Sunday, October 28, 2012

A different approach to color imaging

Machine vision pros know it’s not always necessary to use a color camera for a color application. Often all that’s needed is to either match the wavelength of the illumination source to the target. Like colors lighten, so a red light will make a red target appear white(ish) to the camera. An alternative is to put a filter over the lens, so that only light of the target wavelength is allowed through.

But what if you need to look at several targets in several different wavelengths?

What you need then is a liquid crystal tunable filter. A product like VariSpec might do what you want, and something similar is available from Inno-Spec. And if you want to understand just how they might be used, I suggest you read “Tell-Tale Color Changes: Camera Can Find Age of a Bruise” on the BioPhotonics website, October 2012.

This fascinating article describes some important color imaging work going on in the medical field. I’m not going to steal their page views by telling you about it: click the link and read for yourself.

And last, if you want to understand more about how a liquid crystal tunable lens actually works, take a look at “Liquid Crystal Tunable Filters” on the Olympus Microscopy Resource Center site.

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