Method and device for determination of desired middle line of a cylindrical object such as a log

Claim 1

A procedure for determining an optimum axis or centerline of a generally cylindrical object such as a log, for further processing in a working machine such as a lathe, said procedure including the steps of: (a) fixing the object to be worked upon in a positioner operating in connection with the said working machine; (b) recording the diameter of the object along the length of the object with at least one image producing device, such as a camera, from different angles about a longitudinal axis of the object; (c) determining the size of the inscribed, largest possible essentially rectangular geometric figures obtained from each projection of the object produced at the corresponding angle; (d) storing the size of the inscribed, largest possible essentially rectangular geometric figures, obtained from each projection of the object produced at the corresponding viewing angle, in the memory of a computer; (e) calculating with the aid of said computer the smallest of the said figures and computing the intersecting line between this figure and another figure stored from a projection recorded at a predetermined angle relative to the angle at which the said smallest figure was recorded, and regarding said intersecting line as the optimum centerline of the object; (f) computing the location of said intersecting line in relation to the centerline of said positioner and transmitting the net distance components of any required shifting of the object to fixing elements of the positioner, so that the centerline of said positioner eventually coincides with said intersecting line.