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Author Robert Benavente; Francesc Tous; Ramon Baldrich; Maria Vanrell edit  openurl
Title Statical Modelling of a Colour Naming Space. Type Miscellaneous
Year 2002 Publication (down) Proceedings of the 1st. European Conference on Colour in Graphics Imaging and Vision: 406–411. Abbreviated Journal  
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Notes CIC Approved no  
Call Number CAT @ cat @ BTB2002 Serial 289  
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Author Robert Benavente; Maria Vanrell edit  openurl
Title Parametrizacion del Espacio de Categorias de Color Type Miscellaneous
Year 2007 Publication (down) Proceedings del VIII Congreso Nacional del Color Abbreviated Journal  
Volume Issue Pages 77–78  
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Abstract  
Address Madrid (Spain)  
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Area Expedition Conference CNC’07  
Notes CAT;CIC Approved no  
Call Number CAT @ cat @ BeV2007 Serial 905  
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Author Ramon Baldrich; Ricardo Toledo; Ernest Valveny; Maria Vanrell edit  openurl
Title Perceptual Colour Image Segmentation. Type Miscellaneous
Year 2002 Publication (down) Proceeding of the Second IASTED International Conference Visualization, Imaging and Image Proceesing VIIP 2002: 145–150. Abbreviated Journal  
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Notes DAG;CIC;ADAS Approved no  
Call Number CAT @ cat @ BTV2002 Serial 290  
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Author Maria Vanrell; Felipe Lumbreras; A. Pujol; Ramon Baldrich; Josep Llados; Juan J. Villanueva edit  openurl
Title Colour Normalisation Based on Background Information. Type Miscellaneous
Year 2001 Publication (down) Proceeding ICIP 2001, IEEE International Conference on Image Processing Abbreviated Journal ICIP 2001  
Volume Issue 1 Pages 874–877  
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Abstract  
Address Grecia.  
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Area Expedition Conference  
Notes ADAS;DAG;CIC Approved no  
Call Number ADAS @ adas @ VLP2001 Serial 167  
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Author C. Alejandro Parraga; Robert Benavente; Maria Vanrell edit  openurl
Title Towards a general model of colour categorization which considers context Type Journal Article
Year 2010 Publication (down) 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  
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ISSN ISBN Medium  
Area Expedition Conference  
Notes CIC Approved no  
Call Number CAT @ cat @ PBV2010b Serial 1326  
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Author Olivier Penacchio; C. Alejandro Parraga; Maria Vanrell edit  openurl
Title Natural Scene Statistics account for Human Cones Ratios Type Journal Article
Year 2010 Publication (down) 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.		  
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 CAT @ cat @ PPV2010 Serial 1357  
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Author Xavier Otazu; Maria Vanrell edit  openurl
Title A surround-induction function to unify assimilation and contrast in a computational model of color apearance Type Miscellaneous
Year 2005 Publication (down) Perception supplement, ECVP05 Abstracts, 34: 215 Abbreviated Journal  
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Notes CIC Approved no  
Call Number CAT @ cat @ OtV2005a Serial 568  
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Author Xavier Otazu; Maria Vanrell; C. Alejandro Parraga edit  openurl
Title Colour induction effects are modelled by a low-level multiresolution wavelet framework Type Journal
Year 2008 Publication (down) Perception 37(Suppl.): 107 Abbreviated Journal  
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Area Expedition Conference  
Notes CIC Approved no  
Call Number CAT @ cat @ OVP2008b Serial 1055  
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Author C. Alejandro Parraga; Robert Benavente; Maria Vanrell edit  openurl
Title Modeling Colour-Naming Space with Fuzzy Sets Type Journal
Year 2007 Publication (down) Perception 36:198–198, supp Abbreviated Journal  
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Series Editor Series Title Abbreviated Series Title  
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Area Expedition Conference  
Notes CIC Approved no  
Call Number CAT @ cat @ PBV2007 Serial 843  
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Author Xavier Otazu; Maria Vanrell; C. Alejandro Parraga edit  openurl
Title Mutiresolution Wavelet Framework Reproduces Induction Effects Type Journal
Year 2007 Publication (down) Perception 36:167–167, supp Abbreviated Journal  
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Notes CIC Approved no  
Call Number CAT @ cat @ OVP2007 Serial 842  
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Author Javier Vazquez; C. Alejandro Parraga; Maria Vanrell edit  openurl
Title Ordinal pairwise method for natural images comparison Type Journal Article
Year 2009 Publication (down) Perception Abbreviated Journal PER  
Volume 38 Issue Pages 180  
Keywords  
Abstract 38(Suppl.)ECVP Abstract Supplement
We developed a new psychophysical method to compare different colour appearance models when applied to natural scenes. The method was as follows: two images (processed by different algorithms) were displayed on a CRT monitor and observers were asked to select the most natural of them. The original images were gathered by means of a calibrated trichromatic digital camera and presented one on top of the other on a calibrated screen. The selection was made by pressing on a 6-button IR box, which allowed observers to consider not only the most natural but to rate their selection. The rating system allowed observers to register how much more natural was their chosen image (eg, much more, definitely more, slightly more), which gave us valuable extra information on the selection process. The results were analysed considering both the selection as a binary choice (using Thurstone's law of comparative judgement) and using Bradley-Terry method for ordinal comparison. Our results show a significant difference in the rating scales obtained. Although this method has been used in colour constancy algorithm comparisons, its uses are much wider, eg to compare algorithms of image compression, rendering, recolouring, etc.		  
