Diffraction-Compensating Coded Aperture for Inspection in Manufacturing

In this paper, we adopt the coded aperture technique to the alignment process for industrial machinery. As a special setting for assembly and inspection, such machinery uses an illumination of narrow wavelength range for imaging with less aberration. This leads to significant influence of light diffraction on the image restoration. Although the diffraction was treated as negligible in most previous studies of coded aperture since they were carried out for natural images, the aperture patterns of them do not achieve enough accuracy for the alignment. We optimize the aperture pattern by performing a simulation of light diffraction, and we experimentally show that it achieves better performance in the alignment.