Abstract: A method for determining the wood/bark ratio from a flow of wood material, in which the flow is illuminated in a non-flashing manner, scanned along a transverse line with a video camera with at least three channels, the line image corresponding to the line is digitalized into pixels each of which comprise intensity information, the intensity classes corresponding to the wood and the bark are determined in each channel and the pixels belonging to each class are calculated with the help of their intensity-information, and the wood/bark ratio is determined by the number of pixels situated in the different intensity classes. The dynamics of each channel are at least 10, most preferably 12 bit.

Abstract: A method and arrangement for measuring the moisture content of a flow of wood chips, through which collimated gamma radiation is directed attenuation of which in the flow of wood chips is measured. The flow of wood chips is shaped by transporting it on a trough-shaped conveyor in such a way that the length of a ray can be determined. The moisture content can be calculated on the basis of the proportion of gamma radiation passing through the flow of wood chips and the flow's thickness, as well as on the basis of the previously determined air content of the flow of wood chips.

Abstract: An on-line method for determining the wood-bark ratio in a flow of material containing both wood and bark includes illuminating the flow of material and scanning using a CCD camera, by means of which 30-300 image pixels/cm are obtained in the transverse direction of the flow of material. Narrow transverse groups of 1-20 adjacent pixels, in which the brightness of the pixels deviates from a preset criterium are filtered out of the transverse group of pixels and the calculation of the wood-bark ratio of the photographs takes place without these narrow groups.