IMAQ Get Geometric Features From Curves VI

LabView NI Vision

IMAQ Get Geometric Features From Curves VI

Owning Palette: Pattern Matching AdvancedInstalled With: NI Vision Development Module

Returns the geometric features described by a set of curves.

IMAQ Get Geometric Features From Curves

Curves is an array describing the curves found in the image.

	Points specifies the location of every point detected on the curve.
	Closed? is TRUE (Closed) when the distance between the endpoints of the curve are less than or equal to Max Endpoint Gap or FALSE (Open) when the distance between the endpoints of the curve are greater than Max Endpoint Gap.
	Curve Length returns the length of the curve.
	Min Edge Strength returns the lowest edge strength detected on the curve.
	Max Edge Strength returns the highest edge strength detected on the curve.
	Average Edge Strength returns the average of all edge strengths detected on the curve.

Feature Types to Extract are the types of features to extract from the passed curves. Pass an empty array to extract all features. The default value is an empty array.

error in (no error) describes the error status before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.

	status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE.
	code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code.
	source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.

Features is a list of geometric features associated with a match.

Feature Type is the type of geometric feature.

Feature Data is an array that describes the geometric feature. The elements of this array should be interpreted according to the feature type in the following manner:

Circle

Element 0—X coordinate of the center of circle.
Element 1—Y coordinate of the center of circle.
Element 2—Radius of circle.

Ellipse

Element 0—X coordinate of the center of ellipse.
Element 1—Y coordinate of the center of ellipse.
Element 2—Orientation in degrees of the major axis.
Element 3—The length of the semi-major axis.
Element 4—The length of the semi-minor axis.

Constant Curve

Element 0—X coordinate of the center of the constant curve.
Element 1—Y coordinate of the center of the constant curve.
Element 2—The starting angle in degrees of the constant curve.
Element 3—The ending angle in degrees of the constant curve.
Element 4—The radius of the circle subtended by the constant curve.

Rectangle/Leg

Element 0—X coordinate of the location of the center of the rectangle/leg.
Element 1—Y coordinate of the location of the center of the rectangle/leg.
Elements 2 and 3—The first corner point (x, y) of the rectangle/leg.
Elements 4 and 5—The second corner point (x, y) of the rectangle/leg.
Elements 6 and 7—The third corner point (x, y) of the rectangle/leg.
Elements 8 and 9—The fourth corner point (x, y) of the rectangle/leg.
Element 10—The orientation of the rectangle/leg in degrees with respect to the horizontal axis.
Element 11—The width of the rectangle/leg.
Element 12—The height of the rectangle/leg.

Corner

Element 0—X coordinate of the corner position.
Element 1—Y coordinate of the corner position.
Element 2—The orientation of the corner.
Element 3—The enclosed angle of the corner.
Element 4—Specifies whether or not the corner is a virtual corner. A value of 0 means that the corner is not a virtual corner. A value of 1 means that the corner is a virtual corner.

Parallel Line Pair

Elements 0 and 1 —The start point (x, y) of the first line.
Elements 2 and 3—The end point (x, y) of the first line.
Elements 4 and 5—The start point (x, y) of the second line.
Elements 6 and 7—The end point (x, y) of the second line.
Element 8—The orientation in degrees of the parallel line pair with respect to the horizontal axis.
Element 9—The distance of the two lines from one another.

Parallel Line Pairs

Elements 0–9—The first parallel line pair.
Elements 10–19—The second parallel line pair.
Element 20—The orientation in degrees of the pair of parallel line pairs with respect to the horizontal axis.
Element 21—The distance the two parallel line pairs are from one another as measured by the midline of the first to the midline of the second.

Line

Elements 0 and 1—The start point (x,y) of the line.
Elements 2 and 3—The end point (x,y) of the line.
Element 4—The length of the line.
Element 5—The orientation in degrees of the line with respect to the horizontal axis.

Closed Curve

Elements 0 and 1—The center point (x,y) of the closed curve.
Element 2—The arc length of the closed curve element.
Elements 3 and 4—The first of N contour points (x,y) of the closed curve.
Elements 5 and 6—The second of N contour points (x,y) of the closed curve.
Elements k and k+1—The (k–1)/2 contour point (x,y) of the closed curve.

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Elements 2*N+1 and 2*N+2—The last of N contour points (x,y) of the closed curve.

error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces. Right-click the error out indicator on the front panel and select Explain Error from the shortcut menu for more information about the error.

	status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred.
	code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code.
	source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.

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