针对大规模空间封闭图形的高效识别，考虑与识别有关的各个阶段，给出基于转向法的空间封闭图形识别总体方案。
Aiming at efficient recognition of large-scale closed space graph, an overall scheme of recognition based on turning is given, considering the various stages related to recognition.
结果证明：基于图元表示法对常见手绘几何图形识别速度快、准确率高；
The results prove that:our system has a high speed and accuracy.
圆弧和圆是工程图形中的重要图元，已有多种识别算法，可分为两种：逼近法和直接法。
The scanning input and recognition of engineering drawings is a key step in CAD, and is to reuse lots of engineering drawings.
圆弧和圆是工程图形中的重要图元，已有多种识别算法，可分为两种：逼近法和直接法。
The scanning input and recognition of engineering drawings is a key step in CAD, and is to reuse lots of engineering drawings.
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