Isis 3 Application Documentation
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Apply a Davinci "Sigma Stretch" (sstretch) to a cube.
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new_dn = (old_dn - avg) * (variance / stddev)Here, avg and stddev stand for the statistical average and standard deviation of all valid pixels in the current pixel's band, respectively. The variance mentioned is not actually the statistical variance of the band, but a user-specified parameter, VARIANCE, that affects how much the histogram of the image is widened.
Name | Description |
---|---|
FROM | Input file to stretch |
TO | Output cube |
Name | Description |
---|---|
VARIANCE | Non-uniformity of the output's histogram |
The input cube which will have the sigma stretch applied.
Type | cube |
---|---|
File Mode | input |
Filter | *.cub |
The resultant cube containing the image after being stretched.
Type | cube |
---|---|
File Mode | output |
Pixel Type | real |
Filter | *.cub |
The nonuniformity of the output image's histogram. For values less than 1.0, the distribution will be closer to uniform. This value must be greater than 0.0.
Type | double |
---|---|
Default | 40.0 |
Minimum | 0.0 (exclusive) |
Two THEMIS Images
Example GUI for I01086005.cub Screenshot of the GUI with parameters set to stretch the first image. |
|
Example GUI for I23851018.cub Screenshot of the GUI with parameters set to stretch the second image. |
Mosaic of the input images for sigmastretch
Parameter Name:
FROM This is a cropped subsection of the mosaic of the input images before being stretched. Note the sharp contrast between the two images when mosaicked. |
Mosaic of the output images for sigmastretch
Parameter Name:
TO This is the same subarea of a mosaic of the output images after being stretched. The contrast is now much more subtle, making the images ready to be blended together along their overlapping areas. |
Travis Addair | 2011-09-08 | Original translation of Davinci's "sstretch" script into Isis 3. |