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題 名 | Feature Curves Based Cephalometric Superimposition=應用特徵曲線作測顱術之影像對位 |
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作 者 | 陳彥廷; 鄭國順; 簡明隆; 劉佳觀; | 書刊名 | Journal of Medical and Biological Engineering |
卷 期 | 20:4 2000.12[民89.12] |
頁 次 | 頁211-218 |
分類號 | 414.93 |
關鍵詞 | 特徵曲線擬和; 測顱疊印; 界標; 影像處理; Feature curve matching; Cephalometric superimposition; Landmark; Image processing; |
語 文 | 英文(English) |
中文摘要 | 測顱攝影片疊印是臨床上評估齒顎矯正或手術成效的重要方法之一,包括三個區域疊印:顱底,上顎和下顎。目前都是醫師以手動方式重疊手術前後或矯正前後所拍攝兩張測顱攝影片,疊印後經由分析與計算,評估矯正或手術的成效。由於頭顱解剖結構複雜與生長因素的影響,加上X光片拍攝條件如曝光時間之不同,導致測顱攝影片上的特徵不易辨識,因此以人工方式辨識在兩張X光片上的相同特徵,經常會有困難。即使找到相同特徵,也很可能由於兩者的形態因矯正,治療手術或生長而改變,無法完全重疊;因此醫師係以主觀的方式判定疊印的最佳位置,不同醫師所估算結果將因上述原因而造成極大的差異。本研究主要目的為將疊印的過程電腦化,並提供量化參數以供參考。本系統主要包括三部分:(1)影像資料輸入及校準-影像是經由CCD攝影機拍攝而載入電腦;(2)特徵線段擷取-包括兩個區域,其一為顱底曲線是藉由最佳方向性偵測子及Hough轉換求得。另一為下顎曲線是由Laplacian of Gaussian及Grouping求得;(3)依各種疊印方法之法則自動執行疊印-使用的方法有兩種,Cluster space和相關係數。研究的結果,可以自動找出顱底曲線和下顎外圍輪廓曲線及自動疊印;上顎的特徵線段則以相關係數法直接疊印。整個處理過程約5-6分鐘,較醫師以手動須要30~40分鐘節省許多時間。顱底曲線求得的精確性是0.312cm,下顎是0.005cm。整個疊印過程與醫師做比較,其差異性在顱底是0.95cm,上顎是0.98cm,下顎是1.26cm。 |
英文摘要 | The analysis of the spatial changes of the craniofacial structures for orthodontic treatment or surgery always relies on the superimposition of cephalometric tracings taken at different times. The errors in the manual measurement of superimposition may be arisen from the bad cephalogram quality, the facial growth, and the orthodontist's experience. In this paper, the computerized superimposition is developed for alleviating the problems mentioned above. This procedure contains three parts: 1. To digitize and calibrate the cephalogram through the CCD camera; 2. To extract the feature curves for the cranial base using the best oriental edge detector and Hough transform, and for the mandible using the Laplacian of Gaussian and grouping; and 3. To automate the superimposition based on the clinically available procedure and finally to display the associated results. The complete procedure typically takes 5 to 6 minutes of computation. The precision for the cranial base superimposition is about 0.312cm, and the mandible about 0.005cm. The difference between the superimpositions of the proposed system and the manual measurement is about 0.95cm in the cranial base, 0.98cm in the maxillary, and 1.26cm in the mandible. |
本系統中英文摘要資訊取自各篇刊載內容。