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Threshold (Multiple Threshold) (G Dataflow)

Last Modified: October 26, 2017

Performs thresholds of multiple intensity ranges to an image.

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image src

Reference to the source image.

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image dst

Reference to the destination image.

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threshold parameters

Array of clusters specifying the mode and threshold range.

Each cluster is composed of the following elements:

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lower value

Lowest pixel value to be taken into account during a threshold.

Default: 128

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upper value

Highest pixel value to be taken into account during a threshold.

Default: 255

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replace value

Value used to replace pixels between the lower value and upper value.

This operation requires that keep/replace value? is True.

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keep/replace value?

Boolean input that determines whether to replace the value of the pixels existing in the range between lower value and upper value.

All pixels outside the range between lower value and upper value are set to 0. All values found between this range are replaced by the value entered in replace value if keep/replace value? is True.

True Replaces the pixel values ranging between lower value and upper value.
False Keeps the original values of the pixels ranging between lower value and upper value.

Default: True

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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 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.

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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.

Threshold Operations

The threshold operations are performed in reverse order that the data is received from threshold data. A pixel can be taken into account only once, even if the pixel is included in the threshold range of more than one threshold by threshold data.

For example, a node contains two clusters on input:

Cluster 1 lower value = 80, upper value = 150, keep/replace value = TRUE, replace value = 255.
Cluster 2 lower value = 120, upper value = 200, keep/replace value = FALSE.

This example shows two threshold ranges with an overlap between 120 and 150. Therefore, the pixels between 120 and 150 are treated only by the second threshold. The following results occur after execution of this node.

  • Pixel values between 0 and 79 are replaced by 0.
  • Pixel values between 80 and 119 are replaced by 255.
  • Pixel values between 120 and 200 keep their original values.
  • Pixel values greater than 200 are replaced by 0.

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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