ISIS Application Documentation
Apply histogram equalization to a cube.
Overview
Parameters
Example 1
Description
This program equalizes the histogram of an input cube (defined by FROM), and outputs the results to a file (defined by TO).
By equalizing the input file's histogram, the resulting cumulative distribution becomes linear instead of curved. The following
is an illustration of what happens to an input file. The blue line represents the histogram and the red line is the cumulative
distribution. On the left is the histogram and cumulative distribution of an unmodified image, while the figure on the right shows
how the both the histogram and distribution are altered.
The blue line represents the input file's histogram and the red line represents its cumulative distribution function.
Categories
Applications
History
Sean Crosby 2006-12-15
Original version
Steven Lambright 2008-05-06
Histogram object no longer has SetRange, updated to use SetValidRange
Steven Lambright 2008-05-13
Removed references to CubeInfo
Tyler Wilson 2015-09-03
Commented out a call to Histogram::SetValidRange(min,max)
Because of changes made to the Histogram class.
See Ref. #2188.
Parameter Groups
Files
Name
Description
FROM
Input file to be equalized
TO
Output cube
Histogram Options
Files :
FROM
Description
This file will have its cumulative distribution reshaped to be more linear.
Type
cube
File Mode
input
Filter
*.cub
Files :
TO
Description
The resultant cube containing a linearized image
Type
cube
File Mode
output
Filter
*.cub
Histogram Options :
MINPER
Description
Minimum DN cut-off value at the cumulative percent of the histogram
Type
double
Default
0.5
Minimum
0.0
(inclusive)
Less Than
MAXPER
Histogram Options :
MAXPER
Description
Maximum DN cut-off value at the cumulative percent of the histogram
Type
double
Default
99.5
Maximum
100.0
(inclusive)
Histogram Options :
INCREMENT
Description
Percentage increment for the histogram
Type
integer
Default
1
Minimum
1
(inclusive)
Less Than
MAXPER
Example 1
Histogram equalization
Description
This example shows the results of histogram equalization on a single band of an image.
Command Line
histeq
from=../peaks.cub+6 to=../result.cub
Use histogram equalization to the make the input cube's sixth band distribution function linear.
GUI Screenshot
Histeq Gui
Example Gui
Screenshot of GUI with parameters filled in to perform
a histogram equalization operation with the input image.
Input Images
Input Peaks (band 6) Image
Input image for histeq
Parameter Name:
FROM
This is band 6 of the input image for this example.
Input Peaks (band 6) Image
Band 6 histogram
This is the input image's cumulative distribution for band 6.
Output Images
Output image showing the result of the histogram equalization.
Output image for histogram equalization
Parameter Name:
TO
This is the output image that results.
Output image
Resulting cumulative distribution
This is the output image's cumulative distribution.
