Lensless polarization camera for single-shot full-Stokes imaging

Abstract

Lensless cameras have recently emerged as a compact imaging system based on computational imaging with various multiplexing capabilities. Here, we propose a compact and low-cost lensless camera that enables snapshot full-Stokes polarization imaging. While polarization imaging provides additional contrast based on the birefringence and surface properties of the object, most polarization cameras require bulky hardware or are limited to measuring only the linear polarization information. Our device, composed of a phase mask, a polarization-encoded aperture, and a regular image sensor, performs compressed imaging to recover linear as well as circular polarization information of the scene from single image capture. We demonstrate the full-Stokes imaging capabilities of our device and describe the image reconstruction and calibration processes.

Advances in Mask-Modulated Lensless Imaging

“…Through the transmission matrix, the rays can be computationally decoupled from the detected image, and the spatial and angular resolutions can be adjusted, breaking the resolution limit of the sensor. Baek et al [23] proposed a lensless polarization camera that can achieve full-Stokes polarization imaging in a single shot, and the full-Stokes polarization imaging can provide additional contrast based on the birefringence and surface characteristics of objects. Moreover, a diffuser-encoded light-field transmission model is established, and an image reconstruction and calibration process is designed.…”

“…Moreover, the SweepCam [16], FAZ [12], and lensless three-dimensional imaging system [17] were designed by using amplitude-modulated masks. In 2022, the compound eye microsystem [15] and lensless polarization camera [23] were devised for amplitude and phase-modulated lensless imaging systems, accordingly. In 2024, Chen et al developed a learnable phase-modulated lensless camera based on the concepts of deep optics and diffractive optical neural networks [24].…”

Multilayer lensless camera for improving the condition number

“…By eliminating the lens, it is possible to realize a significant thinning of the camera's optical system. Additionally, by actively using the degrees of freedom of the system that includes optical encoding, computational lensless imaging is also used to compactly realize three-dimensional (3D) imaging [5,6], multispectral imaging [7,8], polarization imaging [9,10], diffractive neural network [11,12], and privacy-protected imaging [13][14][15].…”

Non-Line-of-Sight Full-Stokes Polarimetric Imaging with Solution-Processed Metagratings and Shallow Neural Networks

“…Today, there is a significant demand for full-Stokes imaging systems with compact sizes and reduced fabrication costs. One approach is to make use of the speckles , of the reflected or scattered light, which encode polarization information. − Another approach is to utilize metasurfaces, − which have been designed to spatially separate different polarization states of light and have thus been used in S 3 detection, − polarimetry, , and full-Stokes imaging. − There are also other approaches such as lensless polarization imaging, , deep learning imaging, , and so on. Despite those efforts, unresolved technical challenges remain with each of these approaches: polarimetric speckle imaging generally involves bulky volumes and moving optical parts; metasurfaces, while compact, are generally expensive to fabricate, especially for mass production; , lensless and deep learning methods often entail real-time imaging delays and employ linear-polarization cameras.…”