GetDRRSiddonJacobsRayTracing returns empty image for certain angles

I created a so-called “virtual C-arm” using the function GetDRRSiddonJacobsRayTracing Algirhtm [1], but for certain angles the resulting image is black. The following commands were used to generate the DRR’s. The angle difference is only 1 degree but one image is a normal DRR while the other image is all black.

Does anybody know why this happens? is there a solution to create DRR’s of all angles

getDRRSiddonJacobsRayTracing -rp 90 -rx 90 -ry 10 -rz 0 -t 0 147.0 -118.5 -iso 140 140 65 -res 0.5 0.5 -size 600 600 -o run1.tif CT.img = all black image
getDRRSiddonJacobsRayTracing -rp 90 -rx 90 -ry 9 -rz 0 -t 0 147.0 -118.5 -iso 140 140 65 -res 0.5 0.5 -size 600 600 -o run2.tif CT.img = normal DRR image

[1] [ITKTwoProjectionRegistration/GetDRRSiddonJacobsRayTracing.cxx at master · InsightSoftwareConsortium/ITKTwoProjectionRegistration · GitHub ]

@simon.rit might be able to answer.

No sorry. I don’t see anything wrong with your code and I would have to dig in the code to understand the problem… Maybe you can check if the transform defined in the code is meaningful by adding an itk::ResampleImageFilter? I would also write the image in float, before rescaling, to check that there is not something dense that comes in the field of view when you rotate by 1 degree which would perturbate the operation.

Thanks, I will look into it!