Algorithm 3 Forward and Backward Projectors
Ray‐driven Projector
1: Bind a 3D image to the texture memory.
2: Assign a specific sinogram coordinate for each thread.
3: for each thread do
4: Calculate the coordinates of fan‐beam rays.
5: Add the interpolated voxel values along the ray.
6: Store the sum value.
7: end for
Voxel‐driven Backprojector
1: Bind the sinogram to the texture memory.
2: State Assign a specific voxel coordinate for each thread.
3: for each thread do
4: Calculate all angular sinogram positions.
5: Add sinogram values and store the sum value.
6: end for