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| Name | Caption |
|---|---|
| Input Folder | Input directory |
| Output Folder | Output folder |
| Source Channels | Source channels to process |
| Overwrite Results | Overwrite existing results |
| Send Email | Email notification settings |
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Input Folder
Specifies the path to the folder that contains multispectral imagery to which the simulated color will be applied.
This parameter is mandatory.
Output Folder
The path and name of the folder to which to write the output files.
Source Channels
The source channels from the input files to process.
The order of bands in SPOT multispectral images depends on the raw data distribution format. Scenes distributed in the CAP format (available for SPOT1 to SPOT4 only) have G, R, and I bands in channels 1, 2 and 3. Scenes distributed in the DiMAP format (available for all SPOT satellites) have the G, R, and I bands in channels 3, 2 and 1. Because the imported data (or the resulting orthoimage) may have no record of its distribution format, it is necessary that the band ordering be specified explicitly.
This parameter is optional.
Overwrite Results
Select this check box to overwrite the existing output files, if any exist. If this check box is left clear, and an output file exists in the relevant folder, the status of the job displays a message informing you of the existence and name of the output file. The message is also written to the event log of the job.
Send Email
If necessary, you can set up CATALYST Enterprise to send an email notification on job start and job completion.
With this check box selected, an email message is sent to each address specified in the Email Addresses box after the job starts and on completion.
You can specify one or more addresses, and each must be separated by a comma or a semi-colon. The email address of the user currently logged in displays by default.
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Preprocessing requirements
Before running this module, the following requirements must be met to ensure the job processes successfully and produces accurate results:
Module details
The Blue-band Simulation module generates simulated natural-color SPOT and TH-01 satellite images from input multispectral images. It supports multispectral scenes from SPOT and TH-01.
Input files must be in GDB-supported format; both raw and orthorectified images may be processed.
The output images are created by the module, and must not already exist. After processing, each image contains the red and green bands transferred from the input image to channels 1 and 2, and the simulated blue band in channel 3. In addition, all non-raster segments and metadata are transferred from the input image to the output image.
The simulated blue band is created according to the algorithm in the paper by Patra et al. (2006) noted in the 'References' section. The blue band (B) is created as a linear combination of the three input bands as follows:
B = a + bG + cR + dI
If any of the three input G, R, and I values is zero at a pixel, all output values at the pixel (R, G, B) are set to zero. If no valid (non-zero) pixels exist in the output image, a warning is issues. In this case, all pixels in all bands are treated as NO_DATA (0).
The Histogram Trim Percentage parameter optionally specifies the percentage trim of pixel values in the output image. If specified, the values must be in the range [0, 49.99]. If unspecified, the green and red band data is transferred unchanged from the input image, and the simulated blue band values are truncated to the range [1, 255]. Specifying one value for this parameter results in a symmetric histogram trim of all output channels; two specified values result in a non-symmetric histogram trim.
In histogram trim, the counts in histogram bins at either tail of the histogram are accumulated while moving towards the histogram center. The process continues until the accumulated value exceeds the specified percentage of all image pixels. The last pixel value not exceeding the specified value becomes the value used in the linear stretch of the output values. The trimmed values are set to the extreme output value, either 1 or 255.
The final output images will have realistic colors, with vegetation green, urban areas gray, water blue, and bare earth tan to brown. The colors may be further adjusted by manually creating and editing color lookup tables (LUTs).
Job results
For each scene found in the specified input folder, this module produces a simulated natural color image in PCIDSK format. Each output image contains the Red and Green bands transferred from the input image to channels 1 and 2, and the simulated Blue band in channel 3. In addition, all non-raster segments and metadata are transferred from the input image to the output image.
<SCENE_ID>_RAW_RGB.pix
Output images are located in the folder specified in the Output Folder parameter.
You can now open the ingested scenes in CATALYST Professional Focus or OrthoEngine to perform quality assurance tasks, or proceed to the next module.
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Patra, S.K., M. Shekher, S.S. Solanki, R. Ramachandran and R. Krishnan, (2006). "A technique for generating natural colour images from false colour composite images." International Journal of Remote Sensing, 27(14): 2977-2989.
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