Table Of Contents
Clamp (Clamp (Vertical Max)) (G Dataflow)
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.
search rectangle
Coordinates of a rectangular search area.
left
X-coordinate of the upper left corner of the rectangle.
top
Y-coordinate of the upper left corner of the rectangle.
right
X-coordinate of the bottom right corner of the rectangle.
bottom
Y-coordinate of the bottom right corner of the rectangle.
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.
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.
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.
filter width
Number of pixels that the node averages to find the contrast at either side of the edge.
steepness
Slope of the edge.
This value represents the number of pixels that correspond to the transition area of the edge.
Subsampling Ratio
Number of pixels that separate two consecutive search lines of the rake.
show search area
Boolean that specifies if the ROI is overlaid on the image.
show search lines
Boolean that specifies if the search lines used to locate the edges are overlaid on the image.
show edges found
Boolean that specifies if the locations of the edges found are overlaid on the resulting image.
Show Result
Boolean input that determines whether the hit lines to the object are overlaid on the result image.
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.
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.
Default: No error
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.
distance
Distance measured between the hit lines.
edge coordinates
Array of point clusters consisting of the spatial coordinates of the detected edges.
coordinate system dup
Reference to the coordinate system.
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.
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