The original gray level image was changed into the macroscopical drawing information by pre-processing, threshold selection, image bivalency, edge detection and contour extraction and segmentation.
对原始数字图像实施预处理、二值化、轮廓提取及细化等处理后，将图像信息转变成宏观图形信息。
Edge detection is one of the basic pre processing methods in digital image processing and computer vision. It is one of the most important algorithms making the processing going further.
边缘检测是数字图像处理中的基本预处理方法之一，由于利用检测出来的图像边缘可以对图像做进一步的处理，因此它是图像处理中的基础算法。
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