In Vivo Observation of the Blood Flow in Human Capillaries under Finger Nailfold

游 漢輝, 易 政男, 李 孝貽, 黎 耀強, Hen-Hong Chang

Research output: Contribution to journalJournal Article peer-review


我們發展出一個系統去拍攝出甲襞微循環的影像並計算出微血管中的血流速度。這個系統主要包括一個顯微鏡及一個數位攝影機。由這個組合去把微循環的動態影像記錄下來。進而利用這些動態影像去推算在微血管中之血流速度。我們發覺如果在此系統的光源前加上一個綠色的濾光片,它就會把組織的血紅色過濾掉,因而所拍攝得到的微循環圖片的影像對比度會大大改善。另外,我們發覺必須在皮膚表面塗抹上一層合適的介質液(matching oil),才會降低皮膚表層粗糙面所造成之嚴重散射,才會得到清晰的影像。至於血流的計算方法大致上可分兩步驟,第一,使用互相關函數法(cross-correlation)去尋出動態影像中每一張靜態影像和第一張影像的位移的大小,然後根據這個位移量,把這些影像移回它該顯現的位置。經過這樣的處理,我們得到一連串很不錯的穩定影像。第二,我們在微血管的上下游放置兩個窗口,由這兩個窗口的灰階變化去計算出血液流速。我們計算出的結果為,對一個正常的健康者來說,他們的微循環流速大約為每秒100μm。最後,我們這個方法的特色為可以明確地指出所量測的血流在血管中的位置。
A setup for seeing the capillaries just under the finger nailfold of a human being has been developed. The setup consists of a microscope and a CCD camera. We found that by using an interference filter to filter out the red color, we can obtain a good picture of the capillaries. Equally important for obtaining a good picture, we found that some appropriate matching oil must be applied on the skin surface. Before we calculate the velocity of the blood, we proposed a method to stabilize the raw pictures obtained from the CCD camera because the pictures vibrate seriously due to the involuntary motion of human beings. The feature of this method is that it can pinpoint the capillary in which the blood velocity is measured.
Original languageAmerican English
Pages (from-to)91-96
JournalJournal of Medical and Biological Engineering
Issue number2
StatePublished - 2002


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