Bilinear filtering is one

method in

computer graphics for making

pixels look

smoother when

drawing to the

screen. (Another is

bicubic filtering, which looks much nicer, and will be discussed later).

So to kick this off, a bilinear

graph looks like this:

/|\

/ | \

/ | \

/ | \

/ | \

/ | \

/ | \

-------------

Now take the

origin as the

pixel whose color is to be

calculated. The theory goes is that each pixel directly next to that one factors in

heavily, and, up to a certain threshold, each pixel after that factors in

inversly proportional to its

distance from the pixel in question. Obviously the pixels original color factors in the greatest when determining the final

color. Most filtering

algorithms have to make a

second pass at the entire pixel table to do this sort of filtering, although some really great implementations use some a lot of numbers and some scary

math to accomplish it in one pass.

Bilinear filtering is an

additive filter applied to the pixel grid, while Bicubic is subtractive. The only problem is that this method of graphical filtering tends to look a little fuzzy when all is said and done. Because of this woe, the slightly more complicated bicubic filtering was developed, whereby pixels at the end sharpen picture by

subtracting from the final color.