detect.py 文件源码

def CEM(M, t):
    """
    Performs the constrained energy minimization 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:
        Qian Du, Hsuan Ren, and Chein-I Cheng. A Comparative Study of
        Orthogonal Subspace Projection and Constrained Energy Minimization.
        IEEE TGRS. Volume 41. Number 6. June 2003.
    """
    def corr(M):
        p, N = M.shape
        return np.dot(M, M.T) / N

    N, p = M.shape
    R_hat = corr(M.T)
    Rinv = lin.inv(R_hat)
    denom = np.dot(t.T, np.dot(Rinv, t))
    t_Rinv = np.dot(t.T, Rinv)
    return np.dot(t_Rinv , M[0:,:].T) / denom