基于特定椭圆拟合的符号化目标轮廓跟踪方法 基于稳健估计的直接最小二乘椭圆拟合 椭圆拟合方法的比较研究-Ellipse fitting symbol based on the specific goal of contour tracking method is based on robust estimation of the direct least squares ellipse fitting ellipse fitting method comparison studies