Patent ID: 7149633

Claim:
A method of estimating the displaced size of a knot in a lumber piece comprising the steps of: a) providing a first radiation source on a first side of a flow path; b) providing a first radiation sensor on an opposite second side of said flow path and cooperating with said first radiation source; c) translating the lumber piece downstream along said flow path and between said first radiation source and said first radiation sensor while simultaneously irradiating the lumber piece with radiation from said first radiation source whereby said radiation is attenuated by said lumber piece; d) collecting a set of first radiation intensity data from said first radiation sensor as the lumber piece is irradiated as it is translated between said first radiation source and said first sensor; e) processing said set of first radiation intensity data to sum said first radiation intensity data and to provide radiation intensity profiles transversely of the flow path direction of said flow path and corresponding density profiles transversely of said flow path direction; f) mapping said density profiles to model a first set of three dimensional density profiles of the lumber piece; g) processing said first radiation intensity data to determine a clear wood density threshold value for the lumber piece and a maximum density value of said density profiles; and h) computing a ratio of the summed density profile values to the summed maximum density values for said density profiles and multiplying said ratio with the transverse width of the lumber piece.