The perception of surface gloss depends on specular highlights but little is understood about how the visual system distinguishes specular highlights from other luminance maxima generated by variations in pigmentation or illumination. It has been argued that diffuse shading gradients provide information for identifying specular highlights. Specular highlights typically share the orientation of ...

ÐThis paper makes two contributions to the problem of needle-map recovery using shape-from-shading. First, we provide a geometric update procedure which allows the image irradiance equation to be satisfied as a hard constraint. This not only improves the data closeness of the recovered needle-map, but also removes the necessity for extensive parameter tuning. Second, we exploit the improved eas...

CONCLUSION The shape from shading and optical flow are implemented to three-dimensional (3D) reconstruction. OBJECTIVE Solve the problem of 3D reconstruction in endoscope imaging. METHOD One of the fundamental approaches in the domain of computer vision is shape from shading. This algorithm was proposed to obtain the shape of an object from a single intensity image. Because of the severe co...

Shading the greenhouses is necessary in summer to reduce the solar radiation load. This however generates a considerable amount of thermal radiation heat load that needs to be removed via cooling systems. This study aimed to evaluate the effect of different shading configurations on the solar and thermal radiation in a greenhouse. Nets at four different locations were employed to shade the roof...

Partial shading is an unavoidable condition which significantly reduces the efficiency and stability of a photovoltaic (PV) system. When partial shading occurs the system has multiple-peak output power characteristics. In order to track the global maximum power point (GMPP) within an appropriate period a reliable technique is required. Conventional techniques such as hill climbing and perturbat...

Three human observers estimated the illumination direction for samples of random Gaussian surfaces illuminated by a collimated beam from random directions. These stimuli appear as 'texture' due to shading and shadowing (the surface on the microscale was Lambertian of uniform albedo; thus texture appears only through shading and shadowing). We found that observers were able to estimate the azimu...

Due to Increasing demands of cartoon style In many areas of computer graphic aspects, this paper presents a simple stylized shading technique to enhance the cartoonlsh appearance In two aspects. First, a new toon-illumlnation model Is developed to emphasize the boundaries between diffuse reflection part and specular reflection part in the phong illumination model. The new discrete shading will ...

The goal of the I.M.O.G.E.N.E. project is to define a real time graphics system. We focus on true real time display, images being computed at frame rate, i.e 50 (or 60) times a second. The I.M.O.G.E.N.E. machine uses no frame buffer. We use a massive object parallelism; the graphics module is made of a large number of object-processors, each one handling one graphics primitive at pixel rate in ...

Computer image generation systems often represent curved surfaces as a mesh of planar polygons that are shaded to restore a smooth appearance. In software rendering Phong shading has been one of the most successful algorithms, because it can realistically handle specular materials. Since it requires the rendering equation to be evaluated for each pixel, its hardware support poses problems. This...

Partial shading of a PV installation has a disproportionate impact on its power production. This paper presents background and experimental results from a single string grid-tied PV system, operated under a variety of shading conditions. In this configuration a shadow can represent a reduction in power over 30 times its physical size. Results are presented relating size and positions of shading...