Appendix C: 2D Code Tutorial
19
Adjusting the lighting
When attempting to read a degraded code, the first step is to ensure the image quality is as
high as possible. Choosing the correct lighting setup can save hours of design. The image of
the dot-peen code shown in Figure C-1 was achieved using a low angle LED ring light at very
low level. The light cannot enter and reflect from the pits because of the light’s low angle, so the
pits appear black. Light is reflected readily off the metal surface, which appears light gray.
Some light is reflected from the rim of the pits, which appears to give each pit a bright halo. As
shown in Figure C-2, applying an image filter eliminates this halo effect. For additional lighting
information, see
or contact Cognex Technical Support.
Figure C-2. Filtered Image of 2D Code
