Thursday, January 12, 2012

Shouldn’t autofocus be standard?

I make it a requirement that I have remote access to all my installed vision systems. This saves me much time and money in travelling to factories to make a simple change in the way a system works. However, there remain two classes of problem that still require site visits: lighting and optics.

If you’re wondering why, I take it you’ve never tried to advise a technician at the end of a phone on how to focus an image, while watching the result live over the internet. “Turn the focus ring left …. No, that’s the aperture. The other ring … no, the other way …. No, turn the ring the other way. Too far…”

Autofocus lenses exist and zoom technology is commonplace in traffic control, (AVT have a solution,) but we haven’t really adopted them in machine vision. I think it’s time that changed. Of course, this will force a shift in camera design since the commands to the lens will pass through the camera, but I don’t see any real obstacles to doing that.

Not only would this help maintenance, it would also mean the lens could become a change part. If a system needed one field-of-view for a large part and a much smaller FoV for a second, then why not just change lenses? At the moment I would never propose doing this because the focus will never go back the same way twice, but with autofocus that problem goes away.

That just leaves lighting problems that need a site visit. Brightness I can control through software, but the angle? Has anyone considered applying optics technology to lighting?

1 comment:

Thor said...

AutoFocus is an advanced feature in my mind it fails to comply with the rule : "Keep it simple". It might see harmless and beneficial but it adds cost, complexity - the autofocus might fails top working after 5 years - it might also reduce the accuracy.

I personally prefer locking screws and never change anything - that is both simple and safe.