Table Of Contents

Get LCD ROI (G Dataflow)

Last Modified: June 25, 2019

Locates a seven-segment display within an area of interest.

The display can contain multiple digits. To find the area of each digit, all of the segments of the seven-segment indicator must be activated. This node is designed for seven-segment displays that use either LCDs or LEDs composed of electroluminescent indicators or light-emitting diodes and is resistant to light drift. It returns the area of interest containing the global rectangle for each digit. You can pass this ROI descriptor directly to the Read Meter node.

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LCD/LED?

Boolean that controls the indicator type.

TRUE LED indicators.
FALSE LCD indicators.

Default: FALSE

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image in

Reference to the source image.

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ROI descriptor in

Descriptor that defines the rectangle or rotated rectangle region of interest that contains each digit.

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Global Rectangle

Coordinates of the bounding rectangle.

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Contours

Individual shapes that define an ROI.

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ID

Object specifying if contour is the external or internal edge of an ROI.

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Type

Shape type of the contour.

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Coordinates

Relative position of the contour.

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threshold

Threshold that determines whether a segment is on or off.

A segment is considered on if the standard deviation of the pixels along a line profile across the segment is greater than this threshold. Increase this value when using images with high contrast. Lower this value when using images with low contrast.

Default: 8

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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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ROI descriptor out

Descriptor containing bounding rectangles of all the digits found by the algorithm.

The bounding rectangle of each located digit is specified as a rectangle contour in the returned ROI descriptor.

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global rectangle

Coordinates of the bounding rectangle.

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contours

Individual shapes that define an ROI.

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ID

Control specifying whether the contour is the external or internal edge of an ROI.

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type

Shape type of the contour.

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coordinates

Relative position of the contour.

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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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