sample.py

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



rospy.init_node('my_node', anonymous=True)

topicRGB = "/rgb/image_color"

topicDepth ="/depth_registered/image_raw"

rgbmsg = rospy.wait_for_message(cameraName + topicRGB, Image)
depth_registeredmsg = rospy.wait_for_message(cameraName + topicDepth, Image)

#bridge to convert ROS image into numpy array
br = CvBridge()

#converts ros img to numpy array
rgb = br.imgmsg_to_cv2(rgbros, desired_encoding="bgr8")

depth= br.imgmsg_to_cv2(depthros, desired_encoding="passthrough")

cv2.imshow('image',rgb)
cv2.waitKey(0)
cv2.destroyAllWindows()

cv2.imshow('image',depth)
cv2.waitKey(0)
cv2.destroyAllWindows()