diff --git a/camera_info_manager_py/camera_info_manager/camera_info_manager.py b/camera_info_manager_py/camera_info_manager/camera_info_manager.py
index 1360e289..f4080373 100644
--- a/camera_info_manager_py/camera_info_manager/camera_info_manager.py
+++ b/camera_info_manager_py/camera_info_manager/camera_info_manager.py
@@ -41,6 +41,7 @@
 
 """
 
+import array
 import errno
 import locale
 import os
@@ -48,12 +49,22 @@
 
 from ament_index_python import get_package_share_directory
 from ament_index_python import PackageNotFoundError
+import numpy as np
 import rclpy
 from rclpy.node import Node
 from sensor_msgs.msg import CameraInfo
 from sensor_msgs.srv import SetCameraInfo
 import yaml
 
+
+def _ndarray_representer(dumper: yaml.Dumper, array: np.ndarray) -> yaml.Node:
+    """Make yaml output a numpy array as though it were a simple list."""
+    return dumper.represent_list(array.tolist())
+
+
+yaml.SafeDumper.add_representer(np.ndarray, _ndarray_representer)
+yaml.SafeDumper.add_representer(array.array, yaml.representer.Representer.represent_list)
+
 default_camera_info_url = 'file://${ROS_HOME}/camera_info/${NAME}.yaml'
 # parseURL() type codes:
 URL_empty = 0  # empty string
@@ -326,7 +337,7 @@ def loadCameraInfo(self):
         """
         self._loadCalibration(self.url, self.cname)
 
-    def setCameraInfo(self, req):
+    def setCameraInfo(self, req, rsp):
         """
         Set camera info request callback.
 
@@ -339,7 +350,6 @@ def setCameraInfo(self, req):
         """
         self.node.get_logger().debug('SetCameraInfo received for ' + self.cname)
         self.camera_info = req.camera_info
-        rsp = SetCameraInfo.Response()
         rsp.success = saveCalibration(req.camera_info, self.url, self.cname)
         if not rsp.success:
             rsp.status_message = 'Error storing camera calibration.'