Analytic Geometry Measurements; Instrument Reader Measurements - National Instruments IMAQ Vision for Measurement Studio User Manual

Analytic Geometry Measurements

Instrument Reader Measurements

© National Instruments Corporation
Use the following functions to make geometrical measurements from the
points you detect in the image:
•
imaqFitLine()
equation of the line.
•
imaqFitCircle()
computes its area, perimeter and radius.
•
imaqFitEllipse()
computes its area, perimeter, and the lengths of its major and minor
axis.
•
imaqGetIntersection()
specified by their start and end points.
•
imaqGetAngle()
•
imaqGetPerpendicularLine()
from a point to a line and computes the perpendicular distance between
the point and the line.
•
imaqGetBisectingLine()
formed by two lines.
•
imaqGetMidLine()
and a line and is parallel to the line.
•
imaqGetPolygonArea()
specified by its vertex points.
You can make measurements based on the values obtained by meter, LCD,
and barcode readers.
Use
imaqGetMeterArc()
read. The
imaqGetMeterArc()
two modes. The
IMAQ_METER_ARC_ROI
the full-scale position of the needle. When using this mode, the function
calculates the position of the base of the needle and the arc traced by the tip
of the needle. The
IMAQ_METER_ARC_POINTS
using three points on the meter: the base of the needle, the tip of the needle
at its initial position, and the tip of the needle at its full-scale position.
When using this mode, the function calculates the position of the points
along the arc covered by the tip of the needle. Use
read the position of the needle using the base of the needle and the array of
points on the arc traced by the tip of the needle.
—Fits a line to a set of points and computes the
—Fits a circle to a set of at least three points and
—Fits an ellipse to a set of at least six points and
—Finds the intersection point of two lines
—Finds the smaller angle between two lines.
—Finds the perpendicular line
—Finds the line that bisects the angle
—Finds the line that is midway between a point
—Calculates the area of a polygon
to calibrate a meter or gauge that you want to
function calibrates the meter using one of
mode uses the initial position and
5-27 IMAQ Vision for LabWindows/CVI User Manual
Chapter 5 Machine Vision
mode calibrates the meter
imaqReadMeter()
to