ISIS 3 Application Documentation
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Computes a transformation to shift entire lines or samples
Overview | Parameters |
Parameter GroupsFiles
Spline parameters
Interpolation
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Use this parameter to select the filename. All bands within the file will be slithered unless a specific band is specified.
Type | cube |
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File Mode | input |
Filter | *.cub |
This file will contain the results of the slither transform
Type | cube |
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File Mode | output |
This file will contain the control net used to compute the translation. It will typically come from the coreg or hijitreg application but could come from other sources.
There are some restrictions/requirements as to the content and form of this file. First, there must only be two measures per control point. If there are any more or less than two they are silently ignored. This will typically result in failure as each interpolation option requires a minimum number of points. (If one point does not satisfy this requirement, typically none of them will and slither will terminate with an error indicating not enough points.)
Secondly, one of the measures should be identified as the reference image. The reference image is typically the image that was provided in the MATCH parameter to coreg or hijitreg. If this is not the case, slither assumes the first point is the reference image. It has no other way to determine this.
This is important because of the way control points are combined into a single column at each row. Typically, applications such as coreg and hijitreg will compute coregistration chips at the same line for each column. The line numbers are used to determine which columns are combined for each row. If the correct lines cannot be determined (with robust equvialence checking considering roundoff), then chances are good that the translation will not work properly. For example, if the reference image was erroneously selected to be the FROM parameter from the registration applications, then it would compare translated (shifted) lines and conclude that every chip is a unique row. This would result in as many rows as chips and, by definition, this would cause the interpolation to fail.
Unfortunately, this is mostly programmer controlled so when these types of problems occur, they should be reported to the Isis Support.
Type | filename |
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Filter | *.net |
This file is optional and if specifed, will contain a dump of the determination of the collapse of the columns at each row and the statistics at each row. It also contains the absolute line and sample mapping for each line and (center) sample of each line as well as relative line and sample offsets at each line.
Type | filename |
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Internal Default | None |
Filter | *.txt |
slither provides 4 different (spline) interpolation options. The interpolation option chosen is used to compute a continuous (or piecewise continous) interpolation so that each line and sample has a transform location that maps the output line and sample to a shifted input line and sample. These interpolations provide this mapping.
Type | string | |||||||||||||||
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Default | CUBIC | |||||||||||||||
Option List: |
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This parameter provides the ability to apply the transform to either the FROM or MATCH images used to compute the control net correlation. FORWARD is used for the FROM image and REVERSE is when the MATCH, or the reference, image is provided in the FROM parameter to slither.
Type | string | |||||||||
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Default | FORWARD | |||||||||
Option List: |
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In some cases, an initial offset was added to start the image registration. This parameter allows for this shift to be applied to the transform. This is also equivalent to the Isis translate transform application that shifts the image spatially.
Negative values shifts the image down. Positive values shifts the image up.
Type | double |
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Default | 0.0 |
In some cases, an initial offset was added to start the image registration. This parameter allows for this shift to be applied to the transform. This is also equivalent to the Isis translate transform application that shifts the image spatially.
Note that negative values shift the image to the right. Positive values shift the image left.
Type | double |
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Default | 0.0 |
This is the type of interpolation to be performed on the input.
Type | string | ||||||||||||
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Default | CUBICCONVOLUTION | ||||||||||||
Option List: |
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