One approach to change detection that is insensitive to illumination brightness and spectral changes uses properties of color imagery. This approach does not appear to have been previously investigated, and this paper asks: “What is the most appropriate metric for detecting changes in color imagery?”. We define and compare six image difference functions, mainly based on RGB and HSV image repres...

We present a method for rendering approximate soft shadows and diffuse indirect illumination in dynamic scenes. The proposed method approximates the original scene geometry with a set of tightly fitting spheres. In previous work, such spheres have been used to dynamically evaluate the visibility function to render soft shadows. In this paper, each sphere also acts as a low-frequency secondary l...

Flash photography is commonly used in low-light conditions to prevent noise and blurring artifacts. However, flash photography commonly leads to a mismatch between scene illumination and flash illumination, due to the bluish light that flashes emit. Not only does this change the atmosphere of the original scene illumination, it also makes it difficult to perform white balancing because of the i...

Augmented reality technology is becoming important in developing visual representation of virtual environment. In augmented reality environment, the most difficult problem is to render the virtual object with illumination which is consistent with the illumination and shadow of the real environment. Without the consistent illumination, the realism of augmented reality environment will be reduced...

We propose a method to stabilize illumination color estimation by using the idea of an “Illumination line segment”. It is a finite line where every illumination color exists in the color space. By restricting the estimated illumination colors to be on this line, the method succeeds in making the estimation more robust and accurate. The method is based on our past work, while it uses direct calc...

Moving objects in image sequences acquired by a static camera can be detected by analyzing the grey–level difference between successive frames. Direct motion detection, however, will also detect fast variations of scene illumination. This paper describes a method for motion detection that is considerably less sensitive to time–varying illumination. It is based on combining a motion detection al...

This study investigated the effects of lighting color, illumination intensity, and text color on visual performance. Experiment 1 conducted character identifying test and Experiment 2 conducted reading comprehension test. Results of experiment 1 indicated that all the three independent variables had significant effects on mean percentage of character identification. Mean percentage was best und...

This paper describes a robust method for estimating, in a reliable manner, the illumination distribution of a real scene from shadows in a given image. In general, shadows in a scene are caused by the occlusion of incoming light; image brightness inside shadows have a great potential for providing distinct clues to the illumination distribution of the scene. Taking advantage of this fact, we re...

3D-2D face recognition is beginning to gain attention from the research community. It takes advantage of 3D facial geometry to normalize the head pose and registers it into a canonical 2D space. In this paper, we present a novel illumination normalization approach for 3D-2D face recognition which does not require any training or prior knowledge on the type, number, and direction of the lighting...

We present a simple but effective algorithm to simulate plant growth in a realistic way, taking into account illumination, spatial occupancy and the nearby presence of other plants. The basic idea of our algorithm is to simulate light flow during all stages of plant development, by tracing virtual photons emitted by light sources in the same way as it is done in many global illumination algorit...