Description

Default method used to convert a bit mask into features.

Property type

A mcSetFromMaskMethod enumeration.  

Syntax

object.SetFromMaskMethod [= value]

The SetFromMaskMethod Property syntax has these parts:

PartDescription
objectAn expression evaluating to an object of type McLines.
valueA mcSetFromMaskMethod enumeration, as described in settings.

Settings

The settings for value are:

ConstantValueDescription
 mcsfmmDefault0

Default ordering. Currently this is the only acceptable value for McRegions (for McRegions, the source mask foreground bits are just used as foreground bits to be labeled for connected region features based on the state of the mcofConnect8 McFeatures.OptionFlags)

 mcsfmmPointsLeftTop1

For McPoints only, a point feature is set to left, top bit of each source mask blob.

 mcsfmmPointsCentroid2

For McPoints only, a point feature is set to the centroid bit of each source mask blob. The centroid is the mean X,Y coordinate of all foreground bits in the blob. Should the centroid fall between pixel centers, the point coordinates will be fractional values (see mcsfmmIntegralCentroidPoint for a way to ensure points placed on pixel centers).

 mcsfmmPointsIntegralCentroid3

For McPoints only, a point feature is set to the centroid bit of each source mask blob, rounded to the closest pixel center. The centroid is the mean X,Y coordinate of all foreground bits in the blob. Should the centroid fall between pixel centers, the point coordinates will be rounded to the nearest pixel center (see mcsfmmCentroidPoint for a way to place points on the fractional centroid). This is the default method for McPoints.Threshold and McPoints.SetFromMask.

 mcsfmmLinesLongestStraight10

For McLines only, a line feature is created as the straight line connecting the extreme points of each source mask blob. The extreme points are the two points on the boundary that are farthest apart from each other. This is the default method.

 mcsfmmLinesExtremeBoundaryAvg11

For McLines only, a line feature is created as a polyline traversing the extreme points of each source blob (the boundary points most distal from each other). Each point in this traversal is the average of coordinates perpendicular to the straight line connecting the extreme points (see mcsfmmLinesLongestStraight for a way to get this line). This method works well for blobs that define approximately straight lines but are asymetrical about the line (see mcsfmmMajorAxisAlignedLines for a similar method that works best for symetrical blobs). It will not work for lines that curve back on themselves (e.g. the letter “C”, any spiral shape, etcetera). Also, note that for rectangular input blobs, the line will be a diagonal one rather than a horizontal one; use the mcsfmmMajorAxisAlignedLines method to get a horizontal line.

 mcsfmmLinesMajorAxisAlignedAvg12

For McLines only, a line feature is created as a polyline traversing the longest bounds of a rectangle aligned along the major axis of an equivalent ellipse fit to each source blob. Each point in this traversal is the average of coordinates perpendicular to the long side of the rectangle. This method works well for blobs that define approximately straight lines through symetrical blobs (see the mcsfmmLinesExtremeBoundaryAvg for a method that may work better for asymetrical blobs). It will not work for lines that curve back on themselves (e.g. the letter “C”, any spiral shape, etcetera). Also, note that for rhombus shaped blobs, this method's lines will generally not align with the longest axis of the rhombus; use the mcsfmmLinesExtremeBoundaryAvg to get that behavior.

Remarks

The SetFromMaskMethod property is default the method used by SetFromMask in the absence of a Method argument. It is always the method that is used to set features when the Threshold property is used to set features from image luminance data.