自動化金屬偵測與影像融合方法之CT影像金屬偽影消除

電腦斷層掃描因為金屬植入物所造成的金屬偽影降低了影像品質且限制了相關應用。標準金屬偽影消除方法是使用周圍未受金屬影響的投影數據來插補替換受金屬影響的投影數據，但是處理後的影像品質往往不僅下降，且容易產生新的偽影。故為了改善這些缺點，本研究提出自動化金屬偵測與影像融合方法，該方法基於四個步驟：(1)自動化金屬偵測使用經過移動平均法濾波的直方圖來得到適當的門檻值來分割影像中的金屬部位，(2)利用線性插補和邊緣保留濾波器產生預處理影像，(3)權重性插補被用來修正遺失的投影數據來獲得具可識度的金屬部分，(4)影像融合方法融合原始投影數據和預處理影像投影數據進行斜坡權重接合方法與金屬區域差值線性插捕方法後重建的兩張影像建立最終影像。最後，兩組假體實驗和六組臨床實驗證明了本研究提出的方法能夠有效地消除金屬偽影且提升影像品質。與其他方法的比較顯示出了本研究提出的方法不僅大幅地改善金屬偽影，且更有效率地處理相關運算，以達到醫學上的需求。

關鍵字

自動化金屬偵測；金屬偽影消除；電腦斷層掃描；權重性插補；影像融合方法

並列摘要

The purpose of this thesis is to develop a metal artifacts elimination algorithm and applied on the digital dental category application. The metal artifacts caused by metal implants have great impacts on the image quality and limit the applications of computed tomography. The standard method used to reduce these metal artifacts often consists of interpolating method, but that will result on the losing of image quality and produce new artifacts at the same time. To overcome these drawbacks, this paper proposes a new strategy based on a four process method: (1)Automatic metal detection using histogram filtered by moving average filter to segmentations metal from the computer tomography images. (2)Generating the preprocessed image by means of linear interpolation and an edge-preserving blur filter. (3)The weighted interpolation are used to repair missing projection data of metal part. (4) Image fusion method is applied to build the final image from two image reconstructed by processed projection data by ramp weighted combination method and difference data linear interpolated in the metal region method. Finally, 2 phantom images test and 6 clinical images are applied to invalidate that the proposed method can reduce metal artifacts and enhance image quality effectively. A comparison with other methods demonstrates that the proposed method performs better in metal artifact reduction, and our processed method processing efficiency is better than metal deletion technique (MDT).

並列關鍵字

Image fusion method ； Weighted interpolation ； Automatic metal detection ； Metal artifact reduction ； Computed tomography

參考文獻

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自動化金屬偵測與影像融合方法之CT影像金屬偽影消除

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