Texture filtering method and device based on anisotropy

Abstract

The invention provides a texture filtering method based on anisotropy, comprising the following steps of: carrying out MIP-MAP (Multum In Parvo Map) prefiltering on a texture image; considering an image in a screen space as a circle with a unit pixel as radius, projecting the pixel into the texture space and carrying out approximation by using an ellipse; calculating minor axis radius, macro axis radius and an included angle between the macro axis radius and a u-axis of the ellipse; determining a sampling layer L in a texture lookup table according to the calculated minor axis radius; determining the sample quantity in the sampling layer L and the positions of the macro axis sampling points along the ellipse according to the minor axis radius, the macro axis radius and the included angle between the macro axis radius and the u-axis, and sampling in the sampling layer L; sampling in a sampling layer L+1 along the macro axis of the ellipse according to the sampling quantity of the sampling layer L+1; carrying out linear interpolation on color values obtained from the sampling layer L and the sampling layer L+1 to finally obtain the color value. By adopting 1 / 4 sampling quantity in the L layer as the sampling quantity in the L+1 layer, the invention avoids oversampling and ensures that the texture can be still kept clear when the texture view angle is far away from the observation points.

Description

technical field [0001] The invention relates to the field of image processing, in particular to an anisotropy-based texture filtering method and device. Background technique [0002] In order to speed up the texture mapping and reduce the calculation consumption of the mapping process, the pre-filtered texture process is often used, so that each pixel only needs to extract a small number of pre-filtered sampling points for calculation, thereby improving the calculation effect. [0003] In the prior art, a double integral can generally be used to define pre-filtering, that is, g(x, y)=∫∫f(x, y) h(x-u, y-v) du dv, where f is the input image (ie texture image), g is the output image, and h is the filter kernel. The filter selected in the trilinear interpolation algorithm is square, which is a square filtering technique. A typical existing square filtering technique is MIP-MAP (Multiple Texture Mapping) pre-filtering. The main idea of ​​MIP-MAP pre-filtering is to express tex...

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to at least solve one of the above-mentioned technical defects, especially to solve the problem of blurred images caused by oversampling of the anisotropic Feline algorithm in the L+1 layer

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