在线手绘平面立体投影图的端点融合

Endpoint Fusing Method for Projection Drawing of Online Freehand Sketched Polyhedrons

端点融合是手绘草图规整过程中尤为重要的一个环节,其对于草图的最终规整结果也影响甚大.针对现有手绘平面立体投影图的端点融合方法的不足,提出一种基于角度直方图的融合方法.首先根据拟合后草图笔画的角度信息得到相应的角度直方图,并对笔画进行平行处理;然后利用容差圆判定聚类笔画,得到若干组聚类端点;再根据"坐标系-权重准则"确定各组聚类端点的融合顺序;最终在保证笔画平行关系的前提下,对各聚类端点按照其相应的权重顺序进行融合处理.通过自主开发的FSR_EF原型系统对文中方法予以验证并与现有方法进行比较,结果证明,该方法可以有效地解决现有端点融合方法存在的问题,也达到保留用户最初输入意图的目的,同时为进一步实现3D物体投影图的重构工作奠定了基础.

Endpoint fusing is highly important in the process of regularizing the sketch. We propose a new method based on angular histogram for endpoint fusing. Firstly, parallel processing is used to treat gestures that are the result of recognizing and fitting the strokes; Then judging and determining the cluster endpoints by using adaptive tolerance circles. After that, the order of endpoints fusing is settled according to the regulation of ‘coordinate system-weight’. Finally, endpoints fusing process is carried out under the premise of keeping parallel before.This paper develops a human-computer interface prototype system FSR_EF using the proposed algorithm above. Experimental results on various freehand projection sketches in FSR_EF show that the proposed approach provides a good solution to these limitations embedded with most existing sketching systems which only simply conduct pinching without considering context of the sketch. In addition, the test results largely reserve the user’s initial intentions and show that the method achieves an acceptable fruit.