The aliasing problem in computer-generated shaded images

Abstract

Certain defects, such as jagged edges and disappearing detail, have long been an annoyance in digitally generated shaded images. Although increasing the resolution or defocusing the display can attenuate them, an understanding of these defects leads to more effective methods. This paper explains the observed defects in terms of the aliasing phenomenon inherent in sampled signals and discusses prefiltering as a recognized cure. A method for evaluating filters is presented, the application of prefiltering to hidden-surface algorithms is discussed, and an implementation of a filtering tiler is shown accompanied by examples of its effectiveness.

Measuring the deformation of a ferrogel sphere in a homogeneous magnetic field

“…The circle is located utilizing a normalized correlation technique [21], where the correlation between the gradient of the image and a circle is maximized. The gradient is estimated by the Sobel operator [22], and the circle is rasterized with anti-aliasing provided by a Gaussian filter [23]. This method is able to extract the radius and the coordinates of the center with subpixel resolution.…”

An adaptive supersampling method

“…Examples of FSB methods include supersampling z-buer method [7] in which the scene is supersampled and then ltered down into the output resolution. The problems of this method are that it requires a lot of memory to store the supersampled image and a lot of processing time.…”

Realism in Computer Graphics: A Survey

“…The sampling theory outlined above was first applied to computer graphics by Crow 13 in the middle '70's. He computed the area coverage of a polygon and used a triangular filter to get a weight for the contribution of that polygon to the pixel.…”