|
|
|
|
Each product is inspected in up to three particle inspection stations using the image subtraction method:
1 Container and liquid are rotated at high
speed by servo drives in each position of
the inspection carousel.
2 Rotation of container is stopped, the liquid
continues to move, particles move with the
liquid.
3 A central inspection mirror moves synchro-
nized with the transport of the container.
4 The camera acquires a sequence of
image A - F.
5 The images are sent to the image processor
and are compared to each other in an overlay
image, pixel by pixel.
Objects which change their location between image A and F (i.e. objects moving with the liquid) are identified as defects. Dust or light scratches on the container surface are not changing their position between the images and are therefore not rejected in this inspection. Using two or three particle inspection stations allow to vary the rotation speeds to detect lighter and heavier particles.
The set points for rotation speed and brake point are stored together with the product inspection configuration (recipe) for each product.
Programmable servo drives in every position of the inspection carousel allow reproducible rotation distances and rotation speeds. No belt drives - no abrasion.
Depending on product range and container type different 
illumination techniques and combinations can be used.
------------------------
back
