IMAQ MultiThreshold VI

LabView NI Vision

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IMAQ MultiThreshold VI

Owning Palette: ProcessingInstalled With: NI Vision Development Module

Performs thresholds of multiple intensity ranges to an image.

Details Examples

IMAQ MultiThreshold

Image Src is a reference to the source image.

Image Dst is a reference to the destination image.

Threshold Data is an array of clusters specifying the mode and threshold range. This operation is analogous to the process in the IMAQ Threshold VI. Each cluster is composed of the following elements:

	Lower value is the lowest pixel value to be taken into account during a threshold. The default is 128.
	Upper value is the highest pixel value to be taken into account during a threshold. The default is 255.
	Replace Value is the value used to replace pixels between the Lower value and Upper value. This operation requires that Keep/Replace Value (Replace) is TRUE.
	Keep/Replace Value (Replace) determines whether to replace the value of the pixels existing in the range between Lower value and Upper value. The default status, TRUE, replaces these pixel values, and the status FALSE keeps the original values. 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 (Replace) is TRUE.

error in (no error) describes the error status before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.

	status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE.
	code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code.
	source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.

Image Dst Out is a 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 contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces. Right-click the error out indicator on the front panel and select Explain Error from the shortcut menu for more information about the error.

	status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred.
	code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code.
	source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.

Details

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 VI 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 VI.

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.

Examples

Refer to the following for an example that uses this VI.

LabVIEW\examples\Vision\3. Applications\Circle Distance Example.vi

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