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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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CAT @ cat @ VPV2009b | Serial | 1191 | ||
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Author | Eduard Vazquez; Francesc Tous; Ramon Baldrich; Maria Vanrell | ||||
Title | n-Dimensional Distribution Reduction Preserving its Structure | Type | Book Chapter | ||
Year | 2006 | Publication | Artificial Intelligence Research and Development, M. Polit et al. (Eds.), 146: 167–175 | Abbreviated Journal | |
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Address | IOS Press | ||||
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Notes | CIC | Approved | no | ||
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CAT @ cat @ VTB2006a | Serial | 681 | ||
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Author | Javier Vazquez; Maria Vanrell; Ramon Baldrich | ||||
Title | Towards a Psychophysical Evaluation of Colour Constancy Algorithms | Type | Conference Article | ||
Year | 2008 | Publication | 4th European Conference on Colour in Graphics, Imaging and Vision Proceedings | Abbreviated Journal | |
Volume | Issue | Pages | 372–377 | ||
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Address | Terrassa (Spain) | ||||
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Area | Expedition | Conference | CGIV08 | ||
Notes | CAT;CIC | Approved | no | ||
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CAT @ cat @ VVB2008a | Serial | 968 | ||
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Author | Eduard Vazquez; Joost Van de Weijer; Ramon Baldrich | ||||
Title | Image Segmentation in the Presence of Shadows and Highligts | Type | Conference Article | ||
Year | 2008 | Publication | 10th European Conference on Computer Vision | Abbreviated Journal | |
Volume | 5305 | Issue | Pages | 1–14 | |
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Address | Marseille (France) | ||||
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Series Editor | Series Title | Abbreviated Series Title | LNCS | ||
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Area | Expedition | Conference | ECCV | ||
Notes | CAT;CIC | Approved | no | ||
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CAT @ cat @ VVB2008b | Serial | 1013 | ||
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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 | ||
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CAT @ cat @ VVB2010 | Serial | 1328 | ||
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Author | Javier Vazquez; Maria Vanrell; Anna Salvatella; Eduard Vazquez | ||||
Title | A colour space based on the image content | Type | Book Chapter | ||
Year | 2007 | Publication | Artificial Intelligence Research and Development, C. Angulo and L. Godo, pp 205–212 IOS Press | Abbreviated Journal | |
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Notes | CIC | Approved | no | ||
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CAT @ cat @ VVS2007 | Serial | 829 | ||
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Author | Joost Van de Weijer; Theo Gevers; A. Gijsenij | ||||
Title | Edge-Based Color Constancy | Type | Journal | ||
Year | 2007 | Publication | IEEE Trans. on Image Processing, vol. 16(9):2207–2214 | Abbreviated Journal | |
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Notes | ISE | Approved | no | ||
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CAT @ cat @ WGG2007 | Serial | 949 | ||
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Author | T. Widemann; Xavier Otazu | ||||
Title | Titanias radius and an upper limit on its atmosphere from the September 8, 2001 stellar occultation | Type | Journal Article | ||
Year | 2009 | Publication | International Journal of Solar System Studies | Abbreviated Journal | |
Volume | 199 | Issue | 2 | Pages | 458–476 |
Keywords | Occultations; Uranus, satellites; Satellites, shapes; Satellites, dynamics; Ices; Satellites, atmospheres | ||||
Abstract | On September 8, 2001 around 2 h UT, the largest uranian moon, Titania, occulted Hipparcos star 106829 (alias SAO 164538, a V=7.2, K0 III star). This was the first-ever observed occultation by this satellite, a rare event as Titania subtends only 0.11 arcsec on the sky. The star's unusual brightness allowed many observers, both amateurs or professionals, to monitor this unique event, providing fifty-seven occultations chords over three continents, all reported here. Selecting the best 27 occultation chords, and assuming a circular limb, we derive Titania's radius: View the MathML source (1-σ error bar). This implies a density of View the MathML source using the value View the MathML source derived by Taylor [Taylor, D.B., 1998. Astron. Astrophys. 