ReadMeter Method

NI Vision for Visual Basic

ReadMeter Method

Syntax

CWIMAQVision.ReadMeter SourceImage, MeterArc, Percentage [, NeedleEndpoint]

Return Type

Long

On success, this method returns 0. On failure, this method returns a negative number.

Purpose

Reads the position of a needle using the information in a CWIMAQMeterArc object. The method reads VU-meters with a dark needle on a light background or with a light needle on a dark background. It returns the location of the tip of the needle as a percentage of the full range of the meter.

Remarks

Use this method with U8, I16, and SGL images.

Parameters

SourceImage As CWIMAQImage

The image containing the meter.

MeterArc As CWIMAQMeterArc

Information about the arc of the meter.

Percentage As Double

On return, the angle of the needle as a percentage of the full-scale angle.

NeedleEndpoint As Variant

[Optional] On return, a CWIMAQPoint containing the location of the endpoint of the needle.

Example

Meter Example