The launch file must ideally run the simulator alongwith the required nodes in the whycon package to detect markers in the image published by the overhead camera in Gazebo and should output a window of detected WhyCon markers

#!/usr/bin/env python

import rospy
import roslib
import tf

from geometry_msgs.msg import PoseArray

#Defining a class
class Marker_detect():

    def __init__(self):
        rospy.init_node('marker_detection',anonymous=False) # initializing a ros node with name marker_detection

        self.whycon_marker = {} # Declaring dictionaries

        rospy.Subscriber('/whycon/poses',PoseArray,self.whycon_data)    # Subscribing to topic

    # Callback for /whycon/poses
    # Please fill in the function
    def whycon_data(self,msg):


        # Printing the detected markers on terminal
        print(self.whycon_marker)


if __name__=="__main__":
    marker = Marker_detect()
    while not rospy.is_shutdown():
        rospy.spin()