Automated grading and defect detection: A review

In a plant that manufactures wood products, such as lumber, dimension stock, or veneer sheets, inspection of the products is a necessary part of the production process. At present, most inspection tasks are carried out manually. However, because of the high speed with which it is necessary to perform the operation and the stress involved, attempts have been made to automate this grading process. This paper surveys research in the field of automatic inspection of wood, particularly focusing on computer vision techniques. The methods are put into an Automated Visual Inspection framework, which is subdivided into commonly used modules for image acquisition, image enhancement, image subdivision, feature extraction, and classification.