SPECLINCMB

Description

SPECLINCMB performs a spectral linear combination of image channels using the coefficients you specify.

Parameters

Name	Type	Caption	Length	Value range
FILI *	String	Input file name	1 - 192
DBIC	Integer	Input channels	0 -	1 -
FILO *	String	Output file name	1 - 192
FTYPE	String	Output file type	0 - 4
FOPTIONS	String	Output file options	0 - 64
COEF *	String	Coefficients for image channels	1 - 192
MONITOR	String	Monitor mode	0 - 3	ON, OFF Default: ON

* Required parameter

Parameter descriptions

FILI

The name of the input file.

The file must be GDB-supported type that contains the image data to use in the linear combination.

DBIC

The channel or channels in the input file to process.

If you do not specify a value, all channels in the input file are used.

This parameter is optional.

Ranges of channels or segments can be specified with negative values. For example, {1,-4,10} is internally expanded to {1,2,3,4,10}. When you are not specifying a range in this way, only 48 numbers can be specified explicitly.

FILO

The path and file name of the output file to which to write the results of the process.

You cannot overwrite the input file.

Note: The bit depth of the output image channels is that of the input channels.

FTYPE

The format of the output file.

The format must be a GDB-supported type.

If you do not specify a value, the format of the input file is used, if supported. If you specify a file name, but not the file name extension, the PCIDSK format (.pix) is used.

FOPTIONS

The options to use when creating the output file, which are specific to each format.

For example, with some formats, you can select compression schemes, subtypes, and more.

For a complete list of GDB-recognized file types, including the available options for each, see GDB-supported file formats.

This parameter is optional.

COEF

The coefficients to apply to the input file during processing.

You can specify the value as either a list or a text file.

The format for the list is as follows:

1.0,0.0,0.0,0.0; 0.0,0.91,0.0,0.09; 0.0,0.0,1.0,0.0; 0.0,0.0,0.0,1.0

In the preceding example, a unique set of coefficients for four image channels is specified. The order of the coefficient sets follows the order of the image channels in the input file. Typically, the order is as follows:

Blue
Green
Red
Near infrared (NIR)

You must provide coefficients for each input channel. Separate each coefficient set of an image channel with a semicolon (;). By default, all image raster channels are included.

If you do not provide coefficients for an input channel, a blank channel will be created and each pixel will be assigned a value of one (1).

In the following example, the third channel is replaced with a blank channel for each pixel assigned a value of one (1):

1.0,0.0,0.0,0.0; 0.0,0.91,0.0,0.09; ; 0.0,0.0,0.0,1.0;

In the next example, following, a new blank channel is created after the four input channels:

1.0,0.0,0.0,0.0; 0.0,0.91,0.0,0.09; 0.0,0.0,1.0,0.0; 0.0,0.0,0.0,1.0;;

When you specify a text file, you must specify the coefficients for each input raster channel on a separate line, as shown in the following figure:

In the preceding figure, a text file shows a unique set of coefficients specified for four image channels, each on a separate line. The order of the coefficient sets follows the order of the image channels in the input file. Typically, the order is as follows:

Blue
Green
Red
Near infrared (NIR)

The order of the channels you specify must be the same as the order of the channels in the input file.

MONITOR

The program progress can be monitored by printing the percentage of processing completed. A system parameter, MONITOR, controls this activity.

Available options are:

ON: Turns the monitor ON (default)
OFF: Turns the monitor OFF (recommended if running in batch or background mode)

Details

SPECLINCMB performs a spectral linear combination of channels in an input image using the coefficients you specify, and then generates a new set of image channels.

The linear-combination process uses coefficients to determine the percentage of each image channel to combine to produce a single image channel.

If necessary, you can combine multiple image channels to a single image channel in the output file.

Example

In the following example, a new green image channel is generated by combining the green and NIR image channels based on the specified coefficients.

EASI>fili = "irvine.pix"
EASI>dbic = [1,2,3,4]
EASI>filo = "irvine_rgb.pix"
EASI>ftype = "PIX"
EASI>foption = ""
EASI>coef = "1.0,0.0,0.0,0.0; 0.0,0.91,0.0,0.09; 0.0,0.0,1.0,0.0; 0.0,0.0,0.0,1.0"

EASI>run SPECLINCMB

Environments	PYTHON :: EASI
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