The paper presents a new data structure called a shadow pyramid for storing 3D objects to reduce the shadow-testing time during ray tracing. For each primitive object that first intersects a ray, a shadow pyramid is constructed in which all the candidate objects that possibly block the path from the relevant light source to any point on the primitive object are registered. Shadow testing of. th...

HYPOTHESES Task performance improves with the use of a balanced degree of shadow and illumination compared with no or maximum shadow contrast; and overhead shadow-casting illumination is better than side illumination. DESIGN The standard task entailed touching target points on an undulating surface by using a surgical hook. Each run consisted of 13 target points in a random sequence. Five set...

A user-centric method for fast, interactive, robust, and high-quality shadow removal is presented. Our algorithm can perform detection and removal in a range of difficult cases, such as highly textured and colored shadows. To perform detection, an on-the-fly learning approach is adopted guided by two rough user inputs for the pixels of the shadow and the lit area. After detection, shadow remova...

Shadow effects have drawn much attention by researchers with increasing use of high-resolution remote sensing images of urban areas. For correction or compensation to pixels that falling in shadow areas due to the existence of vertically standing objects such as buildings and trees, quantitative analysis of shadow effects is essential. In this paper, we proposed an object-based approach for pre...

This paper presents a methodology to automatically detect and remove the shadows in high-resolution urban aerial images for urban GIS applications. The system includes cast shadow computation, image shadow tracing and detection, and shadow removal. The cast shadow is computed from digital surface model (DSM) and the sun altitudes. Its projection in the pseudo orthogonal image is determined by r...

We present an algorithm for artistically modifying physically based shadows. With our tool, an artist can directly edit the shadow boundaries in the scene in an intuitive fashion similar to freeform curve editing. Our algorithm then makes these shadow edits consistent with respect to varying light directions and scene configurations, by creating a shadow mesh from the new silhouettes. The shado...

Shadows are important to computer graphics because they add realism and help the viewer identify spatial relationships. Shadows are also useful story-telling devices. For instance, artists carefully choose the shape, softness, and placement of shadows to establish mood or character. Many shadow generation techniques developed over the years have been used successfully in offline movie productio...

Shadow Information Technology (IT) occurs when users develop systems outside of the central information technology department. It provides both benefits and risks. Users procuring shadow IT often do not consider integration with existing enterprise architecture, privacy and security protection, maintenance cost, and legal ramifications. Problems with shadow IT must often be resolved by central ...

We present a hybrid algorithm for rendering hard shadows accurately and efficiently. Our method combines the strengths of shadow maps and shadow volumes. We first use a shadow map to identify the pixels in the image that lie near shadow discontinuities. Then, we perform the shadow-volume computation only at these pixels to ensure accurate shadow edges. This approach simultaneously avoids the ed...

This paper proposes real-time interactive systems illuminating your shadows cast on the floor, which we name “Graphic Shadow.” They will make you experience an exciting space of interaction performing an illusion on your own shadow.