Journal Article

Lensless light-field imaging through diffuser encoding

Cai Zewei, Osten, Wolfgang, Pedrini Giancarlo, Chen, Jiawei, Peng Xiang, Liu, Xiaoli

2020

Overview

Microlens array-based light-field imaging has been one of the most commonly used and effective technologies to record high-dimensional optical signals for developing various potential high-performance applications in many fields. However, the use of a microlens array generally suffers from an intrinsic trade-off between the spatial and angular resolutions. In this paper, we concentrate on exploiting a diffuser to explore a novel modality for light-field imaging. We demonstrate that the diffuser can efficiently angularly couple incident light rays into a detected image without needing any lens. To characterize and analyse this phenomenon, we establish a diffuser-encoding light-field transmission model, in which four-dimensional light fields are mapped into two-dimensional images via a transmission matrix describing the light propagation through the diffuser. Correspondingly, a calibration strategy is designed to flexibly determine the transmission matrix, so that light rays can be computationally decoupled from a detected image with adjustable spatio-angular resolutions, which are unshackled from the resolution limitation of the sensor. The proof-of-concept approach indicates the possibility of using scattering media for lensless four-dimensional light-field recording and processing, not just for two- or three-dimensional imaging.Imaging: Lensless light-field imaging lays foundations for new applicationsBy replacing lenses with a diffuser in light-field imaging, scientists could expand its use in applications ranging from light-field microscopy and synthetic aperture imaging to visual odometry. Microlens array-based light-field imaging is one of the most commonly used technologies to record high-dimensional optical images. However, they suffer from a trade-off between the spatial and angular resolutions. Xiaoli Liu and colleagues from Shenzhen University in China, in collaboration with researchers from the University of Stuttgart in Germany, have now developed a novel technique that uses a diffuser to angularly couple incident light rays into a detected image without the need for a lens. The diffuser allows each sub-beam emitted by a point source to form a distinguishable sub-image covering a region on the sensor and could lead to lensless four-dimensional light-field imaging.

• Publisher: Springer Nature B.V
• Subject: Light / Microscopes