Abstract

The centroid wavelength of liquid crystal tunable filters (LCTFs), by definition, changes with incident angle, resulting in an imaging system with spectral sensitivity that varies across the image plane. Prior to this research, this effect was considered negligible. Imaging uniform colored papers with high chroma revealed that the effect is appreciable. A regression-based method of modeling and correcting systematic spectrophotometric errors in conventional reflectance spectrophotometry was used to correct this wavelength-dependent spatial nonuniformity in an LCTF imaging system. For six high chroma sheets of spatially uniform paper, the uniformity was reduced from an average and maximum of 0.95 and 4.00, respectively, to 0.08 and 0.18 CIEDE2000. The same method was used to transfer the scale of spectral reflectance factor from a reference spectrophotometer to the imaging system such that its reported values matched the reference spectrophotometer with a constant bandwidth. For an independent color target, residual errors were 0.008 spectral reflectance factor RMS difference and 0.44 and 1.65 average and maximum CIEDE2000, respectively (0.63 and 2.34 $\mathrm{\Delta }{E}_{ab}^{*}$).

© 2015 Optical Society of America

Compressive spectral imaging system based on liquid crystal tunable filter

Xi Wang, Yuhan Zhang, Xu Ma, Tingfa Xu, and Gonzalo R. Arce
Opt. Express 26(19) 25226-25243 (2018)

Liquid-crystal tunable filter spectral imaging for brain tumor demarcation

Steven C. Gebhart, Reid C. Thompson, and Anita Mahadevan-Jansen
Appl. Opt. 46(10) 1896-1910 (2007)

Developing an optimum computer-designed multispectral system comprising a monochrome CCD camera and a liquid-crystal tunable filter

Miguel A. López-Álvarez, Javier Hernández-Andrés, and Javier Romero
Appl. Opt. 47(24) 4381-4390 (2008)

Empirical model for matching spectrophotometric reflectance of yarn windings and multispectral imaging reflectance of single strands of yarns

Lin Luo, Hui-Liang Shen, Si-Jie Shao, and John Xin
J. Opt. Soc. Am. A 32(8) 1459-1467 (2015)

Radiometric calibration and noise estimation of acousto-optic tunable filter hyperspectral imaging systems

Jaka Katrašnik, Franjo Pernuš, and Boštjan Likar
Appl. Opt. 52(15) 3526-3537 (2013)