X-ray Transform and Reconstruction: stomach

Reading Image	Combined Image
Original Grayscale Image	X-ray transform
Unfiltered Backprojection	Reconstruction, i.e., Filtered Backprojection
"Unfiltered back projection" is called "Back Projection" which is mathematically the dual X-ray transform. "Filtered back projection" is so-called the reconstruction formula for the X-ray transform mathematically, that is, the back projection applied by the filter which is mathematically the square root of the nonnegative Laplacian on the plane.