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ISIS Application Documentation

histitch

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Merge a HiRISE channel pair to make a single image

Description
Categories
Groups
Examples
History

Description

The program allows the user to combine two HiRISE channels to form a single CCD image. Histitch will typically be run after radiometric correction and prior to geometric processing. The two input files must be the individual channel files (channels 0 and 1) of the same CCD observation. The program will test to make sure the Observation IDs and CCD IDs of the input cubes match, and that one cube is channel 0 and the other is channel 1. The program is clever enough to figure out the channels associated with each input file and correctly order them in the output file. Any ancillary data "blobs" will not be propagated to the output file. The channel number on the output cube is set to 2 to signify that it is the combination of channels 0 and 1.

histitch can create a CCD image if when only one channel is provided. The proper placement, left half of CCD for channel 1 images, right half for channel 0, is determined from the input file and the remainder of the CCD is filled with Nulls.

Categories

Parameter Groups

Files

Name Description
FROM1 First HiRISE Channel file.
FROM2 Second HiRISE Channel file.
TO Output HiRISE CCD image.

Balance Channels

Name Description
BALANCEOption to balance channel 0 and channel 1
SKIP Number of Pixels to skip on the edges of the image.
SEAMSIZE Number of Pixels on the seam
WIDTHWidth of filter to apply to line averages
FILL Apply spline interpolation to channel line averages
CHANNELSpecify channel to normalize to (hold as truth)
OPERATOROption to balance channel 0 and channel 1

Files: FROM1

Description

This is the first of a pair of input HiRISE channel image files. This file can be either the channel 0 or 1 file. The pair of input files must correspond to the the same observation of a HiRISE CCD.

Type cube
File Mode input
Filter *.cub

Files: FROM2

Description

This is the second of a pair of input HiRISE channel image files. This file can be either the channel 0 or 1 file. The pair of input files must correspond to the the same observation of a HiRISE CCD.

If the user does not provide a file for the second file, histitch will create a full CCD and map the FROM1 file into the proper location in the CCD. This allows creation of the full CCD without both channels being required.

Type cube
File Mode input
Internal Default None
Filter *.cub

Files: TO

Description

The output cube is a HiRISE CCD image with the two channel files combined. The channel number for this cube is set to 2.

Type cube
File Mode output
Filter *.cub

Balance Channels: BALANCE

Description

A feature which calculates the average on each channel and multiplies one side with the ratio of the averages

Type string
Default FALSE
Option List:
Option Brief Description
TRUEBalance On Enables balance feature.

Exclusions

  • WIDTH
  • FILL
  • OPERATOR
FALSEBalance Off Disables balance feature.

Exclusions

  • SEAMSIZE
  • SKIP
  • WIDTH
  • FILL
  • CHANNEL
  • OPERATOR
EQUALIZELine-by-line equalization

Enables line-by-line equalization feature. This feature uses the SEAMSIZE and SKIP parameters to generate an average of each line for both channels. These averages can be filtered (using an LPF) and missing data filled (using spline interpolation). The results can be subtracted or multiplied to correct for downtrack differences in the channels.

When this option is selected, an ISIS Table is created called HistitchStats. This table contains four fields: Channel1Original, Channel0Original, Channe1Correction, and Channel0Correction. If the MULTIPLY OPERATOR is selected, then one channel corrected column will be all 1.0. For the ADD OPERATOR one column will contain all 0.0.

The two original columns will contain the results of averaging the specified window with the values of SEAMSIZE and SKIP parameters. The correction columns will contain the ratio (MULTIPLY) or additive (ADD) component of the correction that was appled to channel 0 or 1, whichever one is not designated the hold channel in the CHANNEL parameter.

The ISIS program tabledump can be used to extract the contents of this table to an ASCII file.

Inclusions

  • SEAMSIZE
  • SKIP
  • WIDTH
  • FILL
  • CHANNEL
  • OPERATOR

Balance Channels: SKIP

Description

Number of pixels to skip on each side of the seam before the program starts to accumulate pixel DN's to calculate the seam average value.

Type integer
Default 7
Minimum 0 (inclusive)

Balance Channels: SEAMSIZE

Description

Number of pixels (after skipping 'SKIP' number of pixels) used to compute the averages on each side of the seam.

Type integer
Default 11
Minimum 1 (inclusive)

Balance Channels: WIDTH

Description

Specify the width of the filter to apply to both channel line averages. This is turned off with a value of 0.

Type integer
Default 0

Balance Channels: FILL

Description

Apply a spline interpolation to each line average to fill any gaps that may exist

Type boolean
Default true

Balance Channels: CHANNEL

Description

Typically, channel 1, the left channel, is held and channel 0, the right channel, is corrected. This option allows the user to select which channel to hold.

Type integer
Default 1
Minimum 0 (inclusive)
Maximum 1 (inclusive)

Balance Channels: OPERATOR

Description

A feature which calculates the average on each channel and multiplies one side with the ratio of the averages

Type string
Default MULTIPLY
Option List:
Option Brief Description
MULTIPLYMultiply channel line average corrections Line average ratio is multiplied to the specified channel to equalize the combined CCD channels.
ADDAdd channel line average corrections Line average ratio is added to the specified channel to equalize the combined CCD channels.

Examples

Example 1

HiRISE image

Description

This example shows the hiStitch application.

Command Line

histitch from1=IN/Channel0.cub from2=IN/Channel1.cub to=OUT/output.cub balance=true skip=7 seamsize=11
hiStitch gui example

GUI Screenshot

hiStitch Gui

Example Gui

Screenshot of GUI with parameters filled in to perform a hiStitch operation on the input images.

Input Image

Input HiRISE images

Input images for hiStitch

Parameter Name: FROM1,FROM2

These are input images stitched together without the balance option on.

Output Image

Output image showing results of the hiStitch application.

Output image for hiStitch

Parameter Name: TO

This is the output image with the balance option TRUE.

History

Eric Eliason2004-07-31 Original version
Elizabeth Ribelin2005-02-22 Added obsevation id, ccd id, and channel number tests
Kris Becker2006-02-22 Made FROM2 optional and allow creation of full CCD with just one channel file.
Brendan George2006-08-24 Added StitchedChannels keyword to Instrument Group, to identify which channels were used.
Brendan George2006-09-01 Added StitchedProductIds keyword to Instrument group, to identify which images were used.
Brendan George2006-09-28 Documentation fixes
Stacy Alley2007-08-16 Added the balance option.
Steven Lambright2008-05-13 Removed references to CubeInfo
Kris Becker2008-10-02 Added new EQUALIZE balance option that has utilizes new options WIDTH, FILL, CHANNEL and OPERATOR parameters. This new option applies a line-by-line equalization of the CCD channels using and addative or multiplicative option.
Jeannie Walldren2008-11-05 Replaced references to DataInterp class with NumericalApproximation.
Kris Becker2008-12-08 Set channel 1 (left) as the default to hold instead of channel 0. Added reporting of results to label in the Histitch group. Also added creation of a Table of data when the EQUALIZE BALANCE option is selected.
Kris Becker2008-12-23 The BALANCE=TRUE option now honors the CHANNEL parameter and applies the coefficient/ratio to the other channel.
Steven Lambright & Stacy Alley2009-06-09 Added error checking to SKIP and SEAMSIZE parameters. Fixed problem with accessing out of array bounds.