CLIPSCL Name
CLIPSCL Purpose
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.
Author
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
Utilities Calling Sequence
scaledImage = CLIPSCL(image, clipPercent)
Arguments
image: The image to be scaled. Written for 2D images, but arrays
of any size are treated alike.
clipPercent: The percent of image clipping. Optional argument is set
to 2 by default. Must be value between 0 and 49. Clipping
occurs from both ends of image histogram, so a clip of 2
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 XSTRETCH.
Input Keywords
NEGATIVE: If set, the "negative" of the result is returned.
OMAX: The output image is scaled between OMIN and OMAX. The
default value is 255.
OMIN: The output image is scaled between OMIN and OMAX. The
default value is 0.
Output Keywords
THRESHOLD: A two-element array containing the image thresholds for clipping.
Return Value
scaledImage: The output, scaled into the range OMIN to OMAX. A byte array.
Common Blocks
None.
Examples
LoadCT, 0 ; Gray-scale colors.
image = cgDemoData(22) ; Load image.
TV, ClipScl(image, 4)
Restrictions
Requires SCALE_VECTOR from the Coyote Library:
http://www.idlcoyote.com/programs/scale_vector.pro
Modification 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.