A ranked poset P is a Macaulay poset if there is a linear order of the elements of P such that for any m; i the set C(m; i) of the m (with respect to) smallest elements of rank i has minimum{sized shadow among all m{element subsets of the i{th level, and the shadow of C(m; i) consists of the smallest elements of the (i ? 1){st level. P is called shadow{increasing if for all m; i the shadow of C...

A typical shadow-eliminating algorithm is presented in this paper. Algorithms for vehicle detection, edge detection and shadow detection are also given. If the shadow is not separated from the vehicle, the next traffic control processes, like vehicle classification, tracking and speed calculation, will be rather difficult. Our approach for shadow processing runs in real time in low-cost hardwar...

Shadow detection is of broad interest in computer vision. In this article, a new shadow detection method for single color images in outdoor scenes is proposed. Shadows attenuate pixel intensity, and the degrees of attenuation are different in the three RGB color channels. Previously, we proposed the Tricolor Attenuation Model (TAM) that describes the attenuation relationship between shadows and...

Soft shadows provide important information to viewers about spatial relationships between objects. Generating accurate soft shadows in real time has been a focus of research in computer graphics. Shadow mapping is a standard way of generating hard shadows in real time and several methods including Smoothies [Chan and Durand 2003] and penumbra maps [Wyman and Hansen 2003] extend the standard sha...

The main objective of this project was to implement the real-time soft shadow volume method proposed by Ulf Assarsson and Thomas Akenine-Möller in their SIGGRAPH 2003 paper [1]. The original method is proposed as a hardware implementation. However due to time constraints, the implementation in this project does not employ a graphics accelerator card for the soft shadow rendering. Fortunately, t...

In this paper we present a novel method for shadow removal in single images. For each shadow region we use a trained classifier to identify a neighboring lit region of the same material. Given a pair of lit-shadow regions we perform a region relighting transformation based on histogram matching of luminance values between the shadow region and the lit region. Then, we adjust the CIELAB a and b ...

We present a new GPU pipeline for rendering per-pixel exact shadows that are cast by point lights and parallel lights. Our approach is hybrid in that it uses kD-tree accelerated ray-tracing to determine shadow-ray intersections, and rasterization to effectively reduce both the number of shadow rays to be traversed and the number of sub-spaces to be considered along each of these rays. To achiev...

Humans show great flexibility in adjusting their levels of cooperation to account for current and future circumstances. For example, levels of cooperation are higher if there is more competition at the level of the whole population than with interacting partners [1] and when individuals are likely to gain social prestige [2]. Humans also show the capacity to increase current levels of cooperati...

In system-level simulations of wireless communication systems, shadow fading is commonly modeled by spatial autocorrelation. Currently, shadow fading values are generated using a shadow fading map, which rasterizes the region of interest. This map is commonly generated at its full extent, although only a small part of it may be needed. In this paper we propose an approach for generating shadow ...