Spectral Characterization of a Prototype SFA Camera for Joint Visible and NIR Acquisition

Abstract

Multispectral acquisition improves machine vision since it permits capturing more information on object surface properties than color imaging. The concept of spectral filter arrays has been developed recently and allows multispectral single shot acquisition with a compact camera design. Due to filter manufacturing difficulties, there was, up to recently, no system available for a large span of spectrum, i.e., visible and Near Infra-Red acquisition. This article presents the achievement of a prototype of camera that captures seven visible and one near infra-red bands on the same sensor chip. A calibration is proposed to characterize the sensor, and images are captured. Data are provided as supplementary material for further analysis and simulations. This opens a new range of applications in security, robotics, automotive and medical fields.

Energy balance in Spectral Filter Array camera design

“…f Zooming on an achromatic patch of the raw image to observe energy balance disparity among all channels and on the illumination. This is illustrated by Thomas et al [7], where the sensitivities of the less-sensitive band and the most-sensitive band (see Fig. 1) show a relative efficiency ratio in the interval [11%, 99%] for a set of practical filters, an ideal viewing illuminant and a perfect diffuser.…”

“…1 a Example of a mozaic element in an SFA imaging system composed of 8 channels. b Corresponding relative spectral characteristics of the camera in the work by Lapray et al [3,7] (c). Filters transmittance manufactured by SILIOS Technologies [37].…”

“…Each spatial position of the array captures only one spectral channel similarly to the Bayer filters [4], and the filter transmission characteristics determine the sensor spectral properties. Several realizations of such setup have been shown recently in the literature [5][6][7]. An *Correspondence: pierre-jean.lapray@uha.fr Université de Bourgogne Franche Comté, LE2I, UMR CNRS 6306, 9 av.…”

N-LMMSE Demosaicing for Spectral Filter Arrays

“…stanford.edu/index.php/hyperspectral-image-data/) radiance image database, 69 following the model described above. We simulate acquisition by a real sensor( Figure 6) that spans visible and NIR, 10,70 where spatial layout follows Miao binary tree. 36,71,72 The benchmark demosaicing, Miao binary tree, 34 is applied on the raw data for reconstruction.…”

“…1062-3701/2017/61(4)/040407/11/$25.00 Le2i at Université de Bourgogne, Franche-Comté, 10 the other comes from Ukotomi & Tanaka Laboratory at the Tokyo Institute of Technology. 11 Interest of these realizations is that each of them comes with a database freely available online for research, SFA database spanning the visible and near infra-red (NIR) 12 and TokyoTech Multispectral Image dataset (http://www.ok.sc.e.titech.ac.jp/res/MSI/MSIdata.ht ml).…”