Differentiated Backprojection Reconstruction Method for Square Cross-section FOV Rotational CL

With advancements in modern industry, computed tomography (CT) has played a significant role in nondestructive testing. However, owing to the limitations in the imaging field of view and X-ray penetration capability, CT faces challenges in the scanning and imaging of plate-like objects. To inspect plate-like objects, computer lithography (CL) has been developed by modifying the scanning geometry and reconstruction algorithms. CL reconstruction methods are inspired by CT reconstruction techniques and include analytical and iterative reconstruction methods. Filtered backprojection algorithms are fast, but often result in significant discrepancies from the true values, and iterative methods, although more accurate than analytical reconstruction, are usually time-consuming. This study draws on the differentiated backprojection (DBP) reconstruction method of circular trajectory fan-beam CT to derive a DBP reconstruction method for a square cross-sectional field-of-view (FOV) rotational CL. Using both simulated data and actual printed circuit board scanning data for reconstruction, the image quality of the DBP method was found to be similar to that of the filtered back projection algorithm, with certain advantages in addressing projection truncation challenges.