uav_camera_to_crutch_proxy.py

 
# Import the necessary libraries
import rclpy # Python library for ROS 2
from rclpy.node import Node # Handles the creation of nodes
from sensor_msgs.msg import Image #import Image # Image is the message type
from cv_bridge import CvBridge # Package to convert between ROS and OpenCV Images
import cv2 # OpenCV library

#=======================
import base64
import zmq

context = zmq.Context()
footage_socket = context.socket(zmq.PUB)
footage_socket.connect('tcp://localhost:5555')
#=======================

import threading


#======================================================================================
#ROS2 to OCV image
class ImageSubscriber(rclpy.node.Node):
  """
  Create an ImageSubscriber class, which is a subclass of the Node class.
  """
  def __init__(self):
    """
    Class constructor to set up the node
    """
    print(11)
    # Initiate the Node class's constructor and give it a name
    super().__init__('image_subscriber')
    print(22)
    # Create the subscriber. This subscriber will receive an Image
    # from the video_frames topic. The queue size is 10 messages.
    self.subscription = self.create_subscription(
      Image, 
      'camera', 
      self.listener_callback, 
      10)
    self.subscription # prevent unused variable warning
      
    # Used to convert between ROS and OpenCV images
    self.br = CvBridge()
   
  def listener_callback(self, data):
    """
    Callback function.
    """
    # Display the message on the console
    self.get_logger().info('Receiving video frame')
 
    # Convert ROS Image message to OpenCV image
    current_frame = self.br.imgmsg_to_cv2(data, desired_encoding="bgr8")
    image = current_frame
    #===========================================
    frame2 = cv2.resize(image, (640, 480))  # resize the frame
    encoded, buffer = cv2.imencode('.jpg', frame2)
    jpg_as_text = base64.b64encode(buffer)
    footage_socket.send(jpg_as_text)

    #===========================================
    #image_frame = iamge
    #gorFrame = True 
    print(77777)
    # Show Results
    cv2.imshow('Detected Frame', image)    
    cv2.waitKey(1)
    

    
    
def main(args=None):
  
  # Initialize the rclpy library
  rclpy.init(args=args)
  
  # Create the node
  image_subscriber = ImageSubscriber()
  
  # Spin the node so the callback function is called.
  rclpy.spin(image_subscriber)
  
  # Destroy the node explicitly
  # (optional - otherwise it will be done automatically
  # when the garbage collector destroys the node object)
  image_subscriber.destroy_node()
  
  # Shutdown the ROS client library for Python
  rclpy.shutdown()
  
#=================================================================================================================================== 
main()