2000 can't ensure the length of JPGE2000 codestream to reach the predefined value exactly,which will affect the design and control method of satellite onboard memory and waste transmission resources because of correction coding of the useless data.In order to solve these problems,the exact rate control method based on inner-pass truncation is proposed.It extends from the traditional pass-based control to the inner-pass based control.After the rough rate control being carried out,the inner-pass truncation is performed.According to the coding process,the important part of pass data is self-adaptively preserved,while the less important part is discarded.And then the exact rate control is done.Experimental results show that,compared with the traditional rate control method of JPEG2000,whose results are different from the predefined value up to hundreds of bytes,the proposed method obtains the exact rate control with no difference.At the same time,the coding speed is increased and the quality of the decoded images is held.It not only can solve the problems mentioned above effectively,but also benefit the data synchronization on the ground.