中文摘要：

为了实现感兴趣区域（Region of Interest,ROI）的重建,使用了一种利用微分和有限希尔伯特变换的局部特性的反投影滤波（back projection fiheration,BPF）算法.该算法是一种理论上精确的ROI重建算法,首先对仅仅覆盖ROI区域的投影数据微分,然后反投影到ROI区域,最后沿着覆盖ROI区域的PI线做有限希尔伯特滤波得到ROI图像.仿真实验表明BPF算法和经典的滤波反投影（Filtered Back Projection,FBP）算法的全局重建的精度基本相同,但该算法可以实现精确的ROI重建,而FBP算法因不具有局部特性,不能实现ROI重建.在实现有限希尔伯特变换时,采用了加权希尔伯特变换的方法,有效地避免了图像两边的亮条伪像.

英文摘要：

In order to realize the reconstruction of the Region of Interest（ROI） ,a back projection filter（BPF） algorithm by using the local properties of differential and limited Hilbert transform is proposed in this paper. It is an accurate algorithm,firstly,differential the projection data only cover the ROI area,then do back projection to the ROI area,lastly do limited Hilbert filter to get the R0I image along the PI line covered ROI area. The simulation demonstrates that BPF and filter back projection（FBP） algorithm＇s accuracy of whole reconstruction is substantially the same,but BPF algorithm can re- alize the accurate ROI reconstruction,while the FBP can＇t do it by it have not local properties. The paper using a weighted Hilbert transform method in realizing the limited Hilbert transform, since that it can avoid the bright side of image artifacts effectively.