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Author | Javier Vazquez; C. Alejandro Parraga; Maria Vanrell | ||||
Title | Ordinal pairwise method for natural images comparison | Type | Journal Article | ||
Year | 2009 | Publication | Perception | Abbreviated Journal | PER |
Volume | 38 | Issue | Pages | 180 | |
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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 | ||||
Title | Colour categories boundaries are better defined in contextual conditions | Type | Journal Article | ||
Year | 2009 | Publication | Perception | Abbreviated Journal | PER |
Volume | 38 | Issue | Pages | 36 | |
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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 | ||||
Title | A new cone activation-based natural images dataset | Type | Journal Article | ||
Year | 2009 | Publication | Perception | Abbreviated Journal | PER |
Volume | 36 | Issue | Pages | 180 | |
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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 | Fahad Shahbaz Khan; Joost Van de Weijer; Maria Vanrell | ||||
Title | Top-Down Color Attention for Object Recognition | Type | Conference Article | ||
Year | 2009 | Publication | 12th International Conference on Computer Vision | Abbreviated Journal | |
Volume | Issue | Pages | 979 - 986 | ||
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Abstract | Generally the bag-of-words based image representation follows a bottom-up paradigm. The subsequent stages of the process: feature detection, feature description, vocabulary construction and image representation are performed independent of the intentioned object classes to be detected. In such a framework, combining multiple cues such as shape and color often provides below-expected results. This paper presents a novel method for recognizing object categories when using multiple cues by separating the shape and color cue. Color is used to guide attention by means of a top-down category-specific attention map. The color attention map is then further deployed to modulate the shape features by taking more features from regions within an image that are likely to contain an object instance. This procedure leads to a category-specific image histogram representation for each category. Furthermore, we argue that the method combines the advantages of both early and late fusion. We compare our approach with existing methods that combine color and shape cues on three data sets containing varied importance of both cues, namely, Soccer ( color predominance), Flower (color and shape parity), and PASCAL VOC Challenge 2007 (shape predominance). The experiments clearly demonstrate that in all three data sets our proposed framework significantly outperforms the state-of-the-art methods for combining color and shape information. | ||||
Address | Kyoto, Japan | ||||
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ISSN | 1550-5499 | ISBN | 978-1-4244-4420-5 | Medium | |
Area | Expedition | Conference | ICCV | ||
Notes | CIC | Approved | no | ||
Call Number | CAT @ cat @ SWV2009 | Serial | 1196 | ||
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Author | Jaime Moreno; Xavier Otazu; Maria Vanrell | ||||
Title | Local Perceptual Weighting in JPEG2000 for Color Images | 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 | 255–260 | ||
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Abstract | The aim of this work is to explain how to apply perceptual concepts to define a perceptual pre-quantizer and to improve JPEG2000 compressor. The approach consists in quantizing wavelet transform coefficients using some of the human visual system behavior properties. Noise is fatal to image compression performance, because it can be both annoying for the observer and consumes excessive bandwidth when the imagery is transmitted. Perceptual pre-quantization reduces unperceivable details and thus improve both visual impression and transmission properties. The comparison between JPEG2000 without and with perceptual pre-quantization shows that the latter is not favorable in PSNR, but the recovered image is more compressed at the same or even better visual quality measured with a weighted PSNR. Perceptual criteria were taken from the CIWaM (Chromatic Induction Wavelet Model). | ||||
Address | Joensuu, Finland | ||||
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ISSN | ISBN | 9781617388897 | Medium | ||
Area | Expedition | Conference | CGIV/MCS | ||
Notes | CIC | Approved | no | ||
Call Number | CAT @ cat @ MOV2010a | Serial | 1307 | ||
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Author | Jaime Moreno; Xavier Otazu; Maria Vanrell | ||||
Title | Contribution of CIWaM in JPEG2000 Quantization for Color Images | Type | Conference Article | ||
Year | 2010 | Publication | Proceedings of The CREATE 2010 Conference | Abbreviated Journal | |
Volume | Issue | Pages | 132–136 | ||
