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Author C. Alejandro Parraga; Javier Vazquez; Maria Vanrell
Title A new cone activation-based natural images dataset Type Journal Article
Year 2009 Publication Perception Abbreviated Journal PER
Volume 36 Issue Pages 180
Keywords
Abstract We generated a new dataset of digital natural images where each colour plane corresponds to the human LMS (long-, medium-, short-wavelength) cone activations. The images were chosen to represent five different visual environments (eg forest, seaside, mountain snow, urban, motorways) and were taken under natural illumination at different times of day. At the bottom-left corner of each picture there was a matte grey ball of approximately constant spectral reflectance (across the camera's response spectrum,) and nearly Lambertian reflective properties, which allows to compute (and remove, if necessary) the illuminant's colour and intensity. The camera (Sigma Foveon SD10) was calibrated by measuring its sensor's spectral responses using a set of 31 spectrally narrowband interference filters. This allowed conversion of the final camera-dependent RGB colour space into the Smith and Pokorny (1975) cone activation space by means of a polynomial transformation, optimised for a set of 1269 Munsell chip reflectances. This new method is an improvement over the usual 3 × 3 matrix transformation which is only accurate for spectrally-narrowband colours. The camera-to-LMS transformation can be recalculated to consider other non-human visual systems. The dataset is available to download from our website.
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Notes CIC Approved no
Call Number (down) CAT @ cat @ PVV2009 Serial 1193
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Author Olivier Penacchio; C. Alejandro Parraga; Maria Vanrell
Title Natural Scene Statistics account for Human Cones Ratios Type Journal Article
Year 2010 Publication Perception. ECVP Abstract Supplement Abbreviated Journal PER
Volume 39 Issue Pages 101
Keywords
Abstract In two previous experiments [Parraga et al, 2009 J. of Im. Sci. and Tech 53(3) 031106; Benavente et al,2009 Perception 38 ECVP Supplement, 36] the boundaries of basic colour categories were measured.
In the first experiment, samples were presented in isolation (ie on a dark background) and boundaries were measured using a yes/no paradigm. In the second, subjects adjusted the chromaticity of a sample presented on a random Mondrian background to find the boundary between pairs of adjacent colours.
Results from these experiments showed significant di erences but it was not possible to conclude whether this discrepancy was due to the absence/presence of a colourful background or to the di erences in the paradigms used. In this work, we settle this question by repeating the first experiment (ie samples presented on a dark background) using the second paradigm. A comparison of results shows that
although boundary locations are very similar, boundaries measured in context are significantly di erent(more di use) than those measured in isolation (confirmed by a Student’s t-test analysis on the subject’s answers statistical distributions). In addition, we completed the mapping of colour name space by measuring the boundaries between chromatic colours and the achromatic centre. With these results we completed our parametric fuzzy-sets model of colour naming space.
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Notes CIC Approved no
Call Number (down) CAT @ cat @ PPV2010 Serial 1357
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Author C. Alejandro Parraga; Robert Benavente; Maria Vanrell
Title Towards a general model of colour categorization which considers context Type Journal Article
Year 2010 Publication Perception. ECVP Abstract Supplement Abbreviated Journal PER
Volume 39 Issue Pages 86
Keywords
Abstract In two previous experiments [Parraga et al, 2009 J. of Im. Sci. and Tech 53(3) 031106; Benavente et al,2009 Perception 38 ECVP Supplement, 36] the boundaries of basic colour categories were measured.
In the first experiment, samples were presented in isolation (ie on a dark background) and boundaries were measured using a yes/no paradigm. In the second, subjects adjusted the chromaticity of a sample presented on a random Mondrian background to find the boundary between pairs of adjacent colours.
Results from these experiments showed significant di erences but it was not possible to conclude whether this discrepancy was due to the absence/presence of a colourful background or to the di erences in the paradigms used. In this work, we settle this question by repeating the first experiment (ie samples presented on a dark background) using the second paradigm. A comparison of results shows that
although boundary locations are very similar, boundaries measured in context are significantly di erent(more di use) than those measured in isolation (confirmed by a Student’s t-test analysis on the subject’s answers statistical distributions). In addition, we completed the mapping of colour name space by measuring the boundaries between chromatic colours and the achromatic centre. With these results we
completed our parametric fuzzy-sets model of colour naming space.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes CIC Approved no
Call Number (down) CAT @ cat @ PBV2010b Serial 1326
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Author C. Alejandro Parraga; Ramon Baldrich; Maria Vanrell
Title Accurate Mapping of Natural Scenes Radiance to Cone Activation Space: A New Image Dataset Type Conference Article
Year 2010 Publication 5th European Conference on Colour in Graphics, Imaging and Vision and 12th International Symposium on Multispectral Colour Science Abbreviated Journal
Volume Issue Pages 50–57
Keywords
Abstract The characterization of trichromatic cameras is usually done in terms of a device-independent color space, such as the CIE 1931 XYZ space. This is indeed convenient since it allows the testing of results against colorimetric measures. We have characterized our camera to represent human cone activation by mapping the camera sensor's (RGB) responses to human (LMS) through a polynomial transformation, which can be “customized” according to the types of scenes we want to represent. Here we present a method to test the accuracy of the camera measures and a study on how the choice of training reflectances for the polynomial may alter the results.
