detect.py 文件源码

def GLRT(M, t):
    """
    Performs the generalized likelihood test ratio algorithm for target
    detection.

    Parameters:
        M: `numpy array`
            2d matrix of HSI data (N x p).

        t: `numpy array`
            A target endmember (p).

    Returns: `numpy array`
        Vector of detector output (N).

    References:
        T F AyouB, "Modified GLRT Signal Detection Algorithm," IEEE
        Transactions on Aerospace and Electronic Systems, Vol 36, No 3, July
        2000.
    """
    N, p = M.shape

    # Remove mean from data
    u = M.mean(axis=0)
    M = M - np.kron(np.ones((N, 1)), u)
    t = t - u;

    R = lin.inv(np.cov(M.T))
    results = np.zeros(N, dtype=np.float)

    t_R_t_dot = np.dot(t, np.dot(R, t.T))
    for k in range(N):
        x = M[k]
        R_x_dot = np.dot(R, x)
        num = np.dot(t, R_x_dot)**2
        denom = t_R_t_dot * (1 + np.dot(x.T, R_x_dot))
        results[k] = num / denom
    return results