Measuring the outer shape of Pinus sylvestris saw logs with an X-ray LogScanner

The accuracy of measuring the outer shape of Scots pine (Pinus sylvestris L.) saw logs with an X-ray LogScanner has been compared with the accuracy of using a 2-axis optical scanner, a S-axis optical scanner and an ideal 3-D optical scanner. The different scanners were simulated using computed tomography (CT) data from the Swedish Stem Bank. The outer shape of 60 saw logs was measured every third centimeter. The error attributable to bark when using optical scanners was simulated separately. The results From the simulations showed that when measuring the outer shape on bark, the X-ray LogScanner facilitated measurement of the minimum shadow diameter with the same accuracy as with a 3-D optical scanner. The results also showed that the potential of combining the X-ray LogScanner with a 3-D optical scanner should be investigated.