def depthClasses(depth_img, min_depth=500):
    """ Identify pixels in a depth image that are probably hands or arms.

    Parameters
    ----------
    depth_img : numpy array of float, shape (img_height, img_width)
    min_depth : float, optional

    Returns
    -------
    is_near_table : numpy array of bool, shape (img_height, img_width)
    """

    is_near_camera = depth_img < min_depth

    return is_near_camera