Anisotropic filtering

In 3D computer graphics, anisotropic filtering (AF)[1][2] is a technique that improves the appearance of textures, especially on surfaces viewed at sharp angles.

It helps make textures look sharper and more detailed by reducing blur and aliasing that can occur when surfaces are angled away from the viewer.

[3][4] While it requires more processing power than these simpler methods, anisotropic filtering became a standard feature in most graphics cards in the late 1990s[5] and is now commonly used in games and other 3D applications, often with user-adjustable settings.

Anisotropic filtering enhances texture sharpness, counteracting the blur introduced by mipmapping, a common anti-aliasing technique.

That is, when sampling to avoid aliasing on a high-frequency axis, the other texture axes will be similarly downsampled and therefore potentially blurred.

This means that as the degree of anisotropic filtering continues to double there are diminishing returns in terms of visible quality with fewer and fewer rendered pixels affected, and the results become less obvious to the viewer; only a relatively few highly oblique pixels, mostly on more distant geometry, will display visibly sharper textures in the scene with the higher degree of anisotropic filtering.

A video display device can easily contain over two million pixels, and desired application framerates are often upwards of 60 frames per second.