Optical scanning device for lumber
AssigneeUnited Industrial Products, Ltd.
InventorStuart G. Moore
Life of this patent
Estimating the term…
Abstract
The present invention relates to an optical scanning device for use in sawmills, to determine the severity and location of surface defects on lumber, for the purpose of grading and trimming, having a plurality of optical scanning means mounted to a frame and positioned above lumber transport means. The scanning means are adapted to scan at least one face of a predetermined segment of each board, and comprise a lens, means to convert an image resolved in the lens into electronic signals and means to transmit said signals to signal processing means adapted to assess surface defects on the board and determine a lumber grade of each board. The device may include means for rotating each board about its longitudinal axis to sequentially expose the longitudinal faces thereof to the scanning means.
Claims26
A lumber inspection device for detecting surface features on boards, said boards each having upper, lower and side longitudinal faces and cross sectional dimensions and at least some of said boards having surface defects on said faces, said defects each having a size, shape and location, said device comprising:
- a frame;
- an array of optical scanning means mounted to said frame;
- lumber transport means comprising a conveyor for conveying said boards, said conveyor adapted to transport boards from a rearward portion of said conveyor to a forward portion of said conveyor, with the upper longitudinal faces of said boards facing upwardly when conveyed along said rearward portion;
- and board rotation means positioned between said rearward and forward portions of said conveyor, said rotation means adapted to engage each board as said board is conveyed along said conveyor, rotate said board by 180 degrees such that its lower longitudinal face faces upwardly and redeposit said board on said conveyor, wherein the upper,lower and side longitudinal faces are sequentially exposed to said optical scanning means wherein said optical scanning means are positioned above said conveyor, and wherein said scanning means are adapted to scan a predetermined segment of each board each of said segments having a position within said board, said scanning means comprising a lens and signal processing means to convert an image resolved in said lens into electronic signals and assess surface defects on the board and transmit said information to a central processing unit to determine a lumber grade of each board.
A scanning means for assembly within a lumber inspection device for the inspection of a board having surface defects, said surface defects each having a size, shape and location, said scanning means comprising a housing mountable to said lumber inspection device, said housing supporting therein a light source and an area scanning unit, wherein said scanning unit comprises a lens adapted to view in a single image two adjacent faces of a discrete segment of said board comprising a portion of said board less than the entire length thereof, means to convert the image into electronic signals, and signal processing means to process said electronic signals, said signal processing means comprising means to identify the shape, location and size of said surface defects, means to perform thresholding analysis thereon, and means to transmit resulting signals to a central signal processing unit, said scanning means adapted to independently scan said discrete segment and to cooperate with other like scanning means to determine a lumber grade and optimal trim for said board.
A method for inspecting lumber for surface defects, comprising the steps of positioning a board on lumber transport means, said boards each having upper, lower and side longitudinal faces and cross sectional dimensions and at least some of said boards having surface defects on said faces, said defects each having a size, shape and location, transporting said board through a frame by said transport means, scanning said upper face and a first side face of said board by means of a first optical scanning means positioned on said frame above said board, rotating said board such that its lower face faces upwardly, and scanning said lower face and a second side face of said board with a second optical scanning means positioned above said board and mounted on said frame, said first and second scanning means each adapted to scan a predetermined segment of said board, said segment having a position within said board, said first and second scanning means being adapted to receive visual information from the surface of said board and to convert the visual information received thereby into electronic signals, said signals being conveyed to signal processing means adapted to assess the position and size of surface defects on said board, to perform thresholding analysis in respect of said surface defects, to compare said surface defects with defect size, type and location rules imposed by predetermined grading rules, and to indicate a grade of said segment of the board and transmit said information to a central processing unit adapted to receive similar information from like scanning means and assess an overall grade and optimum trim for said board.
Dependencies are inferred from the claim text.