Using an embedded-processor camera for surface scanning of unplaned hardwood lumber

Abstract

The initial breakdown of hardwood logs into lumber produces boards with rough (unplanned) surfaces. Because hardwood lumber value is determined by board size and by the percentage of defect-free area (lumber grade), sawmills remove some wood from the edges and/or ends of a board prior to sale. The overall goal of this research project is to develop a prototype scanning system that can automatically identify important defects (knots, wane, and voids) on rough hardwood lumber and can recommend optimal cuts to achieve maximum lumber value for each board. The first step for inspection system development is to integrate off-the-shelf scanning hardware components with in-house developed software to capture high-quality board images. Board illumination is realized by three, 650 mm lasers that cast lines across the width of a board as it moves longitudinally on a conveyor. A matrix array picture processor camera was selected for image capture. It contains an array of 256×256 photodiodes, where each row is address...