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ISIS 3 Application Documentation


hidestripe

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Corrects a known striping pattern in HiRISE images.

Overview Parameters Example 1

Description

In mixed mode HiRISE images, there is a tendency for every other line in the ccd with the lower binning mode to be significantly darker or lighter than normal image data would suggest. This program attempts to correct that problem. 2 passes through a cube are necessary to perform the correction. The first pass gathers information on each line of the cube to determine if the striping phenomenon occurs in odd numbered lines or in even numbered lines, and also gathers information to perform the actual correction.

The second pass through the data performs the actual correction, of which there are two different types. The default, an additive correction, is of the following form for each pixel
    					     
                                         ((Line[i-1]) + Line[i+1])
                Pixel[i,j] - Line[i] +   --------------------------
                                                      2
    
The other correction, a multiplicative correction of a similar style, is of the form
                Pixel        ((Line[i-1]) + Line[i+1])
               -------   *  ---------------------------
               Line[i]                    2
    

It should finally be noted that the striping pattern has been observed to be most prevalent in a certain quardrant of the image, though that phase is not the same for all images. In order to address this irregularitiy, the line averages shown above are not for the entire line, but only for the quarter of the line in which sample i exists.

Caution should be taken when running hidestripe: it should only be run on images where different CCDs are run at different binning modes. Of those, only channels that are not used in the highest binning mode of the image should be corrected. For example, if an image has binning modes 1, 2, and 4 the CCDs with modes 1 and 2 may be hidestripe'd, but in an image that is only binned in modes 1 and 2, the bin 1 CCDs are the only ones that need the hidestripe correction.


Categories


History

Drew Davidson2006-05-30 Original version
Drew Davidson2006-07-29 Changed to calculate phase limits differently for Channel 1
Drew Davidson2006-08-17 Added capability to process bin 2 data
Drew Davidson2007-01-05 Allowed users to specify odd or even correction
Steven Lambright2008-05-13 Removed references to CubeInfo
Sharmila Prasad2010-12-21 Destripe for images with summing greater than 2

Parameter Groups

Files

Name Description
FROM Single hirise channel in cub form
TO Output cube to contain cub with correction.

Correction Type

Name Description
CORRECTIONType of correction to apply

Correction Start

Name Description
PARITYSpecify line stripes as an even or odd pattern
X

Files: FROM


Description

input channel file. The file must have a number of samples divisible by four so that it may be equally divided into phases. Also, the image should exibit the horizontal striping problem addressed above. Otherwise, this program will do an unwanted normalization.

Type cube
File Mode input
Filter *.cub
Close Window
X

Files: TO


Description

This image will have the hidestripe correction applied to it.

Type cube
File Mode output
Filter *.cub
Close Window
X

Correction Type: CORRECTION


Description

A correction that is either multiplicative or additive in nature. For more specific information on the nature of the correction, see the general program description

Type string
Default ADD
Option List:
Option Brief Description
ADDAdditive correction Correct by subtracting the average of the line needing correction from every pixel on that line and then adding the average of the line above and below that line.
MULTIPLYMultiplicative correction Correct by dividing the average of the line needing correction from every pixel on that line and then multiplying the average of the line above and below that line.
Close Window
X

Correction Start: PARITY


Description

Type string
Default AUTO
Option List:
Option Brief Description
AUTOAutomatically determine what parity to correct
EVENApply correction to even lines (2,4,6 ...)
ODDApply correct to odd lines (1,3,5 ...)
Close Window

Example 1

Additive correction

Description

This example shows the default additive correction applied to a binned 1 image in an image that is mixed and includes binning modes 1 and 4

Command Line

hidestripe from=HiRISE/cubs/RED5_bin1.cub to=HIRISE/cubs/RED5_bin1_corrected.cub
Note that the defaults are not changed, and thus the additive correction is applied.

GUI Screenshot

Default Gui

Example Gui

Parameters set to perform additive correction. No options have been changed from their defaults (though required TO/FROM have).

Input Image

Before correction

Input image before hidestripe

Parameter Name: FROM

The image before the correction is applied. Note the horizontal stripes.

Output Image

After correction

Output image after hidestripe

Parameter Name: TO

The same image has now been smoothed such that the horizontal stripes are removed.