Address Joensuu, Finland
Corporate Author Thesis
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ISSN ISBN 9781617388897 Medium
Area Expedition Conference CGIV/MCS
Notes CIC Approved no
Call Number (down) CAT @ cat @ PBV2010a Serial 1322
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Author C. Alejandro Parraga; Robert Benavente; Maria Vanrell; Ramon Baldrich
Title Psychophysical measurements to model inter-colour regions of colour-naming space Type Journal Article
Year 2009 Publication Journal of Imaging Science and Technology Abbreviated Journal
Volume 53 Issue 3 Pages 031106 (8 pages)
Keywords image processing; Analysis
Abstract JCR Impact Factor 2009: 0.391
In this paper, we present a fuzzy-set of parametric functions which segment the CIE lab space into eleven regions which correspond to the group of common universal categories present in all evolved languages as identified by anthropologists and linguists. The set of functions is intended to model a color-name assignment task by humans and differs from other models in its emphasis on the inter-color boundary regions, which were explicitly measured by means of a psychophysics experiment. In our particular implementation, the CIE lab space was segmented into eleven color categories using a Triple Sigmoid as the fuzzy sets basis, whose parameters are included in this paper. The model’s parameters were adjusted according to the psychophysical results of a yes/no discrimination paradigm where observers had to choose (English) names for isoluminant colors belonging to regions in-between neighboring categories. These colors were presented on a calibrated CRT monitor (14-bit x 3 precision). The experimental results show that inter- color boundary regions are much less defined than expected and color samples other than those near the most representatives are needed to define the position and shape of boundaries between categories. The extended set of model parameters is given as a table.
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Notes CIC Approved no
Call Number (down) CAT @ cat @ PBV2009 Serial 1157
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Author C. Alejandro Parraga; Robert Benavente; Maria Vanrell; Ramon Baldrich
Title Modelling Inter-Colour Regions of Colour Naming Space Type Conference Article
Year 2008 Publication 4th European Conference on Colour in Graphics, Imaging and Vision Proceedings Abbreviated Journal
Volume Issue Pages 218–222
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Abstract
Address Terrassa (Spain)
Corporate Author Thesis
Publisher Place of Publication Editor
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference CGIV08
Notes CAT;CIC Approved no
Call Number (down) CAT @ cat @ PBV2008 Serial 969
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Author C. Alejandro Parraga; Robert Benavente; Maria Vanrell
Title Modeling Colour-Naming Space with Fuzzy Sets Type Journal
Year 2007 Publication Perception 36:198–198, supp Abbreviated Journal
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Notes CIC Approved no
Call Number (down) CAT @ cat @ PBV2007 Serial 843
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Author Xavier Otazu; Maria Vanrell; C. Alejandro Parraga
Title Colour induction effects are modelled by a low-level multiresolution wavelet framework Type Journal
Year 2008 Publication Perception 37(Suppl.): 107 Abbreviated Journal
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Notes CIC Approved no
Call Number (down) CAT @ cat @ OVP2008b Serial 1055
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Author Xavier Otazu; Maria Vanrell; C. Alejandro Parraga
Title Multiresolution Wavelet Framework Models Brightness Induction Effects Type Journal
Year 2008 Publication Vision Research Abbreviated Journal VR
Volume 48 Issue 5 Pages 733–751
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Notes CIC Approved no
Call Number (down) CAT @ cat @ OVP2008a Serial 927
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Author Xavier Otazu; Maria Vanrell; C. Alejandro Parraga
Title Mutiresolution Wavelet Framework Reproduces Induction Effects Type Journal
Year 2007 Publication Perception 36:167–167, supp Abbreviated Journal
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Notes CIC Approved no
Call Number (down) CAT @ cat @ OVP2007 Serial 842
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Author Xavier Otazu; Maria Vanrell
Title Several lightness induction effects with a computational multiresolution wavelet framework Type Journal
Year 2006 Publication 29th European Conference on Visual Perception (ECVP’06), Perception Suppl s, 32: 56–56 Abbreviated Journal
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Address Saint-Petersburg (Russia)
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Notes CIC Approved no
Call Number (down) CAT @ cat @ OtV2006 Serial 659
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Author Xavier Otazu; Maria Vanrell
Title Perceptual representation of textured images Type Journal
Year 2005 Publication Journal of Imaging Science and Technology, 49(3):262–271 (IF: 0.522) Abbreviated Journal
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Notes CIC Approved no
Call Number (down) CAT @ cat @ OtV2005b Serial 542
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Author Xavier Otazu; Maria Vanrell
Title A surround-induction function to unify assimilation and contrast in a computational model of color apearance Type Miscellaneous
Year 2005 Publication Perception supplement, ECVP05 Abstracts, 34: 215 Abbreviated Journal
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Notes CIC Approved no
Call Number (down) CAT @ cat @ OtV2005a Serial 568
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Author Xavier Otazu; Maria Vanrell
Title Building Perceived Colour Images. Type Miscellaneous
Year 2004 Publication CGIV 2004 Second European Conference on Colour in Graphics, Imaging, and Vision, 140:145 Abbreviated Journal
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Address Aachen (Germany)
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Notes CIC Approved no
Call Number (down) CAT @ cat @ OtV2004 Serial 450
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Author Xavier Otazu; M. Ribo; J.M. Paredes; M. Peracaula; J. Nuñez
Title Multiresolution approach for period determination on unevenly sampled data Type Journal
Year 2004 Publication Monthly Notices of the Royal Astronomical Society, 351:251–219 (IF: 5.238) Abbreviated Journal
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Notes CIC Approved no
Call Number (down) CAT @ cat @ ORP2004 Serial 451
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