Imaging operators

Several context-sensitive pages in the Variable Properties dialog box are displayed for virtual variables. The pages that are displayed depend on the operator that was used to create the virtual variables.

One or more of the following virtual variable pages will be present if Imaging operators are used:

3 Color Maximum
GLCM Texture page

3 Color Maximum page

The 3 Color Maximum page is displayed on the Variable Properties dialog box if the 3 color maximum operator has been applied to create the selected virtual variable. Operand 1, 2 and 3 have the following settings:

Setting	Description
Color display minimum	Enter a value for the Color display minimum for the operand.
Minimum Color	Displays the Minimum color for the operand. Click the color to select a new Minimum color.
Color display range	Enter a value for the Color display range for the operand.
Maximum Color	Displays the Maximum color for the operand. Click the color to select a new Maximum color.

Notes:

The default colors on the 3 Color Maximum page do not represent pure RGB colors.
Display settings for a 3 color maximum virtual variable can be changed using keyboard shortcuts.

See the 3 Color maximum algorithm for more details.

GLCM Texture page

The Texture page is displayed on the Variable properties dialog box if the GLCM texture feature operator had been applied to create the selected virtual variable. This page allows you to select GLCM, gray level and texture feature settings. See About the GLCM and texture features for more information.

Setting

Description

Feature

Select a GLCM texture feature from the list:

Window size

Specifies the window size for the GLCM texture feature. The window size defines the area of samples used for GCLM tabulations and texture calculations.

Setting	Description
Length	Length of window (pings). The length is restricted to an odd number in the range 3 to 999.
Height	Height of the window (samples). The height is restricted to an odd number in the range 3 to 999.

Quantization

Specifies parameters so that sample intensity can be assigned to discrete gray levels for the calculation of the GCLM. Each gray level represents a range of sample intensity values.

Setting	Description
Minimum value	The minimum sample intensity value. This defines the start of the minimum gray level. Sample intensities below the Minimum value are assigned to the minimum gray level.
Maximum value	The maximum sample intensity value. This defines the end of the maximum gray level. Sample intensities above the Maximum value are assigned to the maximum gray level.
Number of levels	Specifies the number of gray levels between the Minimum and Maximum values. Restricted to a number in the range 2 to 256.

Notes:

No Data samples are not affected by quantization.
Boundary samples of the echogram (i.e. those for which the surrounding window is not filled with data) are assigned the No Data value.

Spatial Relationship

Defines the spatial relationship between the reference sample and the neighbor sample used in tabulations for the GLCM.

For example:

Direction = Horizontal, Distance = 1 defines the neighbor sample to be one sample to the right of the reference sample.

Setting

Description

Direction

Select the direction of the spatial relationship from the following list:

Horizontal
Vertical
Diagonally up
Diagonally down

Distance

Select the distance between the reference and neighbor sample (samples).

Imaging operators

3 Color Maximum page

GLCM Texture page

See also