dist.py 文件源码

def SID(s1, s2):
    """
    Computes the spectral information divergence between two vectors.

    Parameters:
        s1: `numpy array`
            The first vector.

        s2: `numpy array`
            The second vector.

    Returns: `float`
            Spectral information divergence between s1 and s2.

    Reference
        C.-I. Chang, "An Information-Theoretic Approach to SpectralVariability,
        Similarity, and Discrimination for Hyperspectral Image"
        IEEE TRANSACTIONS ON INFORMATION THEORY, VOL. 46, NO. 5, AUGUST 2000.

    """
    p = (s1 / np.sum(s1)) + np.spacing(1)
    q = (s2 / np.sum(s2)) + np.spacing(1)
    return np.sum(p * np.log(p / q) + q * np.log(q / p))