diff --git a/camera_calibration/src/camera_calibration/calibrator.py b/camera_calibration/src/camera_calibration/calibrator.py
index cca9a0d75..9d5b3a31d 100644
--- a/camera_calibration/src/camera_calibration/calibrator.py
+++ b/camera_calibration/src/camera_calibration/calibrator.py
@@ -482,6 +482,7 @@ def mk_object_points(self, boards, use_board_size = False):
         if self.pattern == Patterns.ChArUco:
             opts = [board.charuco_board.chessboardCorners for board in boards]
             return opts
+        opts = []
         for b in boards:
             num_pts = b.n_cols * b.n_rows
             opts_loc = numpy.zeros((num_pts, 1, 3), numpy.float32)