Sinograms calculator for 4D phase CT

I am posting here the sinograms calculator for 4D phase CT.

I am posting here sinograms calculator for 4D phase CT. The input data should be series of differential phase images from 1 (no_image_start) to 1000 images (no_image_stop). One differential phase image is named as dph_000001.raw, where 'dph' is the root image name and numbering contains 6 digits. Empty space in image number is filled with zeros. One differential phase image has size 1536 x 512 pixels. It is encoded in double or 64 bit real numbers with little endian byte order. As differential phase images has 512 rows, the sinogram can be calculated for slice 1 until 512. The sample was rotated in such a way that 400 projections correspond to the sample rotation from 0 degrees to 180 degrees (from 0 rad to pi). Therefore, single sinogram contains 400 rows, because of 400 projections per 180 degrees rotations, and 1536 columns or points, which is the size of the differential phase images in horizontal direction. I attach to the m-script also sinogram <sino_000001_000400.raw>. It contains 400 projectiosn of polypropylene sample taken at 400-th slice. You can open example sinogram in ImageJ in Import -> Raw -> 64 bit real, Width=1536, Height=400, little-endian byte order. This sinogram calculator calculates sinograms from fi to fi+180 degrees. The fi is the step in reconstruction. In my program angular step or shift in reconstruction or fi angle is defigned through variable step_shift. The step_shift is for example 10 images. It means 10 images divided by 400 images per period is 0.025. It means that 0.025 * 180 degreees = 4.5 degrees is the sample rotation step in reconstruction in 4D phase CT. The program also uses linear background subtraction from single projection. It takes 20 points from the left (first 20 points, region 1) and 20 points from right (last 20 points, region 2) and put linear function throught points. The program uses for that polyfit Matlab function and also polyval.