Anisotropic Filtering
From polycount
Anisotropic Filteringis a texture filtering method, specifically for non-square filtering, usually of textures shown in radical perspective (such as a pavement texture as seen from a camera lying on the road).
More generally, anisotropic improves clarity of images with severely unequal aspect ratios. Anisotropic filtering is an improvement of isotropic mip-mapping, but because it must take many samples, it can be very memory intensive.
