指紋辨識是現今應用最為廣泛的生物辨識技術。國際標準組織(ISO)於2005年完成制定並公告指紋特徵檔的標準格式(ISO19794-2)。定義指紋特徵點為指紋紋路的端點與分歧點。指紋特徵點的資訊包含特徵點座標、方向和型態。

指紋辨識系統是透過分析指紋影像特性達到身分辨識的系統。使用者經由手指按壓指紋讀取機取得指紋影像。藉由影像處理與特徵抽取的程序取得指紋特徵模板。將該特徵模板與事先於指紋建檔程序中建檔之指紋特徵資料庫，進行特徵比對並以相似度分數作為身分之判定依據。因此，指紋建檔程序是指紋辨識系統中重要的一環。

本研究提出了一個指紋特徵合成應用於指紋辨識系統之多次按壓建檔程序。探討手指按壓於指紋讀取機取得指紋影像的各種變動(按壓面積、按壓位置、按壓重疊範圍、按壓壓力)因素，對於指紋辨識系統之影響。此指紋建檔程序分為三個階段，第一階段是應用圖形理論整合指紋特徵相互比對的結果，並將成對特徵點之座標平均以建構交集區域的指紋特徵。第二階段是藉由描繪指紋的有效範圍，並且結合特徵點成對資訊與特徵點於整體指紋有效範圍之位置分佈，作為特徵點的正確性之判斷依據，進一步將特徵點分為四個群組。第三階段是針對聯集區域，以區域性特徵比對的方式尋找可恢復性的特徵點。克服手指按壓壓力不均勻而產生的特徵點座標偏移現象。最後，藉由指紋特徵之信心度為門檻值加入高正確性特徵點以更新交集區域的特徵點。最終的指紋特徵檔是由交集區域的指紋特徵、聯集區域之未重疊特徵點和可恢復性的特徵點所構成。

本研究採用三組指紋資料庫，依序是國立清華大學學生資料庫(A)、(B)以及印度國小學生資料庫。根據實驗結果，在不同的指紋讀取機、三種指紋按壓模式以及影像品質不佳的指紋資料庫，本研究所提出之指紋建檔程序皆能有效改善系統辨識率平均達45%至65%，其EER為0.2%至1.2%。

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