A while back I had the pleasure of meeting Spencer Luster, owner of a small business called Light Works. Spencer has earned himself a reputation as an authority on the subject of telecentricity, which is something of a niche even within the rarefied world of machine vision. Nevertheless, it’s a topic we vision professionals all need to grasp.
For the uninitiated, I can best define telecentricity as the opposite of perspective. You know how something looks smaller when it’s further away? Well that’s perspective, and for a vision system it can be a real .b***h. It’s the conical view from a standard lens that causes the problem, which is especially severe if you’re trying to make measurements over a non-flat surface. Let me add a small sketch to illustrate.
Spencer has some great information on his web site about how to use telecentric lenses to deal eliminate the perspective problem, and a great range of products too. I recommend starting with his FAQ He also had a great primer on the subject published in Vision Systems Design. Here’s a link to that article.
For the uninitiated, I can best define telecentricity as the opposite of perspective. You know how something looks smaller when it’s further away? Well that’s perspective, and for a vision system it can be a real .b***h. It’s the conical view from a standard lens that causes the problem, which is especially severe if you’re trying to make measurements over a non-flat surface. Let me add a small sketch to illustrate.
Spencer has some great information on his web site about how to use telecentric lenses to deal eliminate the perspective problem, and a great range of products too. I recommend starting with his FAQ He also had a great primer on the subject published in Vision Systems Design. Here’s a link to that article.
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