Rockwell Automation 5370-CVIM2 Module - Manual (Page 288)

Chapter 7
Inspection Tools
7–50
Theta Minor –– Theta minor measures the angle between the minor axis of
an object and the X–axis of the image field (assuming 0
° at the 3 o’clock
position). Since a clearly definable minor axis is required for this
measurement function to work properly, it cannot be used with circular
objects.
Figure 7.44 illustrates the theta angle of two identical elliptical objects with
different orientations in the image field. In this example, the minor axis of
object (A) is.52.2
° (clockwise) from the X–axis, while object (B) is –49.8°
(counterclockwise) from the X–axis.
Figure 7.44 Example: Theta Minor of Two Objects of Different Orientation
52.2
°
–49.8
°
A
B