部分混合位平面位移的JPEG2000感兴趣区域图像编码

Partial Composite Bitplanes Shift Method for JPEG2000 Region-of-Interest Image Coding

针对JPEG2000图像编码标准中定义的两种感兴趣区域(ROI)编码方法的缺点和GPBShift算法的不足,提出一种新的感兴趣区域编码方法—部分混合位平面位移法(Partial Composite Bitplanes Shift method)PCBShift.本方法把ROI与背景区域(BG)划分为6部分,通过调整各部分的参数来实现位平面的位移。本方法不仅可以支持任意形状的感兴趣区域,而且可以任意调节感兴趣区域与背景区域的相对质量。实验结果表明:对用PCBShift方法重建图像的质量比用最大位移法(Maxshift method)和GPBShift算法,在相同解码率下有更好的图像质量,并且能根据不同优先级,在同一幅图像中对多感兴趣区域进行有效的编码。

The JPEG2000 image coding standard defines two kinds of region of interest （ROI） coding methods-the general scaling based method and the maximum shift（maxshift） method. Both of the two methods have their own＇s limitations. A new ROI coding method called Partial Composite Bitplanes Shift（PCBShift） was presented, which divided the region of interest（ROI） and the background into six parts. Through adjusting the parameters of the six parts, the shifted bitplanes were achieved. The PCBShift method not only supported arbitrarily shaped ROI coding without coding the shape, but also enabled the flexible adjustment of compression quality in ROI and background. Experimental results expatiated that the quality of reconstructed image of ROI was better than the one by the Maxshift method and GPBShift method at the same decoded bit rates, and can efficiently code multiple ROIs with different degrees of interest in an image.