Aperture-encoded snapshot hyperspectral imaging with a lensless camera

Abstract

We present a lensless snapshot hyperspectral camera that is capable of hyperspectral imaging over a broad spectrum using a compact and low-cost hardware configuration. We leverage the multiplexing capability of a lensless camera, a novel type of computational imaging device that replaces the lens with a thin mask. Our device utilizes a linear variable filter and a phase mask to encode spectral information onto a monochromatic image sensor, enabling recovery of hyperspectral image stacks from a single measurement by utilizing spectral information encoded in different parts of the 2D point spread function. We perform spectral calibration using a reference color chart and verify the prototype device’s spectral and spatial resolution, as well as its imaging field of view. We report on the design and construction of the device, the image reconstruction algorithm, and spectral calibration methods and present hyperspectral images ranging from 410 to 800 nm obtained with our prototype device.