330, 362–374]. We do not detect any significant difference between equatorial and polar radii, in the limit View the MathML source, in agreement with Voyager limb image retrieval during the 1986 flyby. Titania's offset with respect to the DE405 + URA027 (based on GUST86 theory) ephemeris is derived: ΔαTcos(δT)=−108±13 mas and ΔδT=−62±7 mas (ICRF J2000.0 system). Most of this offset is attributable to a Uranus' barycentric offset with respect to DE405, that we estimate to be: View the MathML source and ΔδU=−85±25 mas at the moment of occultation. This offset is confirmed by another Titania stellar occultation observed on August 1st, 2003, which provides an offset of ΔαTcos(δT)=−127±20 mas and ΔδT=−97±13 mas for the satellite. The combined ingress and egress data do not show any significant hint for atmospheric refraction, allowing us to set surface pressure limits at the level of 10–20 nbar. More specifically, we find an upper limit of 13 nbar (1-σ level) at 70 K and 17 nbar at 80 K, for a putative isothermal CO2 atmosphere. We also provide an upper limit of 8 nbar for a possible CH4 atmosphere, and 22 nbar for pure N2, again at the 1-σ level. We finally constrain the stellar size using the time-resolved star disappearance and reappearance at ingress and egress. We find an angular diameter of 0.54±0.03 mas (corresponding to View the MathML source projected at Titania). With a distance of 170±25 parsecs, this corresponds to a radius of 9.8±0.2 solar radii for HIP 106829, typical of a K0 III giant. | ||||
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Publisher | ELSEVIER | Place of Publication | Editor | ||
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Series Volume | Series Issue | Edition | |||
ISSN | 0019-1035 | ISBN | Medium | ||
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Notes | CIC | Approved | no | ||
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CAT @ cat @ Wid2009 | Serial | 1052 | ||
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Author | Joost Van de Weijer; Cordelia Schmid; Jakob Verbeek; Diane Larlus | ||||
Title | Learning Color Names for Real-World Applications | Type | Journal Article | ||
Year | 2009 | Publication | IEEE Transaction in Image Processing | Abbreviated Journal | TIP |
Volume | 18 | Issue | 7 | Pages | 1512–1524 |
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Abstract | Color names are required in real-world applications such as image retrieval and image annotation. Traditionally, they are learned from a collection of labelled color chips. These color chips are labelled with color names within a well-defined experimental setup by human test subjects. However naming colors in real-world images differs significantly from this experimental setting. In this paper, we investigate how color names learned from color chips compare to color names learned from real-world images. To avoid hand labelling real-world images with color names we use Google Image to collect a data set. Due to limitations of Google Image this data set contains a substantial quantity of wrongly labelled data. We propose several variants of the PLSA model to learn color names from this noisy data. Experimental results show that color names learned from real-world images significantly outperform color names learned from labelled color chips for both image retrieval and image annotation. | ||||
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ISSN | 1057-7149 | ISBN | Medium | ||
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Notes | Approved | no | |||
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CAT @ cat @ WSV2009 | Serial | 1195 | ||
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Author | Marc Castello; Jordi Gonzalez; Ariel Amato; Pau Baiget; Carles Fernandez; Josep M. Gonfaus; Ramon Mollineda; Marco Pedersoli; Nicolas Perez de la Blanca; Xavier Roca | ||||
Title | Exploiting Multimodal Interaction Techniques for Video-Surveillance | Type | Book Chapter | ||
Year | 2013 | Publication | Multimodal Interaction in Image and Video Applications Intelligent Systems Reference Library | Abbreviated Journal | |
Volume | 48 | Issue | 8 | Pages | 135-151 |
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Abstract | In this paper we present an example of a video surveillance application that exploits Multimodal Interactive (MI) technologies. The main objective of the so-called VID-Hum prototype was to develop a cognitive artificial system for both the detection and description of a particular set of human behaviours arising from real-world events. The main procedure of the prototype described in this chapter entails: (i) adaptation, since the system adapts itself to the most common behaviours (qualitative data) inferred from tracking (quantitative data) thus being able to recognize abnormal behaviors; (ii) feedback, since an advanced interface based on Natural Language understanding allows end-users the communicationwith the prototype by means of conceptual sentences; and (iii) multimodality, since a virtual avatar has been designed to describe what is happening in the scene, based on those textual interpretations generated by the prototype. Thus, the MI methodology has provided an adequate framework for all these cooperating processes. | ||||
