National Instruments IMAQ Vision for LabWindows TM /CVI - Manual (Page 66)

Chapter 5 Performing Machine Vision Tasks
IMAQ Vision for LabWindows/CVI User Manual 5-14 ni.com
Symmetry
A rotationally symmetric template, shown in Figure 5-7a, is less sensitive
to changes in rotation than one that is rotationally asymmetric, shown in
Figure 5-7b. A rotationally symmetric template provides good positioning
information but no orientation information.
Figure 5-7. Symmetry
Feature Detail
A template with relatively coarse features, shown in Figure 5-8a, is less
sensitive to variations in size and rotation than a model with fine features,
Figure 5-8b. However, the model must contain enough detail to identify the
feature.
Figure 5-8. Feature Detail
a. b.
a. b.