Perceptual processes, in computer or biological vision, require the computation of “maps” of quantitative values. The image itself is a “retinotopic map”: for each pixel of the image there is a value corresponding to the image intensity at this location. This is a vectorial value for color images. A step further, in early-vision, the retinal image contrast is computed at each location, allowing...

Figure 1. The April Fool’s hoax map from 1975. Developing an algorithm to 4-color planar maps leads to two interesting computational issues: 1. Devising an algorithm that will 4-color planar graphs. Since the proof that such an algorithm works would yield the 4-color theorem, one will have to deal with the fact that the algorithm is likely to be not proved to work. One hopes that it will simply...

We located clusters of color-selective neurons in macaque striate cortex, as mapped with optical imaging and confirmed with electrophysiological recordings. By comparing responses to an equiluminant red/green stimulus versus a high-contrast luminance stimulus, we were able to reveal a patchy distribution of color selectivity. Other color imaging protocols, when compared with electrophysiologica...

OBJECTIVE To investigate the effect of beverages' temperature on the surface roughness, hardness, and color stability of a composite resin. MATERIALS AND METHODS Fifty specimens of the Filtek Z250 composite (3M ESPE, Dental Products, St.Paul, MN, USA) were prepared and initial roughness, microhardness, and color were measured. Then the specimens were randomly divided into five groups of 10 sp...

This review describes measurements of visual field maps and color signals in human visual cortex. One of the most exciting advances in recent years has been the ability to measure more than a dozen visual field maps in human visual cortex. These maps are grouped into small clusters that share a common eccentricity representation; we speculate that maps within a cluster have shared visual functi...

In this paper we consider the problem of estimating a 3D motion field using multiple cameras. In particular, we focus on the situation where a depth camera and one or more color cameras are available, a common situation with recent composite sensors such as the Kinect. In this case, geometric information from depth maps can be combined with intensity variations in color images in order to estim...

The objective of this study was to evaluate the effect of two bleaching agents (10% and 35% hydrogen peroxide) on the color stability and surface roughness of two composites, one nanohybrid and one nanoparticle. Specimens were polished, aged, stained, bleached and polished again. The action of the bleaching agents on the composites was analyzed using a profilometer (surface roughness) and a spe...

OBJECTIVES The aim of this study was to evaluate the effects of 3 commercially available mouth rinses on the color stability of 4 different resin-based composite restorative materials. METHODS Forty disc-shaped specimens (10x2 mm) were prepared from each of the following materials: A nanofill composite Filtek Supreme XT (3M/Espe, St. Paul, MN, USA); a packable low-shrinkage composite, AeliteL...