1.
The objects I want to detect - about 5%. The background slop - about 60%
2.
3.
Mostly. The sludge is random and linear in the direction of flow. The objects have some limited random motion and travel fairly reliably in the direction of flow.
4.
In theory good. In practice likely to wobble.
5.
Frames can be delivered as discrete jpegs at 5 per sec or as a digital cctv video stream. Processing power of an ordinary desktop PC.