def _mask_border_keypoints(image_shape, keypoints, distance):
    """Mask coordinates that are within certain distance from the image border.

    Parameters
    ----------
    image_shape : (2, ) array_like
        Shape of the image as ``(rows, cols)``.
    keypoints : (N, 2) array
        Keypoint coordinates as ``(rows, cols)``.
    distance : int
        Image border distance.

    Returns
    -------
    mask : (N, ) bool array
        Mask indicating if pixels are within the image (``True``) or in the
        border region of the image (``False``).

    """
    rows = image_shape[0]
    cols = image_shape[1]
    mask = (distance - 1 < keypoints[:, (0)]) & (keypoints[:, (0)] < rows -
        distance + 1) & (distance - 1 < keypoints[:, (1)]) & (keypoints[:,
        (1)] < cols - distance + 1)
    return mask
