Photogrammetry gets real for control

Processes dependant on exact shape and size can now be monitored in real time in 3D. Pilot applications range from monitoring the production of gobbets of molten material, to controlling the surface of fast fermenting rubbish. The technology comes from Adam Technology in Belmont, Australia. Adam is an acronym for Advanced Design And Manufacturing. Adam engineer Nathan Wasley explained to Eureka that the company's business originally started out off with the manufacture of analytical photogrammetric systems and software - taking overlapping stereo pictures and turning them into 3D digital models that can be analysed, measured and examined from different angles. The applications were for map compilation and also in open pit mine surveying. From this, the company has moved onto undertaking 3D photogrammetry in real time for control purposes. The first industrial application is in measuring the volumes of white-hot molten objects as they fall from a production line machine in Japan. The objects are supposed to each be 140 cm3 in volume. The system uses three CCD cameras kept cool by water jackets in order to survive the 1,200 deg C ambient temperature. The cameras are 10m apart and take the images simultaneously. The PC based analytical system determines the positions in space of several hundred points, several times per second. The vision system places a control frame round the areas of the molten gobbets as they fall, in order to reduce the vibration in the actual production error. Objects greater or less in volume than they should be trigger an alarm. Another pilot project, according Peter Jones, one of the Adams senior staff, is to use four CCD cameras aimed at the surface of material in large rubbish composting bins, also in Japan. Composting allows the reduction of waste volume, and the production of a more stable material for landfill, than typical municipal rubbish produced in the UK. The composting process depends on keeping the surface of the material level and at a certain height. Control requires sending in a grab to remove material from high spots to be dumped in low spots. The process generates a substantial amount of heat, which is monitored by additional infra red cameras, in order that the control system can direct water sprays onto hot spots. There are presently four pilot installations, with plans to go into full production. The technology looks fairly low cost, and could be used with benefit to control many processes handling solid or semi solid materials. Adam Technologies Pointers * Manufactured volumetric objects can now be monitored in real time for correct size and shape * The same technology may also be applied to surfaces of material in hoppers and bins in large scale process control