IMAQ Line Gauge VI

LabView NI Vision

IMAQ Line Gauge VI

Owning Palette: CaliperInstalled With: NI Vision Development Module

Measures the distance between selected edges with high-precision subpixel accuracy. You can use different measurement modes with this VI, such as measuring distances between points and edges and vice versa. This VI also can step and repeat its measurements across the image. Depending on the type of the measurement, this VI first determines the relevant edges in the image before computing the distances.

IMAQ Line Gauge

Base Reference is the base coordinate system. This cluster contains the following elements:

	Origin is a point cluster that specifies the origin of the base reference coordinate system.
	Angle (deg) is the angle the base reference coordinate system makes with the image coordinate system.
	Axis Reference is defined as Direct or Indirect. Refer to Axis Type for more information.

SubPixel Information is a cluster containing the following parameters for subpixel analysis:

Interpolation Type specifies the method used to perform the interpolation. The following values are valid:

Quadratic (1)	Uses the quadratic formula to compute the pixel location
Cubic Spline (2)	Uses cubic splines to compute the pixel location

SubPixel Accuracy specifies the number of samples to obtain from a pixel. For example, a subpixel accuracy of One Fourth specifies that each pixel is split into four subpixels.

Image is a reference to the source image.

Line Coordinates is an array specifying the pixel coordinates that form the end points of the line.

Edge Parameters is a cluster defining the characteristics of the filter used to detect the edges. This cluster consists of the following parameters:

	Contrast specifies the threshold for the contrast of the edge. Only edges with a contrast greater than this value are used in the detection process. Contrast is defined as the difference between the average pixel intensity before the edge and the average pixel intensity after the edge.
	Filter width specifies the number of pixels that the VI averages to find the contrast at either side of the edge.
	Steepness specifies the slope of the edge. This value represents the number of pixels that correspond to the transition area of the edge.

Measurement Type specifies the type of measurement to perform. The following values are valid:

Note Subpixel information is not used when measuring distances between points.

Edge To Edge (0)	Measures the distance between the first and last edge locations along a line in the image.
Edge To Point (1)	Measures the distance between the first edge in the image and the end point of a line.
Point To Edge (2)	Measures the distance between the start point of the line and the first edge along the line of the image.
Point To Point (3)	Measures the distance between two points in the image.

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.

Offset Array is an array of point clusters that specifies the shift in the start and end points of the pixel coordinates. The Offset Array is used for repeating the measurement across the image.

New Reference is the new coordinate system.

This cluster contains the following elements:

	Origin is a point cluster that specifies the origin of the base reference coordinate system.
	Angle (deg) is the angle the base reference coordinate system makes with the image coordinate system.
	Axis Reference is defined as Direct or Indirect. Refer to Axis Type for more information.

Distances is an array containing the measured distances.

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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