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Publisher | Springer Berlin Heidelberg | Place of Publication | Editor | ||
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ISSN | 1868-4394 | ISBN | 978-3-642-35931-6 | Medium | |
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Notes | ISE; 605.203; 600.049 | Approved | no | ||
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CGA2013 | Serial | 2222 | ||
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Author | Murad Al Haj; Andrew Bagdanov; Jordi Gonzalez; Xavier Roca | ||||
Title | Robust and Efficient Multipose Face Detection Using Skin Color Segmentation | Type | Conference Article | ||
Year | 2009 | Publication | 4th Iberian Conference on Pattern Recognition and Image Analysis | Abbreviated Journal | |
Volume | 5524 | Issue | Pages | ||
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Abstract | In this paper we describe an efficient technique for detecting faces in arbitrary images and video sequences. The approach is based on segmentation of images or video frames into skin-colored blobs using a pixel-based heuristic. Scale and translation invariant features are then computed from these segmented blobs which are used to perform statistical discrimination between face and non-face classes. We train and evaluate our method on a standard, publicly available database of face images and analyze its performance over a range of statistical pattern classifiers. The generalization of our approach is illustrated by testing on an independent sequence of frames containing many faces and non-faces. These experiments indicate that our proposed approach obtains false positive rates comparable to more complex, state-of-the-art techniques, and that it generalizes better to new data. Furthermore, the use of skin blobs and invariant features requires fewer training samples since significantly fewer non-face candidate regions must be considered when compared to AdaBoost-based approaches. | ||||
Address | Springer Berlin Heidelberg | ||||
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Publisher | Springer Berlin Heidelberg | Place of Publication | Editor | ||
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Series Editor | Series Title | Abbreviated Series Title | LNCS | ||
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ISSN | 0302-9743 | ISBN | 978-3-642-02171-8 | Medium | |
Area | Expedition | Conference | IbPRIA | ||
Notes | ISE | Approved | no | ||
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DAG @ dag @ ABG2009 | Serial | 1216 | ||
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Author | Murad Al Haj; Andrew Bagdanov; Jordi Gonzalez; Xavier Roca | ||||
Title | Reactive object tracking with a single PTZ camera | Type | Conference Article | ||
Year | 2010 | Publication | 20th International Conference on Pattern Recognition | Abbreviated Journal | |
Volume | Issue | Pages | 1690–1693 | ||
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Abstract | In this paper we describe a novel approach to reactive tracking of moving targets with a pan-tilt-zoom camera. The approach uses an extended Kalman filter to jointly track the object position in the real world, its velocity in 3D and the camera intrinsics, in addition to the rate of change of these parameters. The filter outputs are used as inputs to PID controllers which continuously adjust the camera motion in order to reactively track the object at a constant image velocity while simultaneously maintaining a desirable target scale in the image plane. We provide experimental results on simulated and real tracking sequences to show how our tracker is able to accurately estimate both 3D object position and camera intrinsics with very high precision over a wide range of focal lengths. | ||||
Address | Istanbul (Turkey) | ||||
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ISSN | 1051-4651 | ISBN | 978-1-4244-7542-1 | Medium | |
Area | Expedition | Conference | ICPR | ||
Notes | ISE | Approved | no | ||
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DAG @ dag @ ABG2010 | Serial | 1418 | ||
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Author | Jon Almazan; David Fernandez; Alicia Fornes; Josep Llados; Ernest Valveny | ||||
