2D Image Input

The basic two-dimensional image is a monochrome (greyscale) image which has been digitised.

Describe image as a two-dimensional light intensity function f(x,y) where x and y are spatial coordinates and the value of f at any point (x, y) is proportional to the brightness or grey value of the image at that point.

A digitised image is one where

• spatial and greyscale values have been made discrete.
  
• intensity measured across a regularly spaced grid in x and y directions
  
• intensities sampled to 8 bits (256 values).

For computational purposes, we may think of a digital image as a two-dimensional array where x and y index an image point. Each element in the array is called a pixel (picture element). See Figs. 1 and 2.

 

Fig. 1 Greyscale image and highlighted region

  
Figure: Pixel values in highlighted region

 

• 2D Input Devices
  
• Frame Stores