Real Time Defect Detection for Timber Industry with Deep Neural Networks

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Journal Title

Journal ISSN

Volume Title

Perustieteiden korkeakoulu | Master's thesis

Date

2020-08-18

Department

Major/Subject

Machine Learning, Data Science and Artificial Intelligence

Mcode

SCI3044

Degree programme

Master’s Programme in Computer, Communication and Information Sciences

Language

en

Pages

50+1

Series

Abstract

Automatic timber grading requires fast, accurate and consistent defect detection to support downstream solution optimization. Traditional image processing techniques based on handcrafted feature descriptors are sensitive to scanning disturbance and often require extensive domain knowledge to develop. In this master’s thesis, we develop a method to perform accurate wood defect detection in real time based on deep neural network models. We address the problem of imbalanced defect distribution in the dataset by combining type aggregation and effective sampling, such that infrequent defects can be detected well despite inadequate annotations. On the production dataset provided by FinScan Oy, our model achieved a mean average precision of 11.63% for all 12 different wood defects and an average precision of 42.27% for dead knots, which are the most influential defects in final grading. On the RTX 2080Ti GPU, the model runs at 25 frames per second which brings a potential throughput of 250 boards per minute for the saw line.

Description

Supervisor

Ilin, Alexander

Thesis advisor

Eskola, Kalle

Keywords

deep learning, automatic timber grading, convolutional neural networks, wood defect detection, effective sampling, computer vision

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