How does Image Processing work?
Image processing is actually performed by computing a new value for each pixel in an image. One simple way is to compute a pixel’s value (p’) solely based on its old value (p), without regard to any other pixel. Mathematically, it can be represented by a transformed or mapping function f(), such that,
In this example, f(p) is W-p, where W represents the white colour value. f(p) being applied to an image produces an interval (negative) image. Such individual pixel-based processing of the image is known as pixel-point processing.
By suitably choosing the mapping function, colour correction and alteration, brightness and contrast adjustments can be done on an image. Brightness adjusts the value of each pixel up or down uniformly – increasing brightness makes every pixel lighter while decreasing brightness makes every pixel darker. on the other hand, enhancing contrast makes the lighter pixels even lighter while at the same time making the darker pixels even darker.