A Lixel for every Pixel
نویسندگان
چکیده
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 mapping technique that guarantees, that over a small number of chosen planes of interest (such as a floor and a wall), the shadow map is, in fact, perfectly sampled, ie. for each pixel in the viewer camera, there will be exactly one lixel in the shadow map that samples the exact same geometric point.
منابع مشابه
Kernel Density Estimation of traffic accidents in a network space
A standard planar Kernel Density Estimation (KDE) aims to produce a smooth density surface of spatial point events over a 2-D geographic space. However the planar KDE may not be suited for characterizing certain point events, such as traffic accidents, which usually occur inside a 1-D linear space, the roadway network. This paper presents a novel network KDE approach to estimating the density o...
متن کاملOn the Pixel Expansion of Hypergraph Access Structures in Visual Cryptography Schemes
In a visual cryptography scheme, a secret image is encoded into n shares, in the form of transparencies. The shares are then distributed to n participants. Qualified subsets of participants can recover the secret image by superimposing their transparencies, but non-qualified subsets of participants have no information about the secret image. Pixel expansion, which represents the number of subpi...
متن کاملSteganalysis of embedding in difference of image pixel pairs by neural network
In this paper a steganalysis method is proposed for pixel value differencing method. This steganographic method, which has been immune against conventional attacks, performs the embedding in the difference of the values of pixel pairs. Therefore, the histogram of the differences of an embedded image is di_erent as compared with a cover image. A number of characteristics are identified in the di...
متن کاملیک روش جدید افزایش دقت مکانی تصاویر سنجش از دور با استفاده از جدول جستجو
Different methods have been proposed to increase the image spatial resolution by mixed pixels decomposition. These methods can be divided into two groups. Some research have been attempted to obtain percentages of sub pixels and the other try to obtain their locations. These methods and their problems will be examined in this study. Common methods are reviewed with more emphasis. Finally, a new...
متن کاملیک الگوریتم جدید برای تشخیص نواحی پوشش‌گیاهی و سایه در تصاویر هوایی/ماهواره‌ای با تفکیک مکانی بالا بر اساس روش تحلیل مولفه‌های اصلی
Evaluation of vegetation cover by using the remote sensing data can provide enhanced results with less time and expense. In this paper, we propose a new automatic algorithm for detection of vegetation and shadow regions in high-resolution satellite/aerial images. It uses only color channels of the image and involves two modeling and evaluation phases. In the modeling phase, after extracting col...
متن کامل