Prior to inspection the containers are rotated at high speed to whirl up any particle. As soon as the products appear in front of the camera, the rotation is stopped. The liquid inside the containers continues to rotate and a sequence of images is taken. The images are compared to each other in the image processor. Objects which have shifted their location between the sequence of images are detected as particles.
Even very small location changes of particles can be detected, which is very important inspecting viscous liquids. Heavy non-moving particles can also be detected with special vision tools.
For particle inspection a combination of light technology is used
Light transmission method where particles cast shadows which are registered by the cameras
Light reflection method where particles are illuminated to scatter light which is registeredby the cameras
Polarized background light for special applications
