Multi-resolution Reference Creator module

Description

The Multi-resolution Reference Creator module takes input reference images and creates various reference images to match a set of resolutions or projections. One reference image is generated for each input resolution and projection from the orthorectified images. The various resolutions are needed in the Super Registration module.

Parameters

Name	Caption
Reference Image	Path and file name of reference image
Output Folder	Output folder
Overwrite Results	Overwrite existing results
Input Orthos	The set of orthorectified imagery to process
Recreate Index Only	Whether to only recreate the index file
Resampling Method	Resampling method
Resampling Kernel File	Resampling Kernel File

Parameter descriptions

Reference Image

The path and file name of orthorectified images to use as reference.

Output Folder

The path and name of the folder to which to write the output files.

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.

Input Orthos

The name of the folder that contains valid, GDB-supported orthorectified images.

This parameter can be specified by using any of the following:

Path and name of a folder of input orthorectified images; for example, C:\data
Path and name of a folder with a wildcard to filter the imagery by file name or type; for example, C:\data\*ORTHO_MS.pix
You can also specify an MFILE as input. An MFILE is a text file with an .mfile file name extension. For more information on this type of file, see About the MFILE format.

Recreate Index Only

After generating all of the reference images, the Multi-resolution Reference Creator module creates an index file named index.txt.mfile in the output folder. The index file is needed by the Super Registration module.

This parameter is used to tell the job to recreate only the index file, rather than recreating all of the output reference images. It should only be used if, for some reason, you have lost the index file. Usually it should remain unchecked.

Resampling Method

The resampling method to use during processing.

Available resampling options are:

Cubic: cubic convolution. This method determines the gray level from the weighted average of the 16 pixels closest to the specified input coordinates and assigns that value to the output coordinates. The resulting image is slightly sharper than one produced by bilinear interpolation, and it does not have the disjointed appearance produced by nearest-neighbor interpolation. This is the default value.
Nearest Neighbor: nearest-neighbor interpolation. This method identifies the gray level of the pixel closest to the specified input coordinates and assigns that value to the output coordinates. Although this method is the most efficient in computation time, it introduces small offsets in the output image. The output image may be offset spatially by up to half a pixel, which may cause the image to have a jagged appearance.
Bilinear: bilinear interpolation. This method determines the gray level from the weighted average of the four closest pixels to the specified input coordinates and assigns that value to the output coordinates. An image with a smoother appearance than nearest-neighbor interpolation is created, but the gray-level values are altered in the process, resulting in blurring or degraded image resolution.
Sinc-8: eight-point sin(x)/x
Sinc-16: 16-point sin(x)/x
2D Kernel: 2D Kernel resample using the specified kernel file.

Resampling Kernel File

The custom resampling kernel file specifies a 2D kernel to be applied during the resampling.

The kernel file has a specific format. The first line indicates the number of columns and rows in the kernel:

				ColSize,RowSize

The subsequent lines consist of (ColSize * RowSize) kernel weights, listed one row per line:

				Weight_{1,1},...,Weight_{1,ColSize}
				.
				.
				.
				Weight_{RowSize,1},...,Weight_{RowSize,ColSize}

The following is an example of a kernel file specifying a 3x3 kernel:

				3,3
				0.01134374,0.08381951,0.01134374
				0.08381951,0.61934703,0.08381951
				0.01134374,0.08381951,0.01134374

This parameter is used only when the Reproject check box is selected and Resampling Method is set to "2D Kernel"; otherwise, it is ignored.

Details

General job details

Preprocessing requirements

Before running this module, the following requirements must be met to ensure the job processes successfully and produces accurate results:

The input orthorectified images and the reference images must have valid projections.
If the input orthorectified images and the reference images have exclusion masks then the masks must be in bitmap segments.

Module details

The Multi-resolution Reference Creator module resamples or reprojects the input reference image to the same resolution and projection as the input orthorectified images. If multiple input orthorectified images have the same resolution and projection then only one output file is created.

Job results

On successful completion, the Multi-resolution Reference Creator module creates various output reference images, one for each combination of projection and resolution of the input orthos. It also produces an index.txt.mfile in the output folder.

The output files match the following naming convention $ProjectionName_$XResx$YRes, where $ProjectionName is the Map Units of the file, $XRes is the resolution along the X axis, and $YRes is the resolution along the Y axis. The job produces filenames similar to UTM_34_C_D000_5.0x5.0.pix.
The index file produced is named index.txt.mfile. It lists all of the prepared reference images, their projections, and their resolutions. The index file helps determine the matching reference image used by the Super Registration module.