Size and species grading of fish
The fish passes on a wet belt under a 3D laser profiler; length, body thickness and volume are measured from the height map. A colour camera above takes an image for species separation, and diverter flaps route the fish to the crate of its grade.
Length, thickness, estimated weight and grade of every fish are sent to the PLC, which opens the flap when the fish reaches it. Count and total weight per grade are written to the production record.
- 01 Infeed
- 02 3D scan
- 03 Colour image
- 04 Grade
Fish arrive at the station one by one on the wet belt.
- Length
- —
- Body thickness
- —
- Estimated weight
- —
Scenes are illustrative simulations; they are not customer references or performance guarantees.
Need
Fish are wet and shiny; water and scales cause glare in a 2D image and the outline is not found reliably on a dark belt. A fish may lie skewed or curved on the belt, and the weight grade cannot be derived from length alone: body thickness is needed too.
Solution approach
The laser line falls across the belt; each profile of the passing fish is a cross-section, and the sections are merged into a height map. The map is unaffected by glare and belt colour: length is measured along the body axis, thickness at the highest section, and the weight grade is estimated from volume. Species are separated by pattern and body proportions in the ring-lit colour image.
Process steps
- 01
Infeed
Fish arrive at the station one by one on the wet belt.
- 02
3D scan
The laser line scans the fish from head to tail and the height map builds up.
- 03
Colour image
The ring light strobes and a colour image is taken for species separation.
- 04
Grade
The grade is assigned from length, thickness and species; the matching flap opens.
Related applications
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