利用最小二乘法进行拟合多元非线性方程，结合PCA的尺度不变特征变换(SIFT)算法，最大似然（ML）准则和最大后验概率（MAP）准则。- Multivariate least squares fitting method of nonlinear equations, Combined with PCA scale invariant feature transform (SIFT) algorithm, Maximum Likelihood (ML) criteria and maximum a posteriori (MAP) criterion.