Comparative performance analysis of spectral estimation algorithms and computational optimization of a multispectral imaging system for print inspection |
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| Authors: | Eva M Valero Yu Hu Javier Hernández‐Andrés Timo Eckhard Juan L Nieves Javier Romero Markus Schnitzlein Dietmar Nowack |
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| Affiliation: | 1. Department of Optics, Faculty of Sciences, University of Granada, s/n 18071 Granada, Spain;2. Chromasens GmbH, 78467 Konstanz, Germany |
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| Abstract: | We have analyzed the performance of simulated multispectral systems for the spectral recovery of reflectance of printer inks from camera responses, including noise. To estimate reflectance we compared the performance of four algorithms which were not comparatively tested using the same data sets before. The criteria for selection of the algorithms were robustness against noise, amount of data needed as inputs (training set, spectral responsivities) and lacking of use of dimensionality reduction techniques. Three different sensor sets and training sets were used. We analyzed the differences in the spanning of the subspaces found for the three training sets, concluding that the ink reflectances have characteristic features. The best performance was obtained using the kernel and the radial basis function neural‐net‐based algorithms for the training set composed of printer inks reflectances, whereas for the other two training sets (composed of samples from the ColorChecker DC and Vhrel's reflectances' set) the quality of the recovered samples was more uniform among the algorithms. We also have performed an optimization to choose the best sensor set for the multispectral system with a reduced number of sensors. © 2012 Wiley Periodicals, Inc. Col Res Appl, 39, 16–27, 2014 |
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| Keywords: | multispectral imaging spectral estimation |
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