Image processing at the speed of light

To begin at the beginning, unless your lens is properly matched to both the task your vision system is to perform and the camera you’ve selected, you will not get a high quality image. In other words, there’ll be some blurring, perhaps some fall-off in brightness towards the edges of the image, and a general lack of sharpness.

This will make your measurements, whether gauging a dimension, checking intensity, or counting blobs, less accurate than they might have been. Yes, you can use some software tools to clean up the image, but that takes processor time and can have unintended consequences, such as making a good part appear to be bad. Better by far to start with as good an image as you can. In other words, let the optics deliver a crisp image to your sensor.

So how do you get started with selecting optics? The first step is to understand the terminology involved, and one of the best places I’ve found for that is “Lens elements,” which can be found on the web site of Axis Communications.

Interestingly, Axis is in the security camera business rather than machine vision, but that hasn’t stopped them from providing a very easy to follow explanation of topics such as “field of view,” “F-number,” “lens mount standards,” and “Matching lens and sensor.”

Now here’s your assignment: Use the link I provided above to visit the Axis site. Spend twenty minutes or so on their “Lens elements” page, then check back with me Monday.