The method of high-accuracy 3D reconstruction for oblique X-ray CT images

X-ray CT system for industrial inspection has some problems when it inspects flat objects. The problems are expansion rate and contrast. We previously implemented an oblique X-ray CT system, and found those problems were almost solved and that vertical accuracy was comparatively low. We now intend to improve the vertical accuracy by implementing extra two-arc cone-beam X-ray scan. The two-arc scan is for compensating the lack of data from the conventional oblique scan. The overall reconstruction algorithm is based on inverse Radon transform and Grangeat´s formula. In order to evaluate the accuracy of reconstructed images quantitatively, the computer simulation using a BGA phantom was implemented. Through the study it was revealed that the proposed method can compensate the previous reconstruction accuracy, and that proper distribution from both oblique scan and two-arc scan is needed for the correct reconstruction.