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題 名 | 多路徑超音波斷面影像技術評估柳杉人造孔洞之研究=Evaluation of Artificial Holes in Cryptomeria Japonica by Ultrasonic Tomography Technique |
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作 者 | 高毓謙; 林振榮; 林達德; 蔡明哲; | 書刊名 | 國立臺灣大學生物資源暨農學院實驗林研究報告 |
卷 期 | 19:3=249 民94.09 |
頁 次 | 頁239-250 |
分類號 | 436.18 |
關鍵詞 | 多路徑超音波斷面影像技術; 人造孔洞; 傳遞時間; Ultrasonic tomography technique; Artificial holes; Propagation time; |
語 文 | 中文(Chinese) |
中文摘要 | 本研究應用多路程超音波斷面影像技術,評估柳杉圓盤內部之不同大小人造孔洞。研究中使用SYLVATEST-DUO(上標 ®)超音波儀檢測,以人工逐次挖鑿柳杉圓盤中央孔洞模擬不同心腐程度,探討不同路程超音波速度及相對速度損失率與孔洞直徑關係,及使用超音波傳遞時間比值和2D分析圖平均速度與孔洞直徑比值、孔洞殘餘比值、孔洞面積比值進行討論,結果顯示圓中央孔洞直徑殘餘比值與超音波速度在Type D (180º)有最高的相關性,其R^2值可達0.94,依次為Type C(135°)>Type B (90°)>Type A(45º)。在超音波2D斷面影像圖形中發現能顯示出孔洞位置與大小,在圓盤孔洞部分明顯與周圍顏色有差異存在,亦代表著超音波速度的差異,相對的圓盤材質狀況也有差異,在孔洞/圓盤斷面積比值約2.7%以上時,皆能顯示出圓盤內部孔洞位置,與以往之研究比較,已提升評估之準確性,可以應用做為評估林木樹幹心腐程度之參考,配合VTA (Visual Tree Assessment)法可做為林木危險度評估之依據。 |
英文摘要 | The purpose of this study was to investigate artificial holes in the cross section of Cryptomeria japonica by using ultrasonic tomography technique. The ultrasonic instrument SYLVATEST-DUO(superscript ®) and the trunk section of Cryptomeria japonica were employed. In order to simulate different degrees of the core decay, chiseling on the central area of trunk section was done by hand and then the ultrasonic velocities of various measured directions were investigated. The relationships among different values of ultrasonic velocities, the relative velocity drop, and the diameter of the diameter of the chiseled hole were analyzed. Moreover, we discussed the relationships among the ratio of propagation time in the 90° direction to radial (180°) direction, the average velocity of ultrasonic tomography, the ratio of the hole/section diameter, the ratio of the hole remnant, and the ratio of the hole/section area. The highest correlation coefficient was found between the ratio of central hole remnant and the ultrasonic velocity in route D (two adjacent measured points) with R^2 value up to 0.94. The order according to correlation coefficient was as followed: route C (two-point interval between two measured points), route B (one-point interval between two measured points), and route A (two measured point are adjacent to each other). It was also found that the location and the size of the hole in the tree trunk section could be detected by the ultrasonic tomography. The color difference between hole area and its surrounding area was obvious after ultrasonic tomography analysis. When the ratio of hole area to section area was above 2.7%, the hole was able to be detected by ultrasonic tomography. The results could be applied for the evaluation of trunk core decay, and could be used as a basis for the visual tree assessment. |
本系統中英文摘要資訊取自各篇刊載內容。