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Abstract | The aim of this work is to explain how to apply perceptual concepts to define a perceptual pre-quantizer and to improve JPEG2000 compressor. The approach consists in quantizing wavelet transform coefficients using some of the human visual system behavior properties. Noise is fatal to image compression performance, because it can be both annoying for the observer and consumes excessive bandwidth when the imagery is transmitted. Perceptual pre-quantization reduces unperceivable details and thus improve both visual impression and transmission properties. The comparison between JPEG2000 without and with perceptual pre-quantization shows that the latter is not favorable in PSNR, but the recovered image is more compressed at the same or even better visual quality measured with a weighted PSNR. Perceptual criteria were taken from the CIWaM(ChromaticInductionWaveletModel). | ||||
Address | Gjovik (Norway) | ||||
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Area | Expedition | Conference | CREATE | ||
Notes | CIC | Approved | no | ||
Call Number | CAT @ cat @ MOV2010b | Serial | 1308 | ||
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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 | ||
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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 | ||||
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Language | Summary Language | Original Title | |||
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ISSN | ISBN | 9781617388897 | Medium | ||
Area | Expedition | Conference | CGIV/MCS | ||
Notes | CIC | Approved | no | ||
Call Number | CAT @ cat @ PBV2010a | Serial | 1322 | ||
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Author | Javier Vazquez; G. D. Finlayson; Maria Vanrell | ||||
Title | A compact singularity function to predict WCS data and unique hues | 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 | 33–38 | ||
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Abstract | Understanding how colour is used by the human vision system is a widely studied research field. The field, though quite advanced, still faces important unanswered questions. One of them is the explanation of the unique hues and the assignment of color names. This problem addresses the fact of different perceptual status for different colors.
Recently, Philipona and O'Regan have proposed a biological model that allows to extract the reflection properties of any surface independently of the lighting conditions. These invariant properties are the basis to compute a singularity index that predicts the asymmetries presented in unique hues and basic color categories psychophysical data, therefore is giving a further step in their explanation. In this paper we build on their formulation and propose a new singularity index. This new formulation equally accounts for the location of the 4 peaks of the World colour survey and has two main advantages. First, it is a simple elegant numerical measure (the Philipona measurement is a rather cumbersome formula). Second, we develop a colour-based explanation for the measure. |
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Address | Joensuu, Finland | ||||
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Language | Summary Language | Original Title | |||
Series Editor | Series Title | Abbreviated Series Title ![]() |
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Series Volume | Series Issue | Edition | |||
ISSN | ISBN | 9781617388897 | Medium | ||
Area | Expedition | Conference | CGIV/MCS | ||
Notes | CIC | Approved | no | ||
Call Number | CAT @ cat @ VFV2010 | Serial | 1324 | ||
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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 | |
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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 dierences but it was not possible to conclude whether this discrepancy was due to the absence/presence of a colourful background or to the dierences 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 dierent(more diuse) 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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Area | Expedition | Conference | |||
Notes | CIC | Approved | no | ||
Call Number | CAT @ cat @ PBV2010b | Serial | 1326 | ||
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Author | Robert Benavente; C. Alejandro Parraga; Maria Vanrell | ||||
Title | La influencia del contexto en la definicion de las fronteras entre las categorias cromaticas | Type | Conference Article | ||
Year | 2010 | Publication | 9th Congreso Nacional del Color | Abbreviated Journal | |
Volume | Issue | Pages | 92–95 | ||
Keywords | Categorización del color; Apariencia del color; Influencia del contexto; Patrones de Mondrian; Modelos paramétricos | ||||
