CROSSMOD

Description

Cross-correlates the 'original' image band with the 'reference' band to produce B0 and B1 coefficient matrices. Normally, IMGFUSE is used to automate the entire fusion process. IMGLOCK can be used to automate the image locking process.

Parameters

Name	Type	Length	Value range
InputRef: Input reference image channels *	Raster port	1 - 1
InputORG: Input original image channel *	Raster port	1 - 1
OutputB0: Output channel for B0 *	Raster port	1 - 1
OutputB1: Output channel for B1 *	Raster port	1 - 1
Maximum Model Gain	Float	0 - 1	0.0 - 255.0 Default: 3.0
Kernel Size	Integer	0 - 1	1 - 100 Default: 7
Report	String	0 - 192	See parameter description

* Required parameter

Parameter descriptions

InputRef: Input reference image channels

Specifies the image channel to be used as the image reference in the algorithm. This should be an 8-bit unsigned image channel.

InputORG: Input original image channel

Specifies the input channel that contains the original image. This should be an 8-bit unsigned image channel.

OutputB0: Output channel for B0

Specifies the image channel to receive the output B0 image. This should be a 32-bit real image channel.

OutputB1: Output channel for B1

Specifies the image channel to receive the output B1 image. This should be a 32-bit real image channel.

Maximum Model Gain

Specifies the maximum model gain to be used for the modeling process.

Lower maximum gain values reduce the tendency of the algorithm to introduce noise into otherwise low texture or structured areas such as water regions. A typical starting value for this parameter is 3. If there is resulting noise in the water regions, reduce the maximum gain value. Note that reducing this value to less than 1 will result in blurred edges.

Kernel Size

Specifies the size of the linear kernels over which the cross-correlation modeling is performed.

Correlation is performed on a window size of ( 2 * KSIZE + 1 ) pixels. Sizes of less than 3 will produce noisier images; sizes greater than 7 will blur edges.

Report

Specifies where to direct the generated report.

Available options are:

• LOG: generates a report on the terminal (default)
• <modulename.RPT>: appends a report to the module's RPT file
• DISK: generates a report on file "IMPRPT.LST"

Details

CROSSMOD performs a cross correlation between the reference image and the original image. A horizontal and vertical kernel of KSIZE length is created. As this kernel scans across the window, the merit of both the horizontal and vertical kernels is evaluated. The correlation coefficients (B0 and B1) of the kernel with the best merit are then saved to the output file.

When spatial enhancement is performed, the amount of detail from the reference image that will be fused into the output image can be controlled by specifying the maximum gain (MAXGAIN); this parameter sets the upper limit of the B1 coefficient of the kernel with the best merit. For example, setting the maximum gain to 0 produces the original input file as output; there will be no spatial enhancement.