Region Grow Properties

Region growing expands a selected area to include nearby pixels that fall within a threshold range of the current selection. See "REGION_GROW" (IDL Reference Guide) for additional details. For a description of how a particular control is used, refer to Property Controls.

Table C-30: Region Grow Operation Properties 

Property
Control Type: Options

Region grow method

String List: The method used to select pixels that are similar to the current selection. Choose from these values:

  • By threshold: The expanded region includes neighboring pixels that fall within the range defined by the Threshold minimum and Threshold maximum values.
  • By standard deviation: The expanded region includes neighboring pixels that fall within the range of the mean of the region's pixel values plus or minus the given multiplier times the sample standard deviation as follows:

    • Mean +/- StdDevMultiplier * StdDev

    where Mean is the mean value of the selected pixels, StdDevMultiplier is the value specified by the Standard Deviation Multiplier property, and StdDev is the standard deviation of the selected pixels.

Default = By threshold

Pixel search method

String List: Specifies which pixels should be considered during region growing. Four-neighbor searching searches only the neighbors that are exactly one unit in distance from the current pixel; Eight-neighbor searching searches all neighboring pixels.

Choose from these values:

  • 4-neighbor
  • 8-neighbor

Default = 4-neighbor

Threshold to use

String List: Specifies the threshold values to use. Choose from these values:

  • Source ROI/Image threshold: Base the threshold values on the pixel values in the currently selected region.
  • Explicit: Specify the threshold values using the Threshold minimum and Threshold maximum properties.

Default = Source ROI/Image threshold

Threshold minimum

Number: The explicitly specified minimum threshold value. Default = 0

Threshold maximum

Number: The explicitly specified maximum threshold value. Default = 256

Standard deviation multiplier

Number: The number of standard deviations to use if the region growing method is By standard deviation. Default = 1

For an RGB(A) image use

String List: If the image has separate color channels, use the selected channel when growing the region. Choose from these values:

  • Luminosity: Luminosity values
  • Red Channel: Red values
  • Green Channel: Green values
  • Blue Channel: Blue values
  • Alpha Channel: Transparency values.

Default = Luminosity