从所给图形中分别抓取12个点，然后弦长参数化并利用控制顶点与型值点间的关系计算出迭代矩阵，以抓取到的点作为型值点分别用jaccobi和Gauss-seidel迭代法进行迭代，得到控制顶点。然后将给出的控制顶点与算出的控制顶点分别代入中得到P(t)和Q（t）,再采用二范数估计误差(According to the graphics respectively to grab 12 points, then the chord length parameterization and the control points and the value relations between points calculated by iterative matrix, to capture the point as the data points are iteratively using Jaccobi and Gauss-seidel iterative method, get the control points. Then, the control points and the calculated control points are substituted into P (T) and Q (T) respectively, and then the two norm estimation error is adopted)