ellipse.py 文件源码

def fit_ellipse(x,y):
    x = x[:,NP.newaxis]
    y = y[:,NP.newaxis]
    D =  NP.hstack((x*x, x*y, y*y, x, y, NP.ones_like(x)))
    S = NP.dot(D.T,D)
    C = NP.zeros([6,6])
    C[0,2] = C[2,0] = 2; C[1,1] = -1
    E, V =  eig(NP.dot(inv(S), C))
    n = NP.argmax(NP.abs(E))
    a = V[:,n]
    return a