This paper compares two methods for estimating illumination distributions from shadows: methods using self shadows and cast shadows. The cast shadow method provides an effective framework for recovering illuminations in a real scene utilizing variations of image brightnesses inside shadows cast by an occluding object of known shape. The shadow surface is typically the same plane on which the ob...

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 ...

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 ...

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...

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...

This paper presents fast and robust per-sample correct shadows for WebGL platform. The algorithm is based on silhouette shadow volumes and it rivals the standard shadow mapping performance. Our performance is usually superior when compared with high resolution shadow maps. Moreover, it does not suffer from a number of artefacts of shadow mapping and always provides per-pixel correct results. We...

Shadow mapping is widely used in computer graphics for efficiently rendering shadows in real-time applications. Shadow maps cannot be filtered as regular textures, thus their limited resolution can cause severe shadow map discretization artifacts in the rendered images. To solve this problem, several techniques have been proposed, including variance shadow maps (VSM) and exponential shadow maps...

We present an approach to efficiently reduce shadow map resolution while retaining high quality hard shadows. In the first step, we generate a list of sample points that are seen from the camera and then project these into light space, much like Alias-free Shadow Maps. In the next step, we analyze the list of sample points on the GPU to construct a tight light frustum for shadow rendering. Afte...

Shadow mapping is a very useful tool for generating shadows in many real-time rendering settings and is even used in some off-line renderers. One of the difficulties when using a shadow map is obtaining a sufficiently dense sampling on shadowed surfaces to minimize shadow aliasing. Endlessly upping the light-image resolution is not always a viable option. In this paper we describe a shadow mapp...

This paper introduces a new set of orbits, the “Repeated Shadow Track Orbits.” In these orbits, the shadow of a spacecraft on the Earth visits the same locations periodically every desired number of days. The J2 perturbation is utilized to synchronize the spacecraft shadow motion with both the Earth rotational motion and the Earth-Sun vector rotation. Motivation for the design of new shadow tra...