colorrange.py

import rospy
from sensor_msgs.msg import *
from cv_bridge import CvBridge
import cv2
import numpy as np
bridge = CvBridge()
rospy.init_node("Redmasker")
image_pub = rospy.Publisher("RedMasked",Image)

def img_handler(msg):
    img = bridge.imgmsg_to_cv2(msg,"bgr8")
    dat = cv2.inRange(img, np.array([0,0,0]), np.array([100,100,255]))
    img=cv2.bitwise_and(img,img,mask=dat)
    image_pub.publish(bridge.cv2_to_imgmsg(img,"bgr8"))


sub = rospy.Subscriber("/Image_topic0",Image,img_handler)
rospy.spin()