•        An image may be defined as a two dimensional function f(x,y) where x and y are spatial coordinates and amplitude of f at any pair of coordinates (x,y) is called the intensity  or Graylevel of the image at that point.
Digital Image:
•         A digital Image is composed of a finite number of elements each of which has a particular location and value.
•        These elements are referred to as Picture Elements, Image Elements, Pels or Pixels.

Power Law?
a power law is a functional relationship between two quantities, where one quantity varies as a power of another
1.  Contrast stretching
Contrast stretching (often called normalization) is a simple image enhancement technique that attempts to improve the contrast in an image by `stretching' the range of intensity values it contains to span a desired range of values, e.g. the the full range of pixel values that the image type concerned allows.
1.  Gabor filter
In image processing, a Gabor filter, named after Dennis Gabor, is a linear filter used for edge detection. Frequency and orientation representations of Gabor filters are similar to those of the human visual system, and they have been found to be particularly appropriate for texture representation and discrimination.
Image acquisition


1.     Digital imaging or digital image acquisition is the creation of digitalimages, typically from a physical scene. The term is often assumed to imply or include the processing, compression, storage, printing, and display of such images.