csr.py 文件源码

def compute_centroids(image):
    """Find the centroids of all nonzero connected blobs in `image`.

    Parameters
    ----------
    image : ndarray
        The input image.

    Returns
    -------
    label_image : ndarray of int
        The input image, with each connected region containing a different
        integer label.

    Examples
    --------
    >>> image = np.array([[1, 0, 1, 0, 0, 1, 1],
    ...                   [1, 0, 0, 1, 0, 0, 0]])
    >>> labels, centroids = compute_centroids(image)
    >>> print(labels)
    [[1 0 2 0 0 3 3]
     [1 0 0 2 0 0 0]]
    >>> centroids
    array([[ 0.5,  0. ],
           [ 0.5,  2.5],
           [ 0. ,  5.5]])
    """
    connectivity = np.ones((3,) * image.ndim)
    labeled_image = ndi.label(image, connectivity)[0]
    nz = np.nonzero(labeled_image)
    nzpix = labeled_image[nz]
    sizes = np.bincount(nzpix)
    coords = np.transpose(nz)
    grouping = np.argsort(nzpix)
    sums = np.add.reduceat(coords[grouping], np.cumsum(sizes)[:-1])
    means = sums / sizes[1:, np.newaxis]
    return labeled_image, means