Shading

About: Shading is a research topic. Over the lifetime, 5048 publications have been published within this topic receiving 66578 citations.

Illumination for computer generated pictures

Abstract: The quality of computer generated images of three-dimensional scenes depends on the shading technique used to paint the objects on the cathode-ray tube screen. The shading algorithm itself depends in part on the method for modeling the object, which also determines the hidden surface algorithm. The various methods of object modeling, shading, and hidden surface removal are thus strongly interconnected. Several shading techniques corresponding to different methods of object modeling and the related hidden surface algorithms are presented here. Human visual perception and the fundamental laws of optics are considered in the development of a shading rule that provides better quality and increased realism in generated images.

Shape from shading

Abstract: Understanding how the shape of a three dimensional object may be recovered from shading in a two-dimensional image of the object is one of the most important - and still unresolved - problems in machine vision. Although this important subfield is now in its second decade, this book is the first to provide a comprehensive review of shape from shading. It brings together all of the seminal papers on the subject, shows how recent work relates to more traditional approaches, and provides a comprehensive annotated bibliography.The book's 17 chapters cover: Surface Descriptions from Stereo and Shading. Shape and Source from Shading. The Eikonal Equation: some Results Applicable to Computer Vision. A Method for Enforcing Integrability in Shape from Shading Algorithms. Obtaining Shape from Shading Information. The Variational Approach to Shape from Shading. Calculating the Reflectance Map. Numerical Shape from Shading and Occluding Boundaries. Photometric Invariants Related to Solid Shape. Improved Methods of Estimating Shape from Shading Using the Light Source Coordinate System. A Provably Convergent Algorithm for Shape from Shading. Recovering Three Dimensional Shape from a Single Image of Curved Objects. Perception of Solid Shape from Shading. Local Shading Analysis Pentland. Radarclinometry for the Venus Radar Mapper. Photometric Method for Determining Surface Orientation from Multiple Images.Berthold K. P. Horn is Professor of Electrical Engineering and Computer Science at MIT. He has presided over the field of machine vision for more than a decade and is the author of "Robot Vision. "Michael Brooks is Reader in Computer Science at The Flinders University of South Australia. "Shape from Shading" is included in the Artificial Intelligence series, edited by Michael Brady, Daniel Bobrow, and Randall Davis.

Power loss due to soiling on solar panel: A review

Abstract: The power output delivered from a photovoltaic module highly depends on the amount of irradiance, which reaches the solar cells. Many factors determine the ideal output or optimum yield in a photovoltaic module. However, the environment is one of the contributing parameters which directly affect the photovoltaic performance. The authors review and evaluate key contributions to the understanding, performance effects, and mitigation of power loss due to soiling on a solar panel. Electrical characteristics of PV (Voltage and current) are discussed with respect to shading due to soiling. Shading due to soiling is divided in two categories, namely, soft shading such as air pollution, and hard shading which occurs when a solid such as accumulated dust blocks the sunlight. The result shows that soft shading affects the current provided by the PV module, but the voltage remains the same. In hard shading, the performance of the PV module depends on whether some cells are shaded or all cells of the PV module are shaded. If some cells are shaded, then as long as the unshaded cells receive solar irradiance, there will be some output although there will be a decrease in the voltage output of the PV module. This study also present a few cleaning method to prevent from dust accumulation on the surface of solar arrays.

Shade trees

Abstract: Shading is an important part of computer imagery, but shaders have been based on fixed models to which all surfaces must conform. As computer imagery becomes more sophisticated, surfaces have more complex shading characteristics and thus require a less rigid shading model. This paper presents a flexible tree-structured shading model that can represent a wide range of shading characteristics. The model provides an easy means for specifying complex shading characteristics. It is also efficient because it can tailor the shading calculations to each type of surface.