二维图像的投影和图像重建，直接傅里叶反变换法，先反投影后滤波，先滤波后反投影，卷积反投影(Two dimensional image projection and image reconstruction, direct Fourier inverse method, first backprojection, after filtering, first filter, back projection, convolution back projection)

平行光反投影，matlab算法实现的算法(Parallel light backprojection and matlab algorithm implementation)