ROS2: bridge.cv2_to_imgmsg is very slow

edit

Hello,

I wrote a simple image publisher. It loads rgb data from Realsense depth camera, converts them to sensor_msgs/msg/Image via cv_bridge and publishes them. Problem is that command

msg = bridge.cv2_to_imgmsg(color_image, encoding="passthrough")

takes about one second, resulting to ~1fps publish rate. Lowering image resolution will help, but to have somewhat decent fps, resolution has to be as low as 320x240.

I dont have much expirience using ROS, please comment if additional information would help to decide what is wrong. Thanks for any help!

code from main:

rclpy.init(args=args)
bridge = CvBridge()
node = rclpy.create_node('image_publisher')
publisher = node.create_publisher(Image, 'image')
pipeline.start(config)
msg = Image()

def timer_callback():
    # Convert images to numpy arrays
    frames = pipeline.wait_for_frames()
    color_frame = frames.get_color_frame()
    color_image = np.asanyarray(color_frame.get_data())

    # when commented out, publish rate is extremely high:
    msg = bridge.cv2_to_imgmsg(color_image, encoding="passthrough")


    print("Message published")
    publisher.publish(msg)

timer_period = 0
timer = node.create_timer(timer_period, timer_callback)

rclpy.spin(node)
node.destroy_timer(timer)
node.destroy_node()
rclpy.shutdown()