本研究旨在結合通用攝影機及質點影像量測法（Particle Image Velocimetry，簡稱PIV）建構一套通用型影像量測系統(General Particle Image Velocimetry，簡稱GPIV)用於分析流場之可行性及準確性，利用疊合方法改善量測解析度不足的問題，並將此系統於設有圓柱構造物之渠道實際操作量測。

　　實驗中將連續式雷射光打在量測平面，使用鋁粉作為追蹤質點，並利用一般通用型數位攝影機擷取雷射光頁之影像，經過數位化、尺度校正及濾波處理，由流場定量化程式經相關分析，得二維量測面瞬時流速向量場，取1sec時間內各組連續二維瞬時流速向量場之平均，即可獲得經1sec時間平均之二維流速分佈圖。

　　經本研究得知，GPIV於流況均勻之流場擷取不同位置的連續影像進行流速分析，再以疊合方法將不同區域的分析結果結合，可得到解析度較大的量測結果。分析過程中難免產生誤判的速度向量，經使用中值濾波處理流場後，可使量測結果更為良好。實驗中影像校正誤差約為2.5﹪，無結構物量測之流速剖面與對數律（log-law）公式之差異在15﹪內，使用疊合方法確實可增加流場量測解析度，觀察到使用較大分析區量測時被平均化的現象，證實GPIV系統用於二維流場量測，為一具可行性且費用較低之量測技術。

　This study establish General particle image velocimetry system（GPIV） which combine general camera and Particle image velocimetry （PIV）to analyze flow filed and test it’s accuracy and feasibility. The congruence method is designed to improve spatial resolution. After setting up GPIV system, experimental investigations are performed in a straight open channel with circular cylinder.

　In experiment, a continuous wave laser is used to illuminate the measurement plane and the flow is seeded with aluminum particles. Digital camera is used to capture the images of laser sheet. After digitalize processing, scale correction and filter processing, two-dimension instantaneous velocity fields are determined by cross-correlation analysis. We select 1 sec time-average for continuous two-dimension instantaneous velocity fields.

　Through this research we can know, the images we capture by GPIV system in steady flow at different measurement places. After using congruence method to analysis results, we can get higher spatial resolution. But it’s hard to avoid miss judging for velocity vectors. We can get better effect after using Medium filter to deal with error vectors. In experiment, spatial scale correction errors are about 2.5﹪,the diversities of velocity profiles witch compare with log-law curve are within 15﹪.The congruence method can indeed improve the measure resolution and observe flow conditions which equalize by bigger integration area. For those reasons, it proves using GPIV system to analyze two-dimension flow fields is a feasibility and economical measurement technique.

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