A Do-It-Yourself Hyperspectral Imager Brought to Practice with Open-Source Python

Abstract

Commercial hyperspectral imagers (HSIs) are expensive and thus unobtainable for large audiences or research groups with low funding. In this study, we used an existing do-it-yourself push-broom HSI design for which we provide software to correct for spectral smile aberration without using an optical laboratory. The software also corrects an aberration which we call tilt. The tilt is specific for the particular imager design used, but correcting it may be beneficial for other similar devices. The tilt and spectral smile were reduced to zero in terms of used metrics. The software artifact is available as an open-source Github repository. We also present improved casing for the imager design, and, for those readers interested in building their own HSI, we provide print-ready and modifiable versions of the 3D-models required in manufacturing the imager. To our best knowledge, solving the spectral smile correction problem without an optical laboratory has not been previously reported. This study re-solved the problem with simpler and cheaper tools than those commonly utilized. We hope that this study will promote easier access to hyperspectral imaging for all audiences regardless of their financial status and availability of an optical laboratory.

On the Optimization of Regression-Based Spectral Reconstruction

“…Using a hyperspectral camera [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ], we can record scene radiance at high spectral and spatial resolution. This technique has been widely used in machine vision applications such as remote sensing [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ], medical imaging [ 28 , 29 , 30 , 31 ], food processing [ 32 , 33 , 34 , 35 , 36 , 37 ], and anomaly detection [ 38 , 39 , 40 , 41 , 42 , 43 , 44 ], as well as in the spectral characterization domain, including the calibration of color devices (e.g., cameras [ 45 ] and scanners [ 46 ]), scene relighting [ 47 , 48 ], and art conservation and archiving [ 49 , 50 , 51 ].…”

Compact and ultracompact spectral imagers: technology and applications in biomedical imaging

“…Riihiaho et al. 218 performed smile correction by calculating the matrix that transforms curved spectral lines into the straight lines for each spectrum. Henriksen et al.…”

“…As an example of the open-source model, Riihiaho et al. 218 built a 3D-printed spectral imaging camera with designs from Sigernes et al. 85 Some further modifications were made to reduce smile and aberration, which were publicly shared along with 3D CAD files.…”

“…Open-source design refers to the creation of software and hardware with the intention of freely sharing those designs for others to use, study, modify, and even commercialize without concerns of copyright or patent infringement. This allowance is performed through many 218 built a 3D-printed spectral imaging camera with designs from Sigernes et al 85 Some further modifications were made to reduce smile and aberration, which were publicly shared along with 3D CAD files. They also built software that performed aberration correction and shared it publicly.…”

Laboratory Hyperspectral Image Acquisition System Setup and Validation

“…The presented work also introduces a validation procedure for both the camera device and the acquired images. Aberrations such as keystone and smile are very common in pushbroom cameras [ 16 ], and usually corrected in a postprocessing phase either within the sensor electronics or afterwards [ 17 ]. For instance, the Specim devices used in this work correct these aberrations within the sensor hardware.…”