Table Of Contents

Clamp (Clamp (Vertical Max)) (G Dataflow)

Last Modified: June 25, 2019

Measures a distance in the vertical direction, from the horizontal sides of the search area toward the center of the search area.

This node locates edges along a set of parallel search lines, or rake. The edges are determined based on their contrast and slope.

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image in

Reference to the source image.

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search rectangle

Coordinates of a rectangular search area.

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left

X-coordinate of the upper left corner of the rectangle.

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top

Y-coordinate of the upper left corner of the rectangle.

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right

X-coordinate of the bottom right corner of the rectangle.

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bottom

Y-coordinate of the bottom right corner of the rectangle.

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rotation

Rotation angle in degrees of the rectangle with its center as point of rotation.

If the rotation angle does not equal zero, the left, top, right, and bottom coordinates are not the actual coordinates of the upper left and bottom right corner of the rectangle. Instead these coordinates are a position, if the rotation angle equals zero.

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options

Cluster defining the parameters of the edge detection algorithm and the information that is overlaid on the result image.

The first three parameters specify the filter used to detect the edges.

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contrast

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.

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filter width

Number of pixels that the node averages to find the contrast at either side of the edge.

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steepness

Slope of the edge.

This value represents the number of pixels that correspond to the transition area of the edge.

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Subsampling Ratio

Number of pixels that separate two consecutive search lines of the rake.

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show search area

Boolean that specifies if the ROI is overlaid on the image.

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show search lines

Boolean that specifies if the search lines used to locate the edges are overlaid on the image.

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show edges found

Boolean that specifies if the locations of the edges found are overlaid on the resulting image.

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Show Result

Boolean input that determines whether the hit lines to the object are overlaid on the result image.

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coordinate system

Coordinate system to which the rectangle is linked.

If the coordinate system input is used (connected), the location of the intensity measurement is shifted and rotated by the difference between the reference position of the coordinate system and its new location.

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error in

Error conditions that occur before this node runs.

The node responds to this input according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Default: No error

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image out

Reference to the destination image.

The search area and/or the result of the measurement can be overlaid on the image according to the settings.

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distance

Distance measured between the hit lines.

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edge coordinates

Array of point clusters consisting of the spatial coordinates of the detected edges.

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coordinate system dup

Reference to the coordinate system.

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error out

Error information.

The node produces this output according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Horizontal Hit Lines

A horizontal hit-line to the object is calculated through the uppermost edge detected. A second horizontal hit-line to the object is calculated through the lowermost edge. The distance between those two lines is returned. Clamp Vertical Max can overlay on the image returned: the position of the search area, the search lines, the edges found and the result.

Where This Node Can Run:

Desktop OS: Windows

FPGA: Not supported

Web Server: Not supported in VIs that run in a web application


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