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首页> 外文会议>International Symposium on Nondestructive Testing of Wood; 20000913-20000915; Sopron; HU >Measurement of Spiral Grain with Computed Tomography compared with pattern on boards
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Measurement of Spiral Grain with Computed Tomography compared with pattern on boards

机译：用计算机断层扫描技术与板图测量螺旋晶粒度

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Spiral grain is a wood feature that affects the shape of the sawn timber. Boards sawn from logs with large spiral grain have a great tendency to twist when the moisture content changes. In practice in sawmills the spiral grain in logs is judged manually. For research purposes the spiral grain in stems and logs is normally measured by destructive methods. In this study the spiral grain of the stems was measured non-destructively with a CT scanner (Computed Tomography). Nine Scots pine (Pimis silvestris) logs from Sweden were scanned with a CT scanner with one cross-sectional scan every 10mm along the stem. From the stack of CT-images, concentric surfaces at different distances from the pith were reconstructed. In these concentric-surface images, which show different internal features of the log, the spiral grain angle was measured at different distances from the pith and at different heights in the log. These measurements of the spiral grain made with CT-images were compered with measurements made on 18 boards sawn from the same logs. Finally the results from the destructive method were compared with the results from the analysis of the CT-images. The measurements on the boards were compared in pairs with the same radial and approximately the same height position in each pair. The correlation (r) between the two methods was 0.85 and R~2 was 0.73. It was concluded that there is a very good correlation between the spiral grain angle measured non-destructively with a CT scanner and a pattern observed on the boards.
机译：螺旋纹是影响锯材形状的木材特征。当水分含量变化时，用大螺旋纹的原木锯切的木板容易扭曲。实际上，在锯木厂中，手动判断原木中的螺旋纹。出于研究目的，通常通过破坏性方法测量茎和原木中的螺旋纹。在这项研究中，使用CT扫描仪（计算机断层扫描）对茎的螺旋纹进行了无损测量。用一台CT扫描仪扫描了瑞典的9根苏格兰松（Pimis silvestris）原木，沿茎每10毫米进行一次横截面扫描。从一堆CT图像中，重建了距髓距不同距离的同心表面。在这些同心表面图像中，它们显示了圆木的不同内部特征，在距木髓不同距离和圆木中不同高度处测量了螺旋晶粒角。用CT图像对螺旋纹的这些测量结果与在从相同原木锯切的18块木板上进行的测量结果进行了比较。最后，将破坏性方法的结果与CT图像分析的结果进行比较。将板上的测量值成对比较，每对中的径向位置和高度位置大致相同。两种方法之间的相关性（r）为0.85，R〜2为0.73。结论是，用CT扫描仪无损测量的螺旋晶粒角与在板上观察到的图案之间有很好的相关性。

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