MV4U logo explained

My little graphic (at the top of the page, if you haven’t already seen it,) features a twin-peaked histogram showing the grayscale intensity of a pair of white lines on a black surface.

You’ll notice that rather than having clearly defined edges, the white lines gradually fade to black. This is how your machine vision camera “sees” line pairs. (If you don’t believe me, grab a monochrome image and zoom in close on an edge.)

So what happens as the white lines move closer together? Well, the two peaks will begin to merge, ultimately to a point where it is no longer possible to separate them. The distance between the white lines at the point where we can no longer tell them apart is the diffraction limit.

This is why you’ll hear imaging professionals talk about line pairs. The number of line pairs per inch that a system can distinguish is a measure of its’ ability to resolve fine detail.

So now you might be wondering if there is anything you can do to improve the line-pair resolution of your system.

The answer is, yes, but I’m not going to tell you today. Check back soon for more details.