Various visual functions decline in ageing and even more so in patients with Alzheimer's disease (AD). Here we investigated whether the complex visual processes involved in ignoring illumination-related variability (specifically, cast shadows) in visual scenes may also be compromised. Participants searched for a discrepant target among items which appeared as posts with shadows cast by light-fr...

We present fast ray tracing of dynamic scenes in this paper with primary and shadow rays. We present a GPUfriendly strategy to bring coherency to shadow rays, based on previous work on grids as acceleration structures. We introduce indirect mapping of threads to rays to improve the performance of ray tracing on the GPU for the traversal and intersection steps. We also construct a light frustum ...

Shadow mapping has been a popular way of generating shadows in real-time applications, but it is still incapable of generating realistic real time soft shadows for area light. There is an algorithm for generating soft shadows for linear light with few samples, but the algorithm is not suitable for area light. In this article, the author presents a modified method to the shadow mapping algorithm...

Cast shadows are ubiquitous in the visual scene and they inform greatly about the scene's three-dimensional spatial layout. In the present study we investigated the ability of the visual system to detect the structural form of cast shadows using Glass patterns consisting of local dot-pairs or dipoles oriented appropriately to convey global structure. "Cast shadow" Glass patterns were constructe...

Vehicle detection is a fundamental task in Forward Collision Avoiding Systems (FACS). Generally, vision-based vehicle detection methods consist of two stages: hypotheses generation and hypotheses verification. In this paper, we focus on the former, presenting a feature-based method for on-road vehicle detection in urban traffic. Hypotheses for vehicle candidates are generated according to the s...

In this paper we propose a novel method for detecting and removing shadows from a single image thereby obtaining a high-quality shadow-free image. With minimal user assistance, we first identify shadowed and lit areas on the same surface in the scene using an illumination-invariant distance measure. These areas are used to estimate the parameters of an affine shadow formation model. A novel pyr...

Since precise shadows can be generated in real-time, graphics applications often use the shadow volume algorithm. This algorithm was limited to manifold casters, but recently has been extended to general non-manifold casters with oriented triangles. We provide a further extension to general non-manifold meshes and an additional extension to shadows of transparent casters. To achieve these, we f...

Two of the best methods to recognize silhouette to create real-time volume shadow in virtual environment are described in this paper. Volume shadow algorithm is implemented for virtual environment with moveable illuminated light source. Triangular method and the Visible-non visible method are introduced. The recent traditional silhouette detection and implementation techniques used in volume sh...

In this paper we abandon the regular structure of shadow maps. Instead, we transform the visible pixels P(x,y,z) from screen space to the image plane of a light source P′(x′,y′,z′). The (x′,y′) are then used as sampling points when the geometry is rasterized into the shadow map. This eliminates the resolution issues that have plagued shadow maps for decades, e.g., jagged shadow boundaries. Inco...

Shadow mapping has been extensively used for real-time shadow rendering in 3D computer games, though it suffers from the inherent aliasing problems due to its image-based nature. The aliasing errors in shadow mapping consist of perspective aliasing error and projection aliasing error. In this paper, we propose a novel shadow-map reparameterization to reduce perspective aliasing for varying view...