the point or region of injection, a defect such as a knot in the timber, being...http://www.google.com/patents/US3976384?utm_source=gb-gplus-sharePatent US3976384 - Method and apparatus for detecting timber defectsAdvanced Patent SearchPublication numberUS3976384 APublication typeGrantApplication numberUS 05/541,573Publication dateAug 24, 1976Filing dateJan 16, 1975Priority dateJan 18, 1974Also pu