The efficient evaluation of visibility in a three-dimensional scene is a longstanding problem in computer graphics. Visibility evaluations come in many different forms: figuring out what object is visible in a pixel; determining whether a point is visible to a light source; or evaluating the mutual visibility between 2 surface points. This paper provides a new, experimental view on visibility, ...

Illumination effects, including shadows and varying lighting, makes the problem of face recognition challenging. Experimental and theoretical results show that the face images under different illumination conditions lie in a low-dimensional subspace, hence principal component analysis (PCA) or low-dimensional subspace techniques have been used. Following this spirit, we propose new techniques f...

This paper describes a method for recognizing partially occluded objects to realize a bin-picking task under different levels of illumination brightness by using the eigen-space analysis. In the proposed method, a measured color in the RGB color space is transformed into the HSV color space. Then, the hue of the measured color, which is invariant to change in illumination brightness and directi...

It is argued that global illumination should be modeled separately from other incidents that change the appearance of objects. The eeects of intensity variations of the global illumination are discussed and constraints deduced that restrict the shape of a function that maps the histogram of a template to the histogram of an image location. This approach is illustrated for simple pattern matchin...

We address in this paper the issue of computing diffuse global illumination solutions for animation sequences. The principal difficulties lie in the computational complexity of global illumination, emphasized by the movement of objects and the large number of frames to compute, as well as the potential for creating temporal discontinuities in the illumination, a particularly noticeable artifact...

We present a method for real-time clustering of VPLs obtained from Reflective Shadow Maps (RSM). The clusters are treated as area light sources and used to approximate indirect illumination. The spatial extent of a cluster is used to deduce the shape and size of the respective area light source. Our method is fully GPU-based and avoids flickering by temporally coherent reinitialization of the c...

Rendering animations of scenes with deformable objects, camera motion, and complex illumination, including indirect lighting and arbitrary shading, is a long-standing challenge. Prior work has shown that complex lighting can be accurately approximated by a large collection of point lights. In this formulation, rendering of animation sequences becomes the problem of efficiently shading many surf...

A new photometric method is proposed fo r determining the 3-D shape of t he object from multiple shading Images under the point light source illumination. When the surface is t he perfect diffuser with the uniform reflectance, an algorithm fo r the determination of 3-D shape with positions is developed by using the method of least squares and basing on the principle of the monocular vision and ...

We describe illumination spectra in forests and show that they can be accurately recovered from recorded digital video images. Natural illuminant spectra of 238 samples measured in temperate forests were characterized by principal-component analysis. The spectra can be accurately approximated by the mean and the first two principal components. Compared with illumination under open skies, the lo...

In this paper three problems related to the analysis of facial images are addressed: the estimation of the illuminant direction, the compensation of illumination eeects and, nally, the recovery of the pose of the face, restricted to in-depth rotations. The solutions proposed for these problems rely on the use of computer graphics techniques to provide images of faces under diierent illumination...