This is a new area for us, and I'm looking for a place to start.
We want to detect presence or absence of an object (industrial, relatively large like 1m cube). When the object is sensed, it then triggers the next state in the processing. Like an assembly line.
Currently photoeye sensors are the norm, and work OK. The price isn't too bad, and wiring is only needed to one point.
There is a situation with oddly-shaped objects that might be "present", but may not break the photoeye beam because the front extended edge may be above or below the nominal level of the photoeye.
So let's do more photoeyes or a light curtain. Lots more wiring; lots more expense. It essentially multiplies the cost.
The idea being pursued is to use a CCD camera of some type, and essentially do a "motion detection" of some sort. In other words, have a reference frame of the "empty" state, and then detect the change to the "present" state. At this point we don't care about object identification or orientation verification though thise are obvious future extensions.
Where do I start for the most cost-effective solution? Looking for components it seems that buying a complete package like a WebCam or the bargain CVS digital camera is cheaper than trying to get the CCD, lens, power supply, etc. And included software or inexpensive software could do the task. But then there would be a whole PC involved, and a USB master, etc.
We certainly don't need 24-bit color. Monochrome would be enough. 320x240x1 gives about 10kB per frame; so an AVR with 32k of external storage could hold a couple of reference frames and the active frame.
One thing that would certainly need to be considered is varying light levels. Does flooding the area with our own infrared light source make any sense?
Let's say our industrial photoeye is a US$100 package. I'd like to target the same cost point but have a >>better<< system than the single-beam photoeye.
Main question 1: Where to start the research. Machine vision? Robotics clubs? WebCam software?
Main question 2: Would an AVR have enough horses to do even simple presence/absence detection as I outlined above?
Main question 3: Are there other approaches that might be better suited? E.g. ultrasound, radar, laser, ???
A totally new area for us. I'm sure some of the regular posters will be able to privide direction.