斜变滤波器时域加窗对图像重建的影响  

Impact of Time Domain Window-adding for the Ramp Filter on Image Reconstruction

作　　者：乔志伟[1] 

机构地区：[1]中北大学电子与计算机科学技术学院,山西太原030051

出　　处：《计量学报》2014年第3期268-271,共4页Acta Metrologica Sinica

基　　金：基金项目：国家自然科学基金（61071193,61171179）

摘　　要：提出了斜变滤波器的单位脉冲响应的时域加窗方法。斜变滤波器的单位脉冲响应应取奇数个点并偶对称，以保证其严格零相位。可以用来截取单位脉冲响应的窗函数有矩形窗、三角窗、汉宁窗、海明窗、布莱克曼窗等。仿真实验表明，矩形窗精度最好，三角窗因过度地压低了第一旁瓣，精度最差，其余窗对应的CT图像的精度介于两者之间。在对斜变滤波器的单位脉冲响应截断时应该使用矩形窗。The time domain window-adding method for the unit impulse response of the ramp filter is proposed, the unit impulse response of the ramp filter should be symmetrical and its length should be odd number to ensure that it is strict zero-phase. There are many windows to truncate the unit impulse response, for example, rectangle window, triangle window, Hanning window, Hamming windows, Blackman window etc. The simulation experiment demonstrates that the rectangle window is the best and the triangle window is the worst, for the triangle window depresses the first side petal overly. The precision of the CT images reconstructed by the others windows is in-between. The rectangle window should be used when the unit impulse response of the ramp filter is been truncated.

关 键 词：计量学 斜变滤波器 窗函数 图像重建 滤波反投影算法 

分 类 号：TB973[一般工业技术—计量学]