通過攝像頭TWAIN 接口將百分表圖像提取出來后，使用區域分割的方法，將儀表表盤
各個部分特征提取出來：采用消影法獲得指針，Ostu 的類間方差方法分割二值化指針，Hough 變換獲得指針邊緣直線進而得到表盤中心，并利用百分表的特征將數字與刻度分離并分別進 行標記與識別。通過實驗可以看到，這種基于數字、刻度與指針進行綜合識別的方法，具有良好的識別效果。
關鍵詞：百分表； 圖像識別； 霍夫變換；最大類間方差
Abstract: After detection of the certigratemeter by camera through TWAIN interface, every partof the meter can be obtained by region segmentation: achieve points by shadow elimination, segment the binary pointers by the way of criterion of maximum between-cluster which is put forward by Ostu, acquire the edge line of the points and center by Hough transform , and then stamp and recognise them after separating the numbers and grates according to the image character of Dial Indicator. Finally, the experiment shows that the method of synthetical recognition to numbers, grates, and pointers is very feasible.
Keyword: Dial Indicator, Image Recognition，Hough transform, criterion of maximum
between-cluster