Digital Image
Introduction:
Representation of a 2-Dimensional image or scene as a finite set of digital values is an Digital Image.
It is the digital representation of a real scene or approximation of a real scene also known as digitization.
These digital values are called as pixel values.
Pixel values usually represent gray levels, colours, opacities, etc.
Some common image formats are:
- 1 sample per point or single value per point/pixel : black&white or grayscale image (e.g. [1] or [0] for binary image & [0] to [255] for grayscale image).
- 3 samples per point or three values per point/pixel : Red, Green, and Blue(RGB) image (e.g. [0,22,100] where red→0, green→22 & blue→100).
- 4 samples per point or four values per point/pixel : Red, Green, Blue, and Alpha image, where alpha attribute is used for opacity.(e.g. [10,22,100,0] where red→10, green→22, blue→100 & alpha→ 0).
Here, the values inside square brackets are the intensity levels of image and 0/1 alpha value represent its opacity.
Digital image representation:
Digital image is simply represented as a 2-dimensional arrangement of pixel intensity values and can be defined as function f(x,y) where x,y are the spatial coordinates representing the position of pixel intensity values as shown in following diagram.
