Connect ROS Camera Simulation to Opencv

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connectcam.py

#! /usr/bin/env python 
import sys
sys.path.remove('/opt/ros/kinetic/lib/python2.7/dist-packages')
import cv2
sys.path.append('/opt/ros/kinetic/lib/python2.7/dist-packages')
from cv_bridge import CvBridge, CvBridgeError
import roslib
#roslib.load_manifest('camera_test')
import rospy 
from sensor_msgs.msg import Image,CompressedImage
import numpy as np


class image_converter:
	def __init__(self):
		self.bridge = CvBridge()
		self.image_sub = rospy.Subscriber('/arm_sensor/camera/image_raw/compressed',CompressedImage,self.callback,queue_size=1)
	def callback(self,data):
		try:
			np_arr = np.fromstring(data.data,np.uint8)
			cv_image = cv2.imdecode(np_arr,cv2.IMREAD_COLOR)
		except CvBridgeError as e:
			print(e)
		rows,cols,channels = cv_image.shape
		cv2.imshow('Image window',cv_image)
		cv2.waitKey(2)


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)
    

connectcam.launch

<launch>
	<node pkg="camera_test" type="connectcam.py" name="image_converter" output="screen">
	</node>
</launch>
    

References

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1. Python CompressedImage Subscriber Publisher
2. Converting between ROS images and OpenCV images (Python)
3. import cv2 error caused by ROS!