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  This is a utility routine to perform linear scaling (similar to BYTSCL)
  on image arrays. If differs from BYTSCL only in that a user-specified
  percentage of pixels can be clipped from the image histogram, prior to
  scaling. By default, two percent of the pixels are clipped. Clipping
  occurs at both ends of the image histogram.


    Image Processing


    A byte scaled image is returned.


    image: in, required
      The image to be scaled. Written for 2D images, but arrays of any size are treated alike.
    clip: in, optional, type=float, default=2.0
        The percent of image clipping. Must be value between 0 and 49. Clipping
        occurs from both ends of image histogram, so a clip of 2.0 linearly scales
        approximately 96% of the image histogram. Clipping percents are approximations
        only, and depend entirely on the distribution of pixels in the image. For
        interactive scaling, see cgStretch.


    negative, in, optional, type=boolean, default=0
          If set, the "negative" of the result is returned.
    omax: in, optional, type=byte, default=255
          The output image is scaled between OMIN and OMAX.
    omin: in, optional, type=byte, default=0
          The output image is scaled between OMIN and OMAX.
    threshold: out, optional
        A two-element array containing the image thresholds that were used for the clipping.


      cgLoadCT, 0 ; Gray-scale colors.
      image = cgDemoData(22) ; Load image.
      cgImage, cgClipScl(image, 4)


          David W. Fanning
          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


    Change History::
      Written by: David W. Fanning, 6 September 2007.
      Not sure what this program was doing, but not what I thought. I've reworked
          the algorithm to scale the data appropriately. 25 Oct 2011. DWF.
      Renamed cgClipScl from ClipScl. 27 March 2015. DWF.


    Copyright (c) 2007-2015, Fanning Software Consulting, Inc.

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