util.py 文件源码

def match_color_histogram(x, y):
    z = np.zeros_like(x)
    shape = x[0].shape
    for i in six.moves.range(len(x)):
        a = x[i].reshape((3, -1))
        a_mean = np.mean(a, axis=1, keepdims=True)
        a_var = np.cov(a)
        d, v = np.linalg.eig(a_var)
        d += 1e-6
        a_sigma_inv = v.dot(np.diag(d ** (-0.5))).dot(v.T)

        b = y[i].reshape((3, -1))
        b_mean = np.mean(b, axis=1, keepdims=True)
        b_var = np.cov(b)
        d, v = np.linalg.eig(b_var)
        b_sigma = v.dot(np.diag(d ** 0.5)).dot(v.T)

        transform = b_sigma.dot(a_sigma_inv)
        z[i,:] = (transform.dot(a - a_mean) + b_mean).reshape(shape)
    return z