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Notes CIC Approved no  
Call Number CAT @ cat @ VPV2009b Serial 1191  
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Author Robert Benavente; C. Alejandro Parraga; Maria Vanrell edit  openurl
Title Colour categories boundaries are better defined in contextual conditions Type Journal Article
Year 2009 Publication (down) Perception Abbreviated Journal PER  
Volume 38 Issue Pages 36  
Keywords  
Abstract In a previous experiment [Parraga et al, 2009 Journal of Imaging Science and Technology 53(3)] the boundaries between basic colour categories were measured by asking subjects to categorize colour samples presented in isolation (ie on a dark background) using a YES/NO paradigm. Results showed that some boundaries (eg green – blue) were very diffuse and the subjects' answers presented bimodal distributions, which were attributed to the emergence of non-basic categories in those regions (eg turquoise). To confirm these results we performed a new experiment focussed on the boundaries where bimodal distributions were more evident. In this new experiment rectangular colour samples were presented surrounded by random colour patches to simulate contextual conditions on a calibrated CRT monitor. The names of two neighbouring colours were shown at the bottom of the screen and subjects selected the boundary between these colours by controlling the chromaticity of the central patch, sliding it across these categories' frontier. Results show that in this new experimental paradigm, the formerly uncertain inter-colour category boundaries are better defined and the dispersions (ie the bimodal distributions) that occurred in the previous experiment disappear. These results may provide further support to Berlin and Kay's basic colour terms theory.  
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Notes CIC Approved no  
Call Number CAT @ cat @ BPV2009 Serial 1192  
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Author C. Alejandro Parraga; Javier Vazquez; Maria Vanrell edit  openurl
Title A new cone activation-based natural images dataset Type Journal Article
Year 2009 Publication (down) 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 CAT @ cat @ PVV2009 Serial 1193  
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Author C. Alejandro Parraga; Olivier Penacchio; Maria Vanrell edit  openurl
Title Retinal Filtering Matches Natural Image Statistics at Low Luminance Levels Type Journal Article
Year 2011 Publication (down) Perception Abbreviated Journal PER  
Volume 40 Issue Pages 96  
Keywords  
Abstract The assumption that the retina’s main objective is to provide a minimum entropy representation to higher visual areas (ie efficient coding principle) allows to predict retinal filtering in space–time and colour (Atick, 1992 Network 3 213–251). This is achieved by considering the power spectra of natural images (which is proportional to 1/f2) and the suppression of retinal and image noise. However, most studies consider images within a limited range of lighting conditions (eg near noon) whereas the visual system’s spatial filtering depends on light intensity and the spatiochromatic properties of natural scenes depend of the time of the day. Here, we explore whether the dependence of visual spatial filtering on luminance match the changes in power spectrum of natural scenes at different times of the day. Using human cone-activation based naturalistic stimuli (from the Barcelona Calibrated Images Database), we show that for a range of luminance levels, the shape of the retinal CSF reflects the slope of the power spectrum at low spatial frequencies. Accordingly, the retina implements the filtering which best decorrelates the input signal at every luminance level. This result is in line with the body of work that places efficient coding as a guiding neural principle.  
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Area Expedition Conference  
Notes CIC Approved no  
Call Number Admin @ si @ PPV2011 Serial 1720  
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