Healthy knots are usually not associated with high contrasts so that they frequently remain ‘invisible’ to automatic inspection systems. But using the option for detecting healthy knots allows healthy knot structures to be automatically detected at speeds of more than 230 m/min.

This option uses a laser-scanning system that exploits the tracheid effect. Healthy knots from five millimetres and splay knots from 10 millimetres can be reliably detected and taken into account during further processing.

The module uses an additional laser and camera that are integrated on a joint platform installed at the detection station.

The results are determined in a separate analysis that is executed in parallel to the standard analysis and then used along with the other inspection data to assess the quality.