Sunday, December 21, 2008

Improving line pair resolution (Part 2)

Continuing our discussion of how you can improve the ability of your vision system to resolve fine details: The line-pair limit is also influenced by the wavelength of the light you are using. Shorter wavelength light yields better line pair resolution. So if you need to see fine detail, use blue light rather than red. (Incidentally, this is why infrared images – long wavelength light - have that characteristic fuzziness.)

And a final factor to consider is the size of the pixels in your sensor. For reasons I won’t go in to, (I’m an engineer, not a physicist!) smaller pixels are able to resolve line-pairs that are closer together. The downside of course is that small pixels catch fewer photons, meaning that you’ll need to throw more light on your target.

Machine vision really is all about trade-offs!

No comments: