hidestripe

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.

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

Description

This image will have the hidestripe correction applied to it.

Type	cube
File Mode	output
Filter	*.cub

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 ADD Additive 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. MULTIPLY Multiplicative 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.

Description

Type	string
Default	AUTO
Option List:	Option Brief Description AUTO Automatically determine what parity to correct EVEN Apply correction to even lines (2,4,6 ...) ODD Apply correct to odd lines (1,3,5 ...)

This example shows the default additive correction applied to a binned 0 image in an image that is mixed and includes binning modes 0 and 1

hidestripe from=HiRISE/cubs/PSP_RED5_bin0.cub to=HIRISE/cubs/PSP_RED5_bin0_corrected.cub

Default Gui

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

Before correction

Input image before hidestripe Parameter Name: FROM The image before the correction is applied. Note the stripes.

After correction

Output image after hidestripe Parameter Name: TO The same image has now been smoothed such that the stripes are removed.