In this paper we evaluate several extensions of Local Binary Patterns to color images. In particular, we investigate their robustness with respect to changes in the illuminant color temperature. To do so, we recovered the spectral reflectances of 1360 texture images from the Outex 13 data set. Then, we rendered the images as if they were taken under 33 different illuminants. For each combinatio...

An application of multispectral imaging in multimedia is presented. We describe a system for the acquisition of multispectral images using a CCD camera with carefully selected optical filters. We further discuss how the surface spectral reflectance of the imaged objects may be reconstructed from the camera response. We then present an application where the acquired multispectral images are used...

Interreflections in a scene can be exploited to improve upon surface and illuminant spectral estimation. In this paper, we present a novel maximum entropy approach to spectral color constancy in the presence of interreflections. Previous approaches employ linear model representations of surface and illuminant spectra. Such representations are not always practical as a database of spectra has to...

Lighting studies that take into account the age of inhabitants an area and are related to circadian light difficult find. This study aims simplify a method approximately compute reaching retina based on photopic illuminance corneal plane considering optical density aging crystalline lens. As example this proposed method, calculations were performed with both D65 A standard illuminants, showing ...

Abstract Environmental lighting applications include smart technologies with energy efficiency, zero toxic elements production, decreased number of luminaires, longer life span, etc. While the research is focused on performance and requirements there must be attention for users’ wellbeing even if consumption raised. One important aspect colour rendering, which defined as “effect an illuminant a...

This paper uses theory, simulation and laboratory experiment to investigate the directional filter on Kube and Pentland’s linear reflectance model which presents the image directionality as a product of the illuminant direction and surface directionality. As a result, a surface rotation is not equivalent to an image rotation if the illuminant is not rotated. It can be seen that the directional ...

In this paper, a robust illuminant estimation algorithm for color constancy is proposed. Considering the drawback of the well-known max-RGB algorithm, which regards only pixels with the maximum image intensities, we explore the representative pixels from an image for illuminant estimation: The representative pixels are determined via the intensity bounds corresponding to a certain percentage va...

We ran a control experiment in this study with the same experimental design as Ho, Landy, & Maloney (2006): we varied the angle between the punctate light source and the surface, but the viewer’s viewpoint was always fronto-parallel. The results shown in the following tables and figure demonstrate that observers in this study exhibited the same roughness judgment biases as observers in our prev...

We describe spectral estimation principles that are useful for color balancing, color conversion, and sensor design. The principles extend conventional estimation methods, which rely on linear models of the input data, by characterizing the distribution or structure of the linear model coefficients. When the linear model coefficients of the input data are highly structured, it is possible to im...

In this paper we present a new method of watermarking devoted to color images. Watermarking technics generally sign images by introducing changes that are imperceptible to the human eye, but are easily recoverable by a computer program. The locations in the image where the signature is embedded are determined by a secret key in order to prevent possible attacks by pirates or alterations due to ...