Projection and reconstruction method of industrial CT for small module spur gears

Abstract The industrial x-ray Computed Tomography (ICT) is increasingly applied in the manufacturing industry for dimensional quality control especially in gear industry for the plastic small module gears. To evaluate the measured gear and analysing the measurement uncertainty including Monte Carlo simulations, it is necessary to establish CT projection and reconstruction image for the measured gear. The mathematical model of the projected image is established for each part including tooth root, involute tooth body and tooth root fillet, and then the end section projection algorithm is obtained by the combination. The projection value of the gear end section at different rotation angles are simulated by MATLAB, which is combined to be a grayscale image of the projection image. Based on the filtered back-projection algorithms, the reconstruction image is created, which is binarized to get the gear end section data. The simulation results are verified to be close to the results by Geant4. The algorithms proposed is significant to the application of gear measurement in industrial CT, which is also helpful for other applications for complex surface parts.