Morphology (G Dataflow)

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Last Modified: June 25, 2019

Performs primary morphological transformations.

All source and destination image types must be 8-bit binary images. The connected source image for a morphological transformation must have been created with a border capable of supporting the size of the structuring element. A 3 × 3 structuring element requires a minimal border of 1; a 5 × 5 structuring element requires a minimal border of 2, and so on. The border size of the destination image is not important. This node modifies the source image. If you need the original source image, create a copy of the image using the Copy node before using this node.

image src

Reference to the source image.

image dst

Reference to the destination image.

operation

Type of morphological transformation procedure to use.

Name	Description
autoM	Auto median
close	Dilation followed by an erosion
dilate	Dilation (the opposite of an erosion)
erode	Erosion that eliminates isolated background pixels
open	Erosion followed by a dilation
Pclose	A succession of seven closings and openings
Popen	A succession of seven openings and closings

Default: autoM

number of iterations

Number of times the node performs a dilate or erode operation.

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

structuring element

2D array that contains the structuring element to apply to the image.

The size of the structuring element, or the size of this array, determines the processing size. A structuring element of 3 × 3 is used if this input is not connected.

square/hexagonal?

Boolean that specifies whether to treat the pixel frame as square or hexagonal during the transformation.

True	Hexagonal
False	Square

Default: False (Square)

image dst out

Reference to the destination image.

If image dst is connected, image dst out is the same as image dst. Otherwise, image dst out refers to the image referenced by image src.

error out

Error information.

The node produces this output according to standard error behavior.

Standard Error Behavior

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.

Morphology Behavior

A structuring element must have odd-sized dimensions so that it contains a central pixel. If one of the dimensions for the structuring element is even, the function does not take into account the odd boundary, farthest out on the matrix. For example, if the input structuring element is 6 × 4 (X = 6 and Y = 4), the actual processing is performed at 5 × 3. Both the sixth line and the fourth row are ignored. The processing speed is correlated with the size of the structuring element. For example, a 3 × 3 structuring element processes nine pixels, and a 5 × 5 structuring element processes 25 pixels.

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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