Multiple image subscriber failure.

edit

I made 2 nodes, publishing my web camera and external camera images.and I want to show both camera images with a single subscriber node. but when i run my subscriber node, it publishes camera 1 and 2 images alternatively.( if i run subscriber code for the first time it publishes camera 1 image and next time i run it publishes camera 2 images. not publishing at the same time) .can anyone please tell me what changes i have to make in my code.

camera1.py

#!/usr/bin/env python

import rospy
from sensor_msgs.msg import Image
import cv2
import numpy as np
from cv_bridge import CvBridge, CvBridgeError

def webcam_pub():
    pub = rospy.Publisher('camera1', Image, queue_size=1)
    rospy.init_node('webcam_pub', anonymous=True)
    rate = rospy.Rate(60) # 60hz

    cam = cv2.VideoCapture(1)
    bridge = CvBridge()

    if not cam.isOpened():
         sys.stdout.write("Webcam is not available")
         return -1

    while not rospy.is_shutdown():
        ret, frame = cam.read()


    msg = bridge.cv2_to_imgmsg(frame, encoding="bgr8")

        if ret:
            rospy.loginfo("Capturing image failed.")

        pub.publish(msg)
        rate.sleep()


if __name__ == '__main__':
    try:
        webcam_pub()
    except rospy.ROSInterruptException:
      pass

camera2.py

#!/usr/bin/env python

import rospy
from sensor_msgs.msg import Image
import cv2
import numpy as np
from cv_bridge import CvBridge, CvBridgeError

def webcam_pub():
    pub = rospy.Publisher('camera2', Image, queue_size=1)
    rospy.init_node('webcam_pub', anonymous=True)
    rate = rospy.Rate(60) # 60hz

    cam = cv2.VideoCapture(0)
    bridge = CvBridge()

    if not cam.isOpened():
         sys.stdout.write("Webcam is not available")
         return -1

    while not rospy.is_shutdown():
        ret, frame = cam.read()


    msg = bridge.cv2_to_imgmsg(frame, encoding="bgr8")

        if ret:
            rospy.loginfo("Capturing image failed.")

        pub.publish(msg)
        rate.sleep()


if __name__ == '__main__':
    try:
        webcam_pub()
    except rospy.ROSInterruptException:
      pass

Listener.py

#!/usr/bin/env python
from __future__ import print_function

#import roslib
#roslib.load_manifest('my_package')
import sys
import rospy
import cv2
from std_msgs.msg import String
from sensor_msgs.msg import Image
from cv_bridge import CvBridge, CvBridgeError

class image_converter:

  def __init__(self):
     self.image_pub = rospy.Publisher("image",Image,  queue_size=1)

     self.bridge = CvBridge()
     self.image_sub = rospy.Subscriber("camera2",Image,self.callback)
     self.image_sub1 = rospy.Subscriber("camera1",Image,self.callback1)

  def callback(self,data):
     try:
       cv_image = self.bridge.imgmsg_to_cv2(data, "bgr8")
     except CvBridgeError as e:
       print(e)


     cv2.imshow("Camera 2", cv_image)
     cv2.waitKey(3)

     try:
       self.image_pub.publish(self.bridge.cv2_to_imgmsg(cv_image, "bgr8"))
     except CvBridgeError as e:
       print(e)
  def callback1(self,data):
     try:
       cv_image1 = self.bridge.imgmsg_to_cv2(data, "bgr8")
     except CvBridgeError as e:
       print(e)


     cv2.imshow("Camera 1", cv_image1)
     cv2.waitKey(3)

     try:
       self.image_pub.publish(self.bridge.cv2_to_imgmsg(cv_image1, "bgr8"))
     except CvBridgeError as e:
       print(e)

def main(args):
   ic = image_converter()
   rospy.init_node('image_converter', anonymous=True)
   try:
     rospy.spin()
   except KeyboardInterrupt:
     print("Shutting down")
   cv2.destroyAllWindows()

if __name__ == '__main__':
     main(sys.argv)