Name

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      HistoMatch

Purpose

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      This is a function for Histogram Matching, in which an image
      is manipulated in such a way that it's final histogram approximates
      the histogram of an input image or histogram. Histogram matching
      allows the user to specify the shape of the histogram of the final
      product.

Author

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      FANNING SOFTWARE CONSULTING
      David Fanning, Ph.D.
      1645 Sheely Drive
      Fort Collins, CO 80526 USA
      Phone: 970-221-0438
      E-mail: david@idlcoyote.com
      Coyote's Guide to IDL Programming: http://www.idlcoyote.com

Category

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      Image Processing

Calling Sequence

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      output_image = HistoMatch(image, histogram_to_match)

Inputs

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      image - The input image to be manipulated. Assumed to be a 2D byte array.
      histogram_to_match - Can be either a 1D long vector of 256 elements specifying
          the histogram to match, or a 2D byte array from which the histogram to
          match is calculated.

Outputs

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      output_image - The manipulated image adjusted to the histogram specifications.

Input Keywords

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      None.

Output Keywords

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      None.

Dependencies

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      None.

Method

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      Based on the Histogram Matching method on pages 94-102 of Digital
      Image Processing, 2nd Edition, Rafael C. Gonzalez and Richard E. Woods,
      ISBN 0-20-118075-8.

Example

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      There is an example program at the end of this file. It will require cgImage
      from the Coyote Library to run. You can also find an explanation of this program
      at http://www.idlcoyote.com/ip_tips/histomatch.html.

Modification History

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      Written by David W. Fanning, January 2003.