| Back to top |
| Back to top |
| Name | Caption |
|---|---|
| Input Orthos | Input orthorectified scenes |
| Output Folder | Output directory |
| Output File Type | Output file type |
| Output File Options | Output file options |
| Overwrite Results | Overwrite existing results |
| Send Email | Email notification settings |
| Source Background Type | Source background type |
| Source Background Value | Source background pixel value |
| Lower Cloud Reflectance Threshold | Lower cloud reflectance threshold (haze band) |
| Upper Cloud Reflectance Threshold | Upper cloud reflectance threshold (haze band) |
| Water Threshold | Upper water reflectance thresholds (NIR, SWIR) |
| Cloud Dilation | Cloud dilation factor |
| Calibration File | Text file of calibration coefficients |
| Remove Small Clouds | Whether to remove small clouds |
| Minimum Size | Clouds smaller than the minimum size will be removed |
| Unit | Unit for minimum size |
| Smooth Cloud Polygons | Generate smooth cloud polygons |
| Remove Haze | Remove haze from output image |
| Haze Coverage | Percentage of pixels covered by haze |
| Back to top |
Input Orthos
Specifies the path of the folder containing orthorectified satellite scenes to be atmospherically corrected.
Input scenes must follow the standard PCI naming convention; that is, supported file names end with "ORTHO_MS.PIX".
This parameter is mandatory. See Details for more information.
Output Folder
The path of the output folder to which to write the coarse classification masks, and the haze-corrected (HZC) images.
This parameter is mandatory.
Output File Type
The format of the output file.
For more information on the supported file formats, see GDB-supported file formats.
Output File Options
The options to apply when creating the output file or files. The available options are specific to the file format; in each case, the default of no options is allowed.
For more information on the options available for the output file type you specify, see GDB-supported file formats.
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.
Source Background Type
The method to use to determine which pixels in the source image to process as background (NoData) pixels. In general, if a pixel is considered NoData, the module processes it in a specific manner.
If the Any option or the All option is selected, a value must be specified for the Source Background Value parameter.
File Metadata, else None: reads the NoData value from the input-file metadata. The module first checks for the file-level metadata tag NO_DATA_VALUE in the source raster. If the tag is present, this value is used as a default for all channels in the file. Next, the module checks for channel-level NoData tags; if one is found, the channel-level value overrides the file-level value for that channel.
If there are channel-level NoData tags, but no file-level tag, a pixel is considered as NoData if each of the channels with a NoData tag corresponds to its NoData value. In this case, channels without a NoData tag are ignored when identifying background pixels.
If the file does not contain NoData tags, all pixels in the source image are considered valid.
For specific examples, see the Source Background Value parameter description.
Source Background Value
The source background value is provided as either a single number (applied to all channels) or as a pixel "stack" (a comma-delimited list of values). If a pixel stack is provided, but the number of values does not equal the number of channels, the list is truncated or the last value is repeated as necessary. The background values provided is truncated to the range allowed by the source image data type.
Source Background Type set to All and Source Background Value set to 0: a pixel is considered background if all three channels are zero.
Lower Cloud Reflectance Threshold
Optionally specifies, in percentage (1-100), the lower empirical threshold (bound) used to identify the minimum TOA (Top of Atmosphere) reflectance value in the blue or green haze band used to determine the seeds of clouds (the central part of the clouds).
Upper Cloud Reflectance Threshold
Optionally specifies, in percentage (1-100), the minimum Top of the Atmosphere reflectance (in percentage) in the blue (or green) band, but it is used to capture the area of the cloud not captured by the lower threshold (the extension of the cloud). This value must be higher than that specified for the Lower Cloud Reflectance Threshold.
Water Threshold
Specifies, in percentage, the upper reflectance threshold used to identify water pixels in the atmosphere.
Water Threshold = NIR_THRESH, SWIR_THRESH
If this parameter is not specified, a default value of 5 is used for the NIR band and a default value of 3 is used for the SWIR band (when applicable).
Cloud Dilation
Optionally specifies the amount, in pixels, by which to dilate, or expand, the cloud so that the 'halo' effect in the cloud is eliminated (that is, covered by the cloud mask).
If this parameter set to 0, no dilation occurs. If this parameter is not specified, the default cloud dilation factor is 2 pixels. The maximum dilation factor is 200 pixels.
Calibration File
The path and file name of the text file that contains, for each band, the calibration coefficients used to transform the values from the image to absolute radiance values. Typically, this information is provided with the data set as an offset and a gain for each channel. The specified text file should contain the band number, offset and gain, and the units for each. The following shows an example of a calibration file for SPOT Landsat-7 images:
7 c0 c1 [mW/cm2 sr micron] 1 -0.6200 0.0776000 2 -0.6400 0.0796000 3 -0.5000 0.0619000 4 -0.5100 0.0637000 5 -0.1002 0.0126000 6 0.0000 0.00670866 7 -0.0350 0.00437000
Also, if no value is specified for Calibration File, or if the coefficients cannot be derived from the metadata, an error message will be displayed.
Remove Small Clouds
Selected by default, this check box controls whether to remove small clouds from the output imagery.
You must enter a value for Minimum Size and select a value for Unit.
Minimum Size
The size of clouds smaller than the minimum to remove based on the value selected for Unit.
When you specify a value, you must select a value for Unit.
Unit
Smooth Cloud Polygons
Select this check box to smooth the cloud polygons to provide continuous change in curvature.
When selected, the smoothing algorithm cuts through some pixel edges rather than following the actual edge of each pixel.
Remove Haze
Select this check box to remove haze and, therefore, create haze-corrected (HZC) image files.
Haze Coverage
The approximate percentage of coverage of hazy pixels in the image.
This value you specify determines the size of the haze mask to generate to identify haze pixels. You can base the percetage you specify on the total number of pixels in the image, excluding saturated pixels. By default, haze coverage is approximately 50 percent.
This parameter is optional.
| Back to top |
Preprocessing requirements
Before running this module, the following requirements must be met to ensure the job processes successfully and produces accurate results:
Ingested images: Input scenes must be multispectral or panchromatic orthorectified images or must have been processed using the Orthorectification module.
Valid input scenes must follow the standard PCI file-naming convention; that is, supported file names match the pattern *ORTHO_MS.pix.
Multispectral imagery: Input multispectral imagery must have, at a minimum, a blue or green band and a red band. For haze removal, the imagery must also contain a near-infrared (NIR) band.
Metadata tags: Creating the masks and removing haze from the image requires the presence of several metadata tags in the multispectral image file. If these tags are unavailable, processing of the job stops.
Module details
The input for the Cloud Detection and Haze Removal module is a folder of multispectral, orthorectified image scenes that have already been processed using the Orthorectification module. As such, the input files contain the “_ORTHO_MS” tag in the file name. For example:
<SCENE_ID>_ORTHO_MS.pix
The Cloud Detection and Haze Removal module reads the folder of input orthos for multispectral, orthorectified image scenes. A child job is created for each scene. The module generates coarse classification masks (HOTMASK file), which are used to perform the haze-removal operation for any of the supported multispectral sensors.
When the classification masks are created successfully, the haze-removal process is run on the multispectral image to create a haze-corrected (HZC) image.
Job results
© PCI Geomatics Enterprises, Inc.®, 2026. All rights reserved.