alignMajor.py 文件源码

def get_major_minor_axis(img):
    """
    Finds the major and minor axis as 3d vectors of the passed in image
    :param img: CZYX numpy array
    :return: tuple containing two numpy arrays representing the major and minor axis as 3d vectors
    """
    # do a mean projection if more than 3 axes
    if img.ndim > 3:
        z, y, x = np.nonzero(np.mean(img, axis=tuple(range(img.ndim - 3))))
    else:
        z, y, x = np.nonzero(img)
    coords = np.stack([x - np.mean(x), y - np.mean(y), z - np.mean(z)])
    # eigenvectors and values of the covariance matrix
    evals, evecs = np.linalg.eig(np.cov(coords))
    # return largest and smallest eigenvectors (major and minor axis)
    order = np.argsort(evals)
    return (evecs[:, order[-1]], evecs[:, order[0]])