sixth code

% determine distance from fan-beam vertex to center of rotation
distance = info_fixed1.DistanceSourceToDetector / info_fixed1.PixelSpacing(1);
center = size(img_data, 1) / 2; % assume center of rotation is in the middle of the image

% compute fanbeam projections
FB_theta = 0:179; % projection angles in degrees
FB_proj_LR = fanbeam(img_data, distance, 'FanSensorGeometry', 'line', '