Tuesday, February 9, 2010

How to set up your telecentric measurement system

You should by now understand that conventional lenses provide a conical view and so are subject to distance-scale effects. (In other words, objects further away look smaller.) You should also know that this makes it difficult to obtain accurate measurements by machine vision, unless you’re using a telecentric lens.

But just purchasing the lens isn’t enough. For really repeatable results you will also need a collimated light source, which you’ll have to align very carefully with the camera. You’ll also want to do a proper grid calibration to take out any optical distortion.

Opto Engineering, a relative newcomer in the world of machine vision optics, recently uploaded a video on this subject to YouTube. But as I’m a helpful guy, (and always on the look out for content,) I thought I’d embed it here for your education and delight.

Still need to learn more about telecentricity in machine vision? Well go up to that search box top left and type in “telecentricity”: you’ll find I’ve written several primers on the subject.

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