ThresholdBlockSize Property

Applies To
Vision Objects: Blob, Contour, ImageOp

Description
Sets or reurns the size of the square pixel neighborhood used to calculate mean intensity for a given pixel. The size of pixel neighborhood is set based on that of search window (ROI, Region of Interest).

Usage

VGet  Sequence.Object.ThresholdBlockSize, var
VSet  Sequence.Object.ThresholdBlockSize, value

Sequence

Name of a sequence or string variable containing a sequence name.

Object

Name of an object or string variable containing an object name. The object must exist in the specified sequence.

var

Integer variable that will contain the value of the property.

value

Integer value or expression for the new value of the property.

Values

• 1 - 1/4 ROI
  • Vision constant: VISION_THRESHBLKSIZE_1_4_ROI
  • Calculate the mean intensity in the size of ROI×1/4.
• 2 - 1/8 ROI
  • Vision constant: VISION_THRESHBLKSIZE_1_8_ROI
  • Calculate the mean intensity in the size of ROI×1/8.
• 3 - 1/16 ROI
  • Vision constant: VISION_THRESHBLKSIZE_1_16_ROI
  • Calculate the mean intensity in the size of ROI×1/16.
• 4 - 1/32 ROI
  • Vision constant: VISION_THRESHBLKSIZE_1_32_ROI
  • Calculate the mean intensity in the size of ROI×1/32.
• 5 - 1/64 ROI
  • Vision constant: VISION_THRESHBLKSIZE_1_64_ROI
  • Calculate the mean intensity in the size of ROI×1/64.

Default: 3 - 1/16 ROI

Remarks
ThresholdBlockSize is the size of the square pixel neighborhood used to calculate mean intensity for a given pixel. The size of pixel neighborhood is set according to a percentage of ROI width and the setting value is selected from "1/4 ROI, 1/8 ROI, 1/16 ROI, 1/32 ROI, 1/64 ROI". Local changes of intensity can be detected when the percentage of ROI width decreases. Note that if an object is small, the object image may not be binarized properly when decreasing the percentage of ROI width too much.

See Also
Blob Object, Contour Object, ImageOp Object, ThresholdLevel Property