经典的滤波算法：1、限幅滤波法2、中位值滤波法3、算术平均滤波法4、递推平均滤波法5、中位值平均滤波法6、限幅平均滤波法7、一阶滞后滤波法-One of the conventional reconstruction techniques of CT is the filtered backprojection method which has little complexity and high resolution, but has not locality properly