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hifurrows

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Null furrowed pixels

Overview Parameters

Description

The original version of the program works by finding the correlation between the columns in an input image. With a Channel 0 image, the first five columns are examined; in a Channel 1 image, the last five columns are examined (Channel 2 images are not supported).

If the statistical results suggest a furrow is detected (i.e. the correlation between two columns is below a certain threshold), then the affected column is replaced with Null pixels. If an input image does not have a furrow, none of its pixels will be altered. The label of all output files will include a new group called "Correlations." This group lists the correlations between the relevant columns. For example, "Column3to2 0.987..." means there is a strong positive correlation between columns 2 and 3 (and very unlikely to have a furrow in the area).

For the newer version, the processing has been taken from the Version 1.42 of the original HiCal pipeline perl script and processes images with summing modes 2 and 4 only.

Furrows are checked only in the columns which are based on Channel and the Summing mode. Each specified column will have a Threshold DN based on the Summing mode and CcdId. Then the starting sample and number of samples in the specified columns are determined based on the Summing mode and Channel. The DN value of pixels in these samples are checked to be in the 0 and respective Threshold range. If not, they are determined to be a furrow and set to NULL. If a furrow was found, then trimfilter and lowpass(if option is set) are run on the image in a pipeline to smooth the edges which were Nulled due to the furrows.

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History

Sean Crosby2007-04-03 Original version
Steven Lambright2008-05-12 Removed references to CubeInfo
Sharmila Prasad2011-09-02 Added newer version of implementing hifurrows taken from the Version 1.42 of the original HiCal pipeline perl script.

Parameter Groups

Files

Name Description
FROM Input file
TO Output cube
NEW_VERSIONUpdated furrows functionality from the hical pipeline

Furrow parameters

Name Description
CORRELATIONCorrelation threshold

Options

Name Description
LOWPASSRun Lowpass filter if Furrows are found
X

Files: FROM


Description

The cube to be corrected

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

Files: TO


Description

The resultant cube containing the modified data.

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

Files: NEW_VERSION


Description

This option uses the updated furrows functionality from the hical pipeline script version1.42

Type boolean
Default FALSE
Exclusions
  • CORRELATION
Inclusions
  • LOWPASS
Close Window
X

Furrow parameters: CORRELATION


Description

The maximum correlation from pixel to pixel. If the correlation between two pixels suddenly drops below this value, then a furrow has been detected.

Type double
Default 0.75
Minimum 0.0 (inclusive)
Exclusions
  • LOWPASS
Close Window
X

Options: LOWPASS


Description

Run Lowpass filter if Furrows are found

Type boolean
Default true
Close Window