Suppose that a continuous image is approximated by equally spaced samples arranged in the form of an array as:
Each element of the array refered to as "pixel" is a discrete quantity. The array represents a digital image. The above digitization requires a decision to be made on a value for N a well as on the number of discrete gray levels allowed for each pixel.
It is common practice in digital image processing to
let N=2n and G = number of gray levels
It is assumed that discrete levels are equally spaced between 0 to L in the gray scale.
Therefore the number of bits required to store a digitized image of size N x N is b = N x N x m .
find the number of bits required to store a 2048x2048 image with 256 gray levels
128 x 128 image with 256 gray levels (ie 8 bits/pixel) required a storage of ~ 17000 bytes.
128 x 128 x 8 = 131072 bits = 131072 x 0.125 = 16384 i.s closer to 17000 bytes