Comparison of the image distortion correction methods for an X-ray digital tomosynthesis system

Abstract

X-ray digital tomosynthesis (DT) is very useful to PCB inspection because it can obtain a cross-sectional image of a local inspection area quickly. The image intensifier, which is usually used in DT, distorts X-ray images in shape and intensity, Therefore, image distortion correction is one of the most important issues in realizing DT system. In this paper, two image distortion correction methods for an X-ray DT system are presented and their performances are compared. The first method is to use a simplified distortion model by a distance ratio function in intensity correction, and by 2D point mapping polynomials in shape correction. The second method is to use a general polynomial distortion model. The experimental results show a great improvement of the second method in compensation speed and accuracy. © Springer-Verlag Berlin Heidelberg 2005.