The brightness and color of a surface depends on its contrast with nearby surfaces. For example, a gray surface can appear very light when surrounded by a black surface or dark when surrounded by a white surface. Some theories suggest that perceived surface brightness and color is represented explicitly by neural signals in cortical visual field maps; these neural signals are not initiated by t...

This paper aims at showing that performing color calibration of an RGB camera can be achieved even in the case where the optical system before the camera introduces strong color distortion. In the present case, the optical system is a microscope containing a halogen lamp, with a nonuniform irradiance on the viewed surface. The calibration method proposed in this work is based on an existing met...

This paper presents a technique for color-shading ooset surfaces of CSG models. The ooset surfaces are generated by rst scan converting the CSG model into a distance volume. A distance volume is a volume dataset where the value stored at each voxel is the shortest distance to the surface of the object being represented by the volume. Extracting iso-surfaces from the distance volume at various o...

One of the key tools in applying physics-based models to machine vision has been the analysis of color histograms. In the mid-1980’s it was recognized that the color histogram for a single inhomogeneous surface with highlights will have a planar distribution in color space. I t has since been shown that the colors do not fall randomly in a plane but form clusters a t specific points. Physics-ba...

A challenging issue associated with three-dimensional (3D) fringe patterns profilometry (FPP) is the unwrapping of phase maps resulting from color object surfaces. This paper proposes a new color-projection-based 3D FPP, making use of the three primary color channels [i.e., red, green, and blue (RGB)] associated with digital projectors. One channel (e.g., red) is used for projecting sinusoidal ...

Many theories of visual object perception assume the visual system initially extracts borders between objects and their background and then "fills in" color to the resulting object surfaces. We investigated the transformation of chromatic signals across the human ventral visual stream, with particular interest in distinguishing representations of object surface color from representations of chr...

A computer graphic program for organizing and displaying the colors in a paint collection is presented. A virtual representation for the traditional color card fan deck is described. This interactive program provides a lightness, chroma and hue interface for selecting a color from the collection. Software for visualizing a paint color on a three dimensional surface is also discussed. This tool ...

background: gingival involvement is commonly seen in lichen planus, a chronic mucocutaneous infl ammatory condition of the stratifi ed squamous epithelia. it is often painful and may undergo malignant transformation and thus warrants early diagnosis and prompt treatment. the aim of this study is to evaluate the use of a bioresorbable membrane (polyglactin 910) in the management of erosive liche...

Color-based object selection - for instance, looking for ripe tomatoes in the market - places demands on both perceptual and memory processes: it is necessary to form a stable perceptual estimate of surface color from a variable visual signal, as well as to retain multiple perceptual estimates in memory while comparing objects. Nevertheless, perceptual and memory processes in the color domain a...