ISIS Application Documentation
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Compare two cubes for differences
This program compares two cube files pixel by pixel, with results written to the log and/or user specified output file.
|Compare||The files are different if any pair of pixels is different, otherwise the files are identical.|
|Sample||The sample of the first pair of pixels that is different|
|Line||The line of the first pair of pixels that is different|
|Band||The band of the first pair of pixels that is different|
|AverageDifference||The average absolute value of the differences of all pairs of pixels|
|StandardDeviation||The standard deviation of the absolute value of the differences of all pairs of pixels|
|Variance||The variance of the absolute value of the differences of all pairs of pixels|
|MinimumDifference||The smallest absolute value of the differences of all pairs of pixels|
|MaximumDifference||The largest absolute value of the differences of all pairs of pixels|
|MaxDifferenceSample||The sample of the pair of pixels with the largest difference|
|MaxDifferenceLine||The line of the pair of pixels with the largest difference|
|MaxDifferenceBand||The band of the pair of pixels with the largest difference|
|ValidPixelDifferences||The number of pairs of nonspecial pixels that are different|
|SpecialPixelDifferences||The number of pairs of pixels that are different where at least one pixel is special|
|SigFigAccuracy||The minimum value of the approximate number of significant figures of the differences of all pairs of pixels. The approximation is given by floor(log10(in1)) - floor(log10(abs(in1 - in2)) where in1 and in2 are the pair of pixels.|
|SigFigMaxDifferenceSample||The sample of the first pair of pixels where SigFigAccuracy in minimized|
|SigFigMaxDifferenceLine||The line of the first pair of pixels where SigFigAccuracy in minimized|
|SigFigMaxDifferenceBand||The band of the first pair of pixels where SigFigAccuracy in minimized|
|FROM||First cube for comparison|
|FROM2||Second cube for comparison|
|OUTPUTDIFFS||Output table of differences|
|PRECISION||The decimal precision of the output values|
|COUNT||Number of differences to be displayed|
The file specification for the first input cube. This cube will be compared to the cube given in "FROM2".
The file specification for the second input cube. This cube will be compared to the cube given in "FROM".
A text file in label format which will contain the results of this compare. This file can be used in conjunction with the "getkey" program to pass the results to another program.
This parameter allows a tolerance when comparing values. If the difference between pixel values is less than or equal to TOLERANCE,the values are considered to be equal. The default value, DBL_EPSILON, is machine specific, but a possible value is 2.2204460492503131e-16. It is defined in float.h.
This determines if the differences will be output to a table. If it is checked, the options below will be opened up and used to determine the specifics of the table to which the data will be written. The differences are written out as a table, where the columns represent the sample number, once for each image, and the rows represent the line number, with the data being the DN at that point.
This number determines how many digits past the decimal point will be displayed for the compared values in the output table.
This indicates the number of differences to be displayed. The count is made from left to right, top to bottom. Differences on the top row are considered first, then the second row, and so on.
Screenshot of GUI with parameters filled in to perform the compare operation
First input image for compare
This is the first input image for the compare example.
Second input image for compare
This is the second input image for the compare example.
The output log
This is the default output compare log. Use the TO parameter for a text file output.
|Tracie Sucharski||2002-10-10||Original version|
|Tracie Sucharski||2002-11-12||Add user parameter, IGNORESPECIAL, which indicates whether special pixel values in either file are ignored in the comparison.|
|K Teal Thompson||2002-11-25||Add example.|
|K Teal Thompson||2003-04-11||Make images smaller|
|Stuart Sides||2003-04-29||Added the band number to the logged information|
|Stuart Sides||2003-05-01||Fixed multipal run bug where once the inputs were reported as different any files entered after that would aldo be reported as different.|
|Stuart Sides||2003-05-16||Modified schema location from astogeology... to isis.astrogeology...|
|Stuart Sides||2003-07-29||Modified filename parameters to be cube parameters where necessary|
|Jeff Anderson||2003-08-26||Changed default extension handling mechanism|
|Stuart Sides||2003-11-07||Modified results pvl to not include the results group|
|Jacob Danton||2006-04-07||Changed the IGNORESPECIAL from a string to a bool.|
|Elizabeth Miller||2006-05-19||Modified to output statistical data about the differences|
|Elizabeth Miller||2006-06-15||Added ValidPixelDifferences to output|
|Brendan George||2006-09-28||Documentation fixes|
|Tracie Sucharski||2007-02-26||Documentation correction-Description said program exited at first difference. This is no longer the case, all pixels are compared and statistics are collected.|
|Brendan George||2007-04-25||Added tabular output option. Option allows the program to collect and print out a table of the differences found|
|Brendan George||2007-04-26||Changed name from compare to cubediff|
|Steven Lambright||2007-06-08||Fixed problems with the special pixel comparisons: changed IGNORESPECIAL to only ignore the case where one pixel has a DN value and the other pixel is special, fixed a problem where the special pixel difference would never be the first difference, fixed a comparison of DN value differences before checking if the pixel is special. Added significant figure reports for testing purposes.|
|Steven Lambright||2007-06-11||Removed IGNORESPECIAL|
|Steven Lambright||2007-06-12||Updated example images|
|Steven Lambright||2007-06-18||Fixed bug where sig. fig. accuracy would report "1" when it should report "0"|
|Brendan George||2007-08-09||Integrated WriteTabular and Column (tabular output objects) as application-specific classes|
|Steven Koechle||2009-05-14||Changed output, if no valid pixel differences, output zero instead of NULL8|
|Sharmila Prasad||2010-02-26||Incuded keywords MaxDifference Line, Sample and Band in the output to indicate the line, sample, band where the max cube difference occured|
|Jeffrey Covington||2015-01-09||Added descriptions for each label of the output|
|Jeffrey Covington||2015-01-13||Fixed output when run multiple times in the GUI|