def prune_outside_window(boxlist, window):
  """Prunes bounding boxes that fall outside a given window.

  This function prunes bounding boxes that even partially fall outside the given
  window. See also ClipToWindow which only prunes bounding boxes that fall
  completely outside the window, and clips any bounding boxes that partially
  overflow.

  Args:
    boxlist: a BoxList holding M_in boxes.
    window: a numpy array of size 4, representing [ymin, xmin, ymax, xmax]
            of the window.

  Returns:
    pruned_corners: a tensor with shape [M_out, 4] where M_out <= M_in.
    valid_indices: a tensor with shape [M_out] indexing the valid bounding boxes
     in the input tensor.
  """

  y_min, x_min, y_max, x_max = np.array_split(boxlist.get(), 4, axis=1)
  win_y_min = window[0]
  win_x_min = window[1]
  win_y_max = window[2]
  win_x_max = window[3]
  coordinate_violations = np.hstack([np.less(y_min, win_y_min),
                                     np.less(x_min, win_x_min),
                                     np.greater(y_max, win_y_max),
                                     np.greater(x_max, win_x_max)])
  valid_indices = np.reshape(
      np.where(np.logical_not(np.max(coordinate_violations, axis=1))), [-1])
  return gather(boxlist, valid_indices), valid_indices
Prunes bounding boxes that fall outside a given window.

  This function prunes bounding boxes that even partially fall outside the given
  window. See also ClipToWindow which only prunes bounding boxes that fall
  completely outside the window, and clips any bounding boxes that partially
  overflow.

  Args:
    boxlist: a BoxList holding M_in boxes.
    window: a numpy array of size 4, representing [ymin, xmin, ymax, xmax]
            of the window.

  Returns:
    pruned_corners: a tensor with shape [M_out, 4] where M_out <= M_in.
    valid_indices: a tensor with shape [M_out] indexing the valid bounding boxes
     in the input tensor.
  
inference_api/src/main/object_detection/utils/np_box_list_ops.py