Abstract: The object of the invention is a method and apparatus for measuring the characteristic quantities, such as e.g., the length, diameter, volume, and defects of a log (1) or similar in which method the log (1) is moved at a known speed past a photographing station. The photographing station consists of at least one plane of light (4.1) that transects the direction of travel of the log and a video camera (3) set at a fixed angle (a) to this, and a computer apparatus (6), which is arranged to calculate and collect sequential images of a group of surface points (x.sub.l, y.sub.l, z.sub.l ; . . . ; x.sub.n, y.sub.n, z.sub.n) of a three-dimensional model depicting the surface of the log as the log moves through the plane of light, in which the coordinates of each point are calculated with the aid of the geometry of the photography. The log (1) is transported transversely to the direction of the conveyor, the log then traveling along an imagined plane, while the plane of light (4.

Abstract: The object of the invention is a stack measurement method and equipment to measure especially the timber volume and other dimensions, in which method the external dimensions of the stack, and the average diameter and length of the logs are measured, from which the timber volume is calculated. The method includes the following stages: a beam of light is set transversely around the stack; the beam of light is photographed at an angle from both in front and behind, from both sides and from on top of the stack; the location of the beam is measured from the video image; the curves depicting the surface of the logs are recognized and differentiated from the image of the line; the diameter of the outer logs at the point of measurement is calculated from the curves; measurement is carried out at regular intervals over the entire length of the stack, when the lengths of the outer logs are obtained; the dimensions of the outermost logs are calculated, and with their aid the average diameter and length.