Fairness Factor Method for Quantitative Analysis of Curve Fairness
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摘要: 目前产品的光顺效果评定大都基于定性分析。针对现有评定方法主观性强，计算效率低下等缺陷，提出一种定量评定光顺效果的方法。该方法先将曲线平移变换以消除坐标的影响，然后进行小波光顺，基于小波光顺前后曲线的尺度，定义修正系数α，修正小波光顺后的细节部分，由修正后的细节部分和尺度部分构建光顺性定量指标光顺因子λ，通过计算光顺因子λ实现定量评定光顺效果。工程实例表明，提出的定量分析方法可作为光顺效果评定的可靠工具。Abstract: The current evaluation of the fairing effect of a product is mainly based on qualitative analysis. To overcome the defects of the existing evaluation methods, such as subjectivity and low computation efficiency, a quantitative method is proposed. Firstly, the curve is translated to eliminate the influence of the coordinates. Secondly, the curve is faired by wavelet decomposition. Then the detail part is corrected by the correction coefficient α defined by the wavelets fairing scales. Finally, the corrected detail part and the scale part are used to construct the fairness quantity index λ, which is also called fairness factor. The fairing effect can be evaluated quantitatively by calculating the fairness factor λ. An engineering example is given to demonstrate that the method can be used as a reliable tool for evaluating the fairing effect of the product.
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Key words:
- fairness /
- wavelets fairing /
- correction coefficient /
- fairness factor /
- quantitative analysis
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表 1 曲线1光顺6次的修正系数和光顺因子
光顺次数 控制点数 修正系数α 光顺因子λ 1 85 0.286 46 0.052 83 2 67 0.142 86 0.036 51 3 51 0.063 70 0.021 92 4 35 0.020 41 0.011 90 5 19 0.002 92 0.008 09 6 10 0.000 29 0.004 81 
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表 2 曲线2光顺4次的修正系数和光顺因子
光顺次数 控制点数 修正系数α 光顺因子λ αλ 1 67 0.142 86 0.000 26 2 51 0.063 70 0.000 22 3 35 0.020 41 0.000 20 4 19 0.002 92 0.000 12
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表 3 旗鱼曲线光顺的修正系数及光顺因子
光顺次数 控制点数 修正系数α 光顺因子λ 1 45 0.584 91 0.004 81 2 35 0.295 48 0.003 43 3 25 0.115 23 0.002 12 4 15 0.025 17 0.001 82 5 9 0.004 42 0.001 68
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