Recovering spectral data from natural scenes with an RGB digital camera and colored filters |
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Authors: | Eva M. Valero Juan L. Nieves Sérgio M. C. Nascimento Kinjiro Amano David H. Foster |
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Affiliation: | 1. Departamento de óptica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain;2. Department of Physics, Minho University, Campus de Gualtar, 4710‐057 Braga, Portugal;3. Sensing, Imaging, and Signal Processing Group, School of Electrical and Electronic Engineering, University of Manchester, Manchester M60 1QD, United Kingdom |
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Abstract: | Many spectral‐recovery methods using RGB digital cameras assume the underlying smoothness of illuminant and reflectance spectra, and apply low‐dimensional linear models. The aim of the present work was to test whether a direct‐mapping method could be used instead of a linear‐models approach to recover spectral radiances and reflectances from natural scenes with an RGB digital camera and colored filters. In computer simulations, a conventional RGB digital camera with up to three colored filters was used to image scenes drawn from a hyperspectral image database. Three measures were used to evaluate recovery with the direct‐mapping method: goodness‐of‐fit, root‐mean‐square error, and a color‐difference metric. It was found that with two and three filters both spectral radiances and reflectances could be recovered sufficiently accurately for many practical applications. With little increase in computational complexity, an RGB camera and a few colored filters can provide significantly better recovery of natural scenes than an RGB camera alone. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 352–360, 2007 |
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Keywords: | reflectance multispectral imaging systems illuminants natural scenes |
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