Two Netherlands-based companies have developed an automated inspection system that sorts shrimp and returns crabs and other small fish unharmed back into the sea.
The system was developed by an Austrian automation company in tandem with a company that specializes in the shrimp fishing industry. In addition to identifying and sorting shrimp, the inspection system can identify objects that need to be returned to the sea, including small fish, and crabs, some of which are endangered species.
Two UI-5240RE GigE cameras from IDS Imaging Development Systems (Obersulm, Germany; www.ids-imaging.com) are used in the system. These feature 1.3MPixel CMOS image sensors from e2v (Chelmsford, UK; www.e2v.com) that can run at 50 fps. In addition, the cameras have an IP67 enclosure-including magnesium housing, lens barrels, and lockable connectors.
After a vacuum system brings in the catch and distributes it on a conveyor belt, the two GigE cameras capture images of the individual objects as they pass through. The software used for image processing is based on a script from MVTec's (Munich, Germany; www.mvtec.com) HALCON, and is used to identify shrimp in three different size categories. A controller receives the image data via the Ethernet connection and different air nozzles transport the shrimp by size into the appropriate container.
With the system, 10 to 20 images can be analyzed per second, depending on the speed of the belt. Up to 300 kilograms of shrimp can be sorted per hour.