C. Alejandro Párraga

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Many successful models for predicting attention in a scene involve three main steps: convolution with a set of filters, a center-surround mechanism and spatial pooling to construct a saliency map. However, integrating spatial information and justifying the choice of various parameter values remain open problems. In this paper we show that an efficient model(More)
A new multiresolution wavelet model is presented here, which accounts for brightness assimilation and contrast effects in a unified framework, and includes known psychophysical and physiological attributes of the primate visual system (such as spatial frequency channels, oriented receptive fields, contrast sensitivity function, contrast non-linearities, and(More)
How different are two images when viewed by a human observer? There is a class of computational models which attempt to predict perceived differences between subtly different images. These are derived from theoretical considerations of human vision and are mostly validated from psychophysical experiments on stimuli, such as sinusoidal gratings. We are(More)
How different are two images when viewed by a human observer? Such knowledge is needed in many situations including when one has to judge the degree to which a graphics representation may be similar to a high-quality photograph of the original scene. There is a class of computational models which attempt to predict such perceived differences. These are(More)
Computational colour constancy tries to solve the problem of recovering the illuminant of a scene from an acquired image. The most popular algorithms developed to deal with this problem use heuristics to select a unique solution from within the feasible set. Their performance has shown that there is still a long way to go to globally solve this problem as a(More)
We propose a saliency model termed SIM (saliency by induction mechanisms), which is based on a low-level spatiochromatic model that has successfully predicted chromatic induction phenomena. In so doing, we hypothesize that the low-level visual mechanisms that enhance or suppress image detail are also responsible for making some image regions more salient.(More)
Tone-mapping operators (TMO) are designed to generate perceptually similar low-dynamic range images from high-dynamic range ones. We studied the performance of fifteen TMOs in two psy-chophysical experiments where observers compared the digitally generated tone-mapped images to their corresponding physical scenes. All experiments were performed in a(More)
Q3 ds: 20 Display calibration 21 Psychophysics 22 Perceptual 23 Visual gamma correction 24 Luminance matching 25 Observer-based calibration 26 2 7 a b s t r a c t 28 A method for estimating the non-linear gamma transfer function of liquid–crystal displays (LCDs) 29 without the need of a photometric measurement device was described by Xiao et al. (2011) [1].(More)