Abstract | En este artículo presentamos los resultados de un experimento de categorización de color en el que las muestras se presentaron sobre un fondo multicolor (Mondrian) para simular los efectos del contexto. Los resultados se comparan con los de un experimento previo que, utilizando un paradigma diferente, determinó las fronteras sin tener en cuenta el contexto. El análisis de los resultados muestra que las fronteras obtenidas con el experimento en contexto presentan menos confusión que las obtenidas en el experimento sin contexto. | ||||
Address | Alicante (Spain) | ||||
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ISSN | ISBN | 978-84-9717-144-1 | Medium | ||
Area | Expedition | Conference | CNC | ||
Notes | CIC | Approved | no | ||
Call Number | CAT @ cat @ BPV2010 | Serial | 1327 | ||
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Author | Javier Vazquez; Maria Vanrell; Robert Benavente | ||||
Title | Color names as a constraint for Computer Vision problems | Type | Conference Article | ||
Year | 2010 | Publication | Proceedings of The CREATE 2010 Conference | Abbreviated Journal | |
Volume | Issue | Pages | 324–328 | ||
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Abstract | Computer Vision Problems are usually ill-posed. Constraining de gamut of possible solutions is then a necessary step. Many constrains for different problems have been developed during years. In this paper, we present a different way of constraining some of these problems: the use of color names. In particular, we will focus on segmentation, representation ans constancy. | ||||
Address | Gjovik (Norway) | ||||
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Area | Expedition | Conference | CREATE | ||
Notes | CIC | Approved | no | ||
Call Number | CAT @ cat @ VVB2010 | Serial | 1328 | ||
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Author | Fahad Shahbaz Khan; Joost Van de Weijer; Maria Vanrell | ||||
Title | Who Painted this Painting? | Type | Conference Article | ||
Year | 2010 | Publication | Proceedings of The CREATE 2010 Conference | Abbreviated Journal | |
Volume | Issue | Pages | 329–333 | ||
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Address | Gjovik (Norway) | ||||
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Area | Expedition | Conference | CREATE | ||
Notes | CIC | Approved | no | ||
Call Number | CAT @ cat @ KWV2010 | Serial | 1329 | ||
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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 | |
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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 dierences but it was not possible to conclude whether this discrepancy was due to the absence/presence of a colourful background or to the dierences 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 dierent(more diuse) 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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Area | Expedition | Conference | |||
Notes | CIC | Approved | no | ||
Call Number | CAT @ cat @ PPV2010 | Serial | 1357 | ||
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Author | Susana Alvarez; Anna Salvatella; Maria Vanrell; Xavier Otazu | ||||
Title | Perceptual color texture codebooks for retrieving in highly diverse texture datasets | Type | Conference Article | ||
Year | 2010 | Publication | 20th International Conference on Pattern Recognition | Abbreviated Journal | |
Volume | Issue | Pages | 866–869 | ||
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Abstract | Color and texture are visual cues of different nature, their integration in a useful visual descriptor is not an obvious step. One way to combine both features is to compute texture descriptors independently on each color channel. A second way is integrate the features at a descriptor level, in this case arises the problem of normalizing both cues. A significant progress in the last years in object recognition has provided the bag-of-words framework that again deals with the problem of feature combination through the definition of vocabularies of visual words. Inspired in this framework, here we present perceptual textons that will allow to fuse color and texture at the level of p-blobs, which is our feature detection step. Feature representation is based on two uniform spaces representing the attributes of the p-blobs. The low-dimensionality of these text on spaces will allow to bypass the usual problems of previous approaches. Firstly, no need for normalization between cues; and secondly, vocabularies are directly obtained from the perceptual properties of text on spaces without any learning step. Our proposal improve current state-of-art of color-texture descriptors in an image retrieval experiment over a highly diverse texture dataset from Corel. | ||||
Address | Istanbul (Turkey) | ||||
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Series Volume | Series Issue | Edition | |||
ISSN | 1051-4651 | ISBN | 978-1-4244-7542-1 | Medium | |
Area | Expedition | Conference | ICPR | ||
Notes | CIC | Approved | no | ||
Call Number | CAT @ cat @ ASV2010b | Serial | 1426 | ||
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