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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 for additional details. For a description of how a particular control is used, refer to Property Controls.

Table C-30: Region Grow Operation Properties 

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

  IDL Online Help (March 01, 2006)