نتایج جستجو برای: illuminant
تعداد نتایج: 836 فیلتر نتایج به سال:
Predicting how the LMS cone response to light reflected from a surface changes with changing lighting conditions is a long-standing and important problem. It arises in white balancing digital imagery, and when re-rendering printed material for viewing under a second illuminant (e.g., changing from D65 to F11). Von Kries scaling is perhaps the most common approach to predicting what LMS cone res...
Some theories of surface-colour perception assume that observers estimate the illuminant on a scene so that its effects can be discounted. A critical test of this interpretation of colour constancy is whether surface-colour matching is worse when the number of surfaces in a scene is so small that any illuminant estimate is unreliable. In the experiment reported here, observers made asymmetric c...
In typical display viewing conditions, observers are perceptible as different color temperatures at the luminance levels, illuminant, and reference white of display. In the same luminance level, adaptive neutral point(NP) of human visual system(HVS) is determined by not only illuminant’s correlated color temperature(CCT) but also display reference white. However, if luminance level is not as hi...
In this study human color constancy was tested for two-dimensional (2D) and three-dimensional (3D) setups with real objects and lights. Four different illuminant changes, a natural selection task and a wide choice of target colors were used. We found that color constancy was better when the target color was learned as a 3D object in a cue-rich 3D scene than in a 2D setup. This improvement was i...
ÐThis paper considers the problem of illuminant estimation: how, given an image of a scene, recorded under an unknown light, we can recover an estimate of that light. Obtaining such an estimate is a central part of solving the color constancy problemÐthat is of recovering an illuminant independent representation of the reflectances in a scene. Thus, the work presented here will have application...
Given LMS cone quantum catches from a surface under a first illuminant what is the best method of predicting what the corresponding quantum catches will be for the same surface under a second illuminant given only the quantum catches of a white surface under both illuminants? The von Kries rule is one well known method. In this paper, two new prediction methods along with a variation on an exis...
A robust approach to recovery of shape from shading information is presented. Assuming uniform albedo and Lambertian surface for the imaging model, we first present methods for the estimation of illuminant direction and surface albedo. The illuminant azimuth is estimated by averaging local estimates. The illuminant elevation and surface albedo are estimated from image statistics. Using the esti...
The visual system needs to discount the influence of an illuminant to achieve color constancy. Uchikawa et al. [J. Opt. Soc. Am. A29, A133 (2012) showed that the luminance-balance change of surfaces in a scene contributes to illuminant estimation; however, its effect was substantially less than the chromaticity change. We conduct three experiments to reinforce the previous findings and investig...
The aim of computational color constancy is to estimate the actual surface color in an acquired scene disregarding its illuminant. Many solutions try to first estimate the illuminant and then correct the image with the illuminant estimate. Based on the linear image formation model, we propose in this work a new strategy to estimate the illuminant. Inspired by the feedback modulation from horizo...
Surface metamerism is the phenomenon whereby two spectrally different reflectances induce the same response under fixed conditions (observer and illuminant) and induce different responses when recording conditions change. Metamerism arises due to the discrepancy between the degrees of freedom of the observer (usually three) and the degrees of freedom needed to represent surface spectral reflect...
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