Pixels: quantity, size and imaging performance

More pixels equal higher resolution, right?

Well, yes, but only up to a point. As the number of pixels goes up they get smaller. Smaller pixels have less light-collecting ability, simply because of their reduced area, but they also start to encounter the effects of the Airy disk.

Regular readers will guess that I’m about to dive in to another of my long-winded diatribes on the subject of diffraction, line pairs, MTF and so on. Well I’m not, but that doesn’t mean you don’t need to worry about matching your lens to your sensor, because you do.

If you want to produce sharp, high resolution images, I suggest you refer to my mini-series on the subject, beginning with “Selecting lenses for machine vision” (August 19th, 2009) and onwards. Then read “Matching Lenses and Sensors” by Greg Hollows and Stuart Singer (Vision Systems Design, March 2009) for an excellent – and much more complete – discussion of the subject.

Remember, success in machine vision flows from the quality of the image, so don’t skimp on lenses!