Defining Regions Programmatically; Find Measurement Points; Finding Features Using Edge Detection - National Instruments IMAQTM User Manual

Table 5-1. ROI Selection Methods to Use with CWMachineVision Methods (Continued)
CWMachineVision ROI Selection Methods
SetupViewerForPointSelection
GetSelectedPointFromViewer
SetupViewerForLineSelection
GetSelectedLineFromViewer

Defining Regions Programmatically

Find Measurement Points

Finding Features Using Edge Detection

© National Instruments Corporation
When you have an automated application, you need to define regions of
interest programmatically. You can programmatically define regions by
providing basic parameters that describe the region you want to define. You
can specify a rotated rectangle by creating a CWIMAQRotatedRectangle
object and setting the coordinates of the center, width, height, and rotation
angle. You can specify an annulus by creating a CWIMAQAnnulus object
and setting the coordinates of the center, inner radius, outer radius, start
angle, and end angle. You can specify a point by setting its x-coordinates
and y-coordinates. You can specify a line by setting the coordinates of the
start and end points.
Refer to Chapter 3, Making Grayscale and Color
information about defining regions of interest.
After you set regions of inspection, locate points in the regions on which
you can base measurements. You can locate measurement points using
edge detection, pattern matching, color pattern matching, and color
location.
Use the edge detection tools to identify and locate sharp discontinuities
in an image. Discontinuities typically represent abrupt changes in pixel
intensity values, which characterize the boundaries of objects.
Chapter 5
CWMachineVision Method
LightMeterPoint
LightMeterLine
5-9 IMAQ Vision for Visual Basic User Manual
Performing Machine Vision Tasks
Measurements, for more