In this paper we present an image-based algorithm to render visually plausible anti-aliased soft shadows in real time. Our technique employs a new shadow pre-filtering method based on an extended exponential shadow mapping theory. The algorithm achieves faithful contact shadows by adopting an optimal approximation to exponential shadow reconstruction function. Benefiting from a novel overflow f...

Methods are proposed to record the way in which objects respond to varying illumination—to capture and reproduce varying shadows and highlights and thus give the illusion that absent objects are present behind a ‘‘window’’ into which people may shine arbitrary lights of their choice. When the recording is viewed under two separate point sources, one sees a reproduction of the original scene wit...

We present an automated numerical method of compensating for retinal shadows in the choroid. In this method, signal extinction caused by retinal vessels is estimated by subtracting median A-scans obtained from beneath the retinal vessels and A-scans from the surrounding area. Adding the obtained offset vector to A-scans from beneath the retinal vessels allows compensating for shadows in the cho...

In applications requiring objects extraction, cast shadows induce shape distortions and object fusions interfering performance of high level algorithms in video surveillance system. Shadow elimination allows to improve the performances of video object extraction, tracking and description tools. In this work, an approach to automatic shadow detection and extraction is proposed, which operates mu...

We present a novel combination photometric stereo which can estimate surface normals precisely even for images including shadows and specular reflection. We can use photometric stereo if there are more than three input images. Therefore we can employ photometric stereo with nC3 combinations for n input images. We make 3D distribution of albedos and surface normals estimated from pixel intensiti...

In typical machine vision problems such as quality control or object location, it is often the case that elements of interest are small protuberances over a surface. We present an innovative and robust approach aiming at detecting such protuberances. Its basic ideas are: a) to detect the shadows produced by the protuberances, b) to use several light sources simultaneously to enhance detection. ...

Designing an ecologically responsible EcoCity of 550,000 people begins by confining it to 8500 ha, which spares surrounding land for farming and for Nature. Because an American diet requires 126,000 ha and even a survival diet needs more cropland than can be found inside its boundaries, EcoCity will cast shadows of farming outside its limits. EcoCitizens will cast wider shadows if farmers grow ...

We present a system for interactive shadow editing from single images which includes the manipulations of shape, distribution, sharpness and darkness of shadows according to the features of existing shadows. We first obtain a shadow-free image, shadow boundary and its registered sparse shadow scales using an existing shadow removal method. The modifiable features of the shadow are synthesised f...

In this paper, we introduce a simple but efficient cue for the extraction of shadows from a single color image, the bright channel cue. We discuss its limitations and offer two methods to refine the bright channel: by computing confidence values for the cast shadows, based on a shadow-dependent feature, such as hue; and by combining the bright channel with illumination invariant representations...

A proactive secret sharing scheme is a method of sharing a secret among a set of participants. And, the corresponding shadows can be periodically renewed under the premise of never changing the shared secret. However, in the most existing proactive secret sharing schemes, only one secret can be shared during one secret sharing process. The proposed scheme describes PMSS, a new way to share mult...