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Get Points on Contour (G Dataflow)

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Last Modified: October 26, 2017

Finds the number of edge segments in an image and returns the coordinates of the pixels in each segment.

Any pixel that is greater than 0 is considered an edge location. This node joins adjoining edge pixels into edge segments. An edge segment is considered closed if it forms a loop. Each edge segment is given a weight based on the pixel gray values along that edge. An edge segment with high gray values has a higher weight.

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edge image

Reference to the source image.

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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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edge image dup

Reference to the source image.

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segment information

Array of clusters with data from number of points, open/closed, weight, and contour points.

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number of points

Number of points that make up the edge segment.

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open/closed

Output that indicates if the edge segment is open or closed.

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weight

Output that indicates the significance of the edge in terms of the gray values that constitute the edge.

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contour points

Array of clusters, where each point on the edge is represented by coordinates.

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x

X-coordinate value of the edge point in the image.

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y

Y-coordinate value of the edge point in the image.

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curvature

Change in slope at this edge point of the segment.

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x displacement

X displacement of the current edge pixel from a cubic spline fit of the current edge segment.

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y displacement

Y displacement of the current edge pixel from a cubic spline fit of the current edge segment.

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number of segments

Number of edge segments in the image.

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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.

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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