box_list_ops.py 文件源码

def prune_outside_window(boxlist, window, scope=None):
  """Prunes bounding boxes that fall outside a given window.

  This function prunes bounding boxes that even partially fall outside the given
  window. See also clip_to_window 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 float tensor of shape [4] representing [ymin, xmin, ymax, xmax]
      of the window
    scope: name scope.

  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.
  """
  with tf.name_scope(scope, 'PruneOutsideWindow'):
    y_min, x_min, y_max, x_max = tf.split(
        value=boxlist.get(), num_or_size_splits=4, axis=1)
    win_y_min, win_x_min, win_y_max, win_x_max = tf.unstack(window)
    coordinate_violations = tf.concat([
        tf.less(y_min, win_y_min), tf.less(x_min, win_x_min),
        tf.greater(y_max, win_y_max), tf.greater(x_max, win_x_max)
    ], 1)
    valid_indices = tf.reshape(
        tf.where(tf.logical_not(tf.reduce_any(coordinate_violations, 1))), [-1])
    return gather(boxlist, valid_indices), valid_indices