Crack Severity Classification from Timber Cross-Sectional Images Using Convolutional Neural Network

Cedar and cypress used for wooden construction have high moisture content after harvesting. To be used as building materials, they must undergo high-temperature drying. However, this process causes internal cracks that are invisible on the outer surface. These defects are serious because they reduce...

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Main Authors: Shigeru Kato, Naoki Wada, Kazuki Shiogai, Takashi Tamaki, Tomomichi Kagawa, Renon Toyosaki, Hajime Nobuhara
Format: Article
Language:English
Published: MDPI AG 2023-01-01
Series:Applied Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3417/13/3/1280
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author Shigeru Kato
Naoki Wada
Kazuki Shiogai
Takashi Tamaki
Tomomichi Kagawa
Renon Toyosaki
Hajime Nobuhara
author_facet Shigeru Kato
Naoki Wada
Kazuki Shiogai
Takashi Tamaki
Tomomichi Kagawa
Renon Toyosaki
Hajime Nobuhara
author_sort Shigeru Kato
collection DOAJ
description Cedar and cypress used for wooden construction have high moisture content after harvesting. To be used as building materials, they must undergo high-temperature drying. However, this process causes internal cracks that are invisible on the outer surface. These defects are serious because they reduce the strength of the timber, i.e., the buckling strength and joint durability. Therefore, the severity of internal cracks should be evaluated. A square timber was cut at an arbitrary position and assessed based on the length, thickness, and shape of the cracks in the cross-section; however, this process is time-consuming and labor-intensive. Therefore, we used a convolutional neural network (CNN) to automatically evaluate the severity of cracks from cross-sectional timber images. Previously, we used silver-painted images of cross-sections so that the cracks are easier to observe; however, this task was burdensome. Hence, in this study, we attempted to classify crack severity using ResNet (Residual Neural Network) from unpainted images. First, ResNet50 was employed and trained with supervised data to classify the crack severity level. The classification accuracy was then evaluated using test images (not used for training) and reached 86.67%. In conclusion, we confirmed that the proposed CNN could evaluate cross-sectional cracks on behalf of humans.
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spelling doaj.art-29c8280699a049bea86d4a5ec54a176b2023-11-16T16:03:09ZengMDPI AGApplied Sciences2076-34172023-01-01133128010.3390/app13031280Crack Severity Classification from Timber Cross-Sectional Images Using Convolutional Neural NetworkShigeru Kato0Naoki Wada1Kazuki Shiogai2Takashi Tamaki3Tomomichi Kagawa4Renon Toyosaki5Hajime Nobuhara6National Institute of Technology, Niihama College, 7-1 Yagumo-cho, Niihama 792-8580, JapanNational Institute of Technology, Niihama College, 7-1 Yagumo-cho, Niihama 792-8580, JapanNational Institute of Technology, Niihama College, 7-1 Yagumo-cho, Niihama 792-8580, JapanEhime Prefectural Forestry Research Center, 2-280-38 Sugou, Kumakougen-cho 792-1205, JapanNational Institute of Technology, Niihama College, 7-1 Yagumo-cho, Niihama 792-8580, JapanNational Institute of Technology, Niihama College, 7-1 Yagumo-cho, Niihama 792-8580, JapanDepartment of Intelligent Interaction Technologies, Graduate School of Systems and Information Engineering, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8573, JapanCedar and cypress used for wooden construction have high moisture content after harvesting. To be used as building materials, they must undergo high-temperature drying. However, this process causes internal cracks that are invisible on the outer surface. These defects are serious because they reduce the strength of the timber, i.e., the buckling strength and joint durability. Therefore, the severity of internal cracks should be evaluated. A square timber was cut at an arbitrary position and assessed based on the length, thickness, and shape of the cracks in the cross-section; however, this process is time-consuming and labor-intensive. Therefore, we used a convolutional neural network (CNN) to automatically evaluate the severity of cracks from cross-sectional timber images. Previously, we used silver-painted images of cross-sections so that the cracks are easier to observe; however, this task was burdensome. Hence, in this study, we attempted to classify crack severity using ResNet (Residual Neural Network) from unpainted images. First, ResNet50 was employed and trained with supervised data to classify the crack severity level. The classification accuracy was then evaluated using test images (not used for training) and reached 86.67%. In conclusion, we confirmed that the proposed CNN could evaluate cross-sectional cracks on behalf of humans.https://www.mdpi.com/2076-3417/13/3/1280timbercrackconvolutional neural networkResNethuman fuzziness
spellingShingle Shigeru Kato
Naoki Wada
Kazuki Shiogai
Takashi Tamaki
Tomomichi Kagawa
Renon Toyosaki
Hajime Nobuhara
Crack Severity Classification from Timber Cross-Sectional Images Using Convolutional Neural Network
Applied Sciences
timber
crack
convolutional neural network
ResNet
human fuzziness
title Crack Severity Classification from Timber Cross-Sectional Images Using Convolutional Neural Network
title_full Crack Severity Classification from Timber Cross-Sectional Images Using Convolutional Neural Network
title_fullStr Crack Severity Classification from Timber Cross-Sectional Images Using Convolutional Neural Network
title_full_unstemmed Crack Severity Classification from Timber Cross-Sectional Images Using Convolutional Neural Network
title_short Crack Severity Classification from Timber Cross-Sectional Images Using Convolutional Neural Network
title_sort crack severity classification from timber cross sectional images using convolutional neural network
topic timber
crack
convolutional neural network
ResNet
human fuzziness
url https://www.mdpi.com/2076-3417/13/3/1280
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AT tomomichikagawa crackseverityclassificationfromtimbercrosssectionalimagesusingconvolutionalneuralnetwork
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