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手绘 CAD 图形输入的识别
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作者 周辉 欧宗瑛 王金鹤 《机械科学与技术》 EI CSCD 北大核心 1998年第2期332-333,336,共3页
讨论了手绘CAD图形输入的识别问题,提出了手绘图形识别方法,对曲线进行线性逼近以抑制噪声并减少识别数据量,提取几何与非几何特征进行粗分段,在此基础上利用基于BP算法的神经网络分类器进行直线和圆弧的分离和识别,以正确实... 讨论了手绘CAD图形输入的识别问题,提出了手绘图形识别方法,对曲线进行线性逼近以抑制噪声并减少识别数据量,提取几何与非几何特征进行粗分段,在此基础上利用基于BP算法的神经网络分类器进行直线和圆弧的分离和识别,以正确实现分段识别并重构图形。 展开更多
关键词 手绘图 CAD 曲线线性逼近 人工神经网络
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一种新颖的图像抗渐晕技术 被引量:5
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作者 冯强 霍俊彦 杨海涛 《电子科技》 2007年第10期67-70,共4页
渐晕效果(Vignetting)是指在光学系统输出端的信号产生与位置有关的亮度衰减,使得图像的外围出现阴影的现象。文中在分析现有算法的基础上提出了一种线性逼近的算法。该方法能够有效地去除渐晕效果,并具有内存占用小,运算复杂度低等优点。
关键词 VIGNETTING LUT 线性逼近曲线
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Optimal approximate merging of a pair of Bézier curves with G^2-continuity 被引量:3
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作者 Ping ZHU Guo-zhao WANG 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2009年第4期554-561,共8页
We present a novel approach for dealing with optimal approximate merging of two adjacent Bezier eurves with G^2-continuity. Instead of moving the control points, we minimize the distance between the original curves an... We present a novel approach for dealing with optimal approximate merging of two adjacent Bezier eurves with G^2-continuity. Instead of moving the control points, we minimize the distance between the original curves and the merged curve by taking advantage of matrix representation of Bezier curve's discrete structure, where the approximation error is measured by L2-norm. We use geometric information about the curves to generate the merged curve, and the approximation error is smaller. We can obtain control points of the merged curve regardless of the degrees of the two original curves. We also discuss the merged curve with point constraints. Numerical examples are provided to demonstrate the effectiveness of our algorithms. 展开更多
关键词 Approximate merging Gl-continuity G^2-continuity Discrete subdivision Point constraints
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