inverse_depth.py 文件源码

def linearity_index_inverse_depth():
    """Linearity index of Inverse Depth Parameterization"""
    D, rho, rho_0, d_1, sigma_rho = sympy.symbols("D,rho,rho_0,d_1,sigma_rho")
    alpha = sympy.symbols("alpha")
    u = (rho * sympy.sin(alpha)) / (rho_0 * d_1 * (rho_0 - rho) + rho * sympy.cos(alpha))  # NOQA

    # first order derivative of u
    u_p = sympy.diff(u, rho)
    u_p = sympy.simplify(u_p)

    # second order derivative of u
    u_pp = sympy.diff(u_p, rho)
    u_pp = sympy.simplify(u_pp)

    # Linearity index
    L = (u_pp * 2 * sigma_rho) / (u_p)
    L = sympy.simplify(L)

    print()
    print("u: ", u)
    print("u': ", u_p)
    print("u'': ", u_pp)
    # print("L = ", L)
    print("L = ", L.subs(rho, 0))
    print()