Version 1.0, August 31, 2001, Copyright, Hugh Jack 1993-2001

14.6 IMAGE PREPROCESSING

 

· Images are basically a set of pixels that are often less than a perfect image representation. By preprocessing, some unwanted variations/noise can be reduced, and desired features enhanced.

 

· Some sources of image variation/noise,

  1. - electronic noise - this can be reduced by designing for a higher Signal to Noise Ratio (SNR).
  2. - lighting variations cause inconsistent lighting across an image.
  3. - equipment defects - these cause artifacts that are always present, such as stripes, or pixels stuck off or on.