Colour Gem Sorter: Overview
Here’s how the machine worked:
Mined material fell from a conveyor, in front of a line-scan camera. While the stones continued to drop through the air, individual stones were identified and classified into waste or gem categories. When a gem stone was identified, an air jet was activated as the stone fell in front of it, ejecting the gem into a hopper. Waste material was allowed to fall onto a waste conveyor.
Because the air jets were only 30cm below the camera line, image processing had to be very fast and reliable. We made this real-time software as simple as possible, moving as much “intelligence” as possible into the calibration system. Even so, the sorter program had 12 simultaneous threads of execution.