Lensless light-field imaging with flexible perspective selection
Publication Name
Proceedings of SPIE - The International Society for Optical Engineering
Abstract
The perspectives of light-field images taken by lens-based light-field camera are fixed due to the fixed position and size of lenslet. Unlike lens-based light-field imaging, lensless light-field imaging technologies encode light-field information of scene through a diffuser, and then reconstruct the light-field images by computational algorithms. In this paper, a commercial holographic diffuser is employed in the lensless light-field imaging system, and a flexible complementary segmentation method of sub-aperture region is proposed for the point spread function (PSF). The surface of the holographic diffuser is composed of relief microstructures, which are pseudo-random and non-periodic. Hence, any region of the holographic diffuser can encode and recover light information of object independently, just like sub-aperture imaging from corresponding perspective. Firstly, the PSF of lensless light-field imaging system is calibrated, and the encoded image of scene is also captured; after that, the PSF is divided into two complementary regions as sub-PSFs, corresponding to different sub-aperture regions; then sub-aperture images of scene are reconstructed with corresponding sub-PSFs through reconstruction algorithm, achieving light-field image of selected perspective; properly dividing the sub-PSF and reconstructing sub-aperture image, the sub-aperture image array of light-field can be obtained; with these light-field images, digital refocusing can be achieved finally. Different from existing segmentation method of PSF in lensless light-field imaging, the complementary segmentation method divides PSF into two sub-PSFs while these tow sub-PSFs are complementary to each other. This allows us to arbitrarily select the position and size of sub-PSF flexibly, namely flexible perspective selection. Meanwhile, decreasing the sub-aperture images to be reconstructed in algorithm can reduce error in reconstruction. Experiments show that, the complementary segmentation method can freely select the position and size of sub-aperture region while reducing the reconstruction error of lensless light-field imaging system significantly.
Open Access Status
This publication is not available as open access
Volume
12921
Article Number
129210A
Funding Number
ZDSYS20200107103001793
Funding Sponsor
National Natural Science Foundation of China