4802-2-2: Point Processes II

Weblinks gathered by Greg Matthews

Summary

This lecture focused on several types of point processes for digital image processing.

Contrast Stretching

Contrast stretching is a type of histogram equalization. It is used to increase the contrast in an image. The values in the histogram are stretched across the whole specturm of the histogram without losing intensity. This causes the image to have higher constrast. The folling are several links on contrast stretching:

• http://geog.hkbu.edu.hk/virtuallabs/rs/env_contrast.htm presents information on contrast stretching. [5]
• http://www.incx.nec.co.jp/imap-vision/library/wouter/contrast_stretch.html basic information on contrast stretcing with sample code. [3]
• http://www.ph.tn.tudelft.nl/Courses/FIP/noframes/fip-istogram.html provides equations for contrast stretching. [3]
• http://tutorial.core.ipp.pt/mirrors/Tutorial/Sect1/nicktutor_1-12.html describes contrast stretching and spacial filtering. [5]

Adaptive Contrast Enhancement

This filter is another type of histogram equalizaiont. The filter is adaptive and has the ability to change its behaviors with the image by acting like an area process. The follow links discuss adaptive contrast enhancement:

• http://www.im.lcs.mit.edu/broch/cam1.html describes how cameras use this filter. [3]
• http://www.mdag.org/users/stark/improc/case/index.html does a good job at describing how ACE works. [4]
• http://www.cevis.uni-bremen.de/MeVis/projects/thorax/radiography/chest.html shows how chest radiography uses ACE. [3]
• http://ipe.et.uni-magdeburg.de/~hamid/enhance.htm fuzzy image processing. [4]

Histogram Equalization

This filter takes a histogram and makes each shade have and equal amount of intensity throughout the image. The following links discuss histogram equalization:

• http://web.singnet.com.sg/~chheng/histeq.htm describes histogram equalization and shows an example.[3]

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