Multi-layer lensless camera for improving the condition number

Computational lensless imaging is a technology that realizes the thinning of the optical system by replacing optical imaging with image reconstruction processing. While the conventional optical design used a single coded mask and an image sensor, recent studies have proposed optical designs that use multiple stacked coded apertures for multidimensional imaging and wide-field imaging. In this study, we investigate the effect of the multi-layering of the coded aperture on the performance of two-dimensional spatial imaging. We demonstrate through simulations and optical experiments that the multi-layering of the coded aperture improves the condition number of the transmission matrix of the optical system, and as a result, improves the accuracy of image reconstruction in lensless imaging.