Title | A Coarse-to-Fine Approach for Handwritten Word Spotting in Large Scale Historical Documents Collection | Type | Conference Article | ||
Year | 2012 | Publication | 13th International Conference on Frontiers in Handwriting Recognition | Abbreviated Journal | |
Volume | Issue | Pages | 453-458 | ||
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Abstract | In this paper we propose an approach for word spotting in handwritten document images. We state the problem from a focused retrieval perspective, i.e. locating instances of a query word in a large scale dataset of digitized manuscripts. We combine two approaches, namely one based on word segmentation and another one segmentation-free. The first approach uses a hashing strategy to coarsely prune word images that are unlikely to be instances of the query word. This process is fast but has a low precision due to the errors introduced in the segmentation step. The regions containing candidate words are sent to the second process based on a state of the art technique from the visual object detection field. This discriminative model represents the appearance of the query word and computes a similarity score. In this way we propose a coarse-to-fine approach achieving a compromise between efficiency and accuracy. The validation of the model is shown using a collection of old handwritten manuscripts. We appreciate a substantial improvement in terms of precision regarding the previous proposed method with a low computational cost increase. | ||||
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ISSN | ISBN | 978-1-4673-2262-1 | Medium | ||
Area | Expedition | Conference | ICFHR | ||
Notes | DAG | Approved | no | ||
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DAG @ dag @ AFF2012 | Serial | 1983 | ||
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Author | Jon Almazan; Alicia Fornes; Ernest Valveny | ||||
Title | A non-rigid appearance model for shape description and recognition | Type | Journal Article | ||
Year | 2012 | Publication | Pattern Recognition | Abbreviated Journal | PR |
Volume | 45 | Issue | 9 | Pages | 3105--3113 |
Keywords | Shape recognition; Deformable models; Shape modeling; Hand-drawn recognition | ||||
Abstract | In this paper we describe a framework to learn a model of shape variability in a set of patterns. The framework is based on the Active Appearance Model (AAM) and permits to combine shape deformations with appearance variability. We have used two modifications of the Blurred Shape Model (BSM) descriptor as basic shape and appearance features to learn the model. These modifications permit to overcome the rigidity of the original BSM, adapting it to the deformations of the shape to be represented. We have applied this framework to representation and classification of handwritten digits and symbols. We show that results of the proposed methodology outperform the original BSM approach. | ||||
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ISSN | 0031-3203 | ISBN | Medium | ||
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Notes | DAG | Approved | no | ||
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DAG @ dag @ AFV2012 | Serial | 1982 | ||
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Author | Jon Almazan; Albert Gordo; Alicia Fornes; Ernest Valveny | ||||
Title | Efficient Exemplar Word Spotting | Type | Conference Article | ||
Year | 2012 | Publication | 23rd British Machine Vision Conference | Abbreviated Journal | |
Volume | Issue | Pages | 67.1- 67.11 | ||
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Abstract | In this paper we propose an unsupervised segmentation-free method for word spotting in document images.
Documents are represented with a grid of HOG descriptors, and a sliding window approach is used to locate the document regions that are most similar to the query. We use the exemplar SVM framework to produce a better representation of the query in an unsupervised way. Finally, the document descriptors are precomputed and compressed with Product Quantization. This offers two advantages: first, a large number of documents can be kept in RAM memory at the same time. Second, the sliding window becomes significantly faster since distances between quantized HOG descriptors can be precomputed. Our results significantly outperform other segmentation-free methods in the literature, both in accuracy and in speed and memory usage. |
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ISSN | ISBN | 1-901725-46-4 | Medium | ||
Area | Expedition | Conference | BMVC | ||
Notes | DAG | Approved | no | ||
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DAG @ dag @ AGF2012 | Serial | 1984 | ||
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