一种基于曲线拟合提取干涉条纹中心点的新方法

介绍一种提取干涉条纹中心点的边界法向曲线拟合法。根据干涉条纹灰度分布规律，首先对干涉图像依次进行二值化处理和边缘提取，对所得到的条纹边缘进行曲线拟合，计算边缘上各点法线方向；再根据条纹灰度余弦分布特点，对法线方向上的条纹灰度数据进行最小二乘法拟合，求出极值点位置；进而获得条纹中心点坐标。该方法具有精度高、抗干扰的特点，不仅适用于平行直线型条纹图像，而且对含闭合条纹的复杂干涉图像同样适用。

A New Method of Extracting the Center Inerference Fringes Based on Polynomial Fitting

A new method of extracting the center of interference fringes is proposed based on polynomial fitting,which is named as the polynomial fitting method along the normal direction of fringe edges. According to fringe gray distribution,firstly the interferograms are compressed to 2 gray-level images,and the fringe edges are extracted. Secondly, by fitting the data of fringe edges with polynomials, the normal direction of the edges is defined. Then based on the characteristics of fringe gray cosine distribution, the extremum is obtained by using least square method to fit the gray data of fringes along the normal direction ,and the coordinate of the center is obtained. This method is good at measurement precision and has anti-jamming power. It has been proved that this method is fit for the parallel linable fringes and the interferograms with the arbitrary closed loop fringe pattern.