I have solved this issue and I was thinking that sharing the real solution is a good idea with others:
import rospy
import math
from sensor_msgs.msg import LaserScan
from math import *
import numpy as np
import copy
ranges_filter = []
intensities_filter = []
#copy the range and intensities of "/scan" topic to "ranges_filter" and "intensities_filter"
#you need to convert them to "list" as "data.ranges" and "data.intensities" are "tuple"
def callback_scan(data):
global ranges_filter, intensities_filter
len(data.ranges) #360
len(data.intensities) #360
ranges_filter = copy.copy(data.ranges)
intensities_filter = copy.copy(data.intensities)
#convert them to list
ranges_filter = list(ranges_filter)
intensities_filter = list(intensities_filter)
#filtering those angles that I do not want them (based on the question)
for x in range(45, 135):
ranges_filter[x] = 0
intensities_filter[x] = 0
for y in range(225, 315):
ranges_filter[y] = 0
intensities_filter[y] = 0
#define a new topic called "filterScan" to store all laser scanner data
rospy.init_node('laser_scan_filter')
scan_pub = rospy.Publisher('filterScan', LaserScan, queue_size=50)
rospy.Subscriber("/scan", LaserScan, callback_scan)
#it is based on the type of laser scanner (length of data.ranges)
num_readings = 360
laser_frequency = 60
count = 0
r = rospy.Rate(1.0)
while not rospy.is_shutdown():
current_time = rospy.Time.now()
filterScan = LaserScan()
filterScan.header.stamp = current_time
filterScan.header.frame_id = 'base_scan'
filterScan.angle_min = 0 # start angle of the scan [rad]
filterScan.angle_max = math.pi * 2 # end angle of the scan [rad]
filterScan.angle_increment = 0.0174532923847 # angular distance between measurements [rad]
filterScan.time_increment = 2.98699997074e-05 # time between measurements [seconds]
filterScan.range_min = 0.0 # minimum range value [m]
filterScan.range_max = 3.5 # maximum range value [m]
filterScan.ranges = []
filterScan.intensities = []
for i in range(0, num_readings-1):
filterScan.ranges = copy.copy(ranges_filter)
filterScan.intensities = copy.copy(intensities_filter)
scan_pub.publish(filterScan)
r.sleep()
I have done it in Python and the code is working perfectly fine for Turtlebot3-Burger.
Originally posted by maziarser with karma: 68 on 2018-01-05
This answer was ACCEPTED on the original site
Post score: 3
Original comments
Comment by gvdhoorn on 2018-01-05:
+1 for posting your solution, that is always appreciated.
Was there any specific reason you could not use one of the filters from the laser_filters package?
Comment by maziarser on 2018-01-05:
@gvdhoom, thanks for your comment. No, that would be another solution. I think, the posted answer can help those people who are making apps for end users to work with robots.
Comment by sujeet on 2018-07-29:
Hello, I edited the turtlebot3_slam.launch and put a node for laser_filters over there. Furthermore, I created another file test.yaml in the same location of the launch file and put the maximum and minimum angles. The launch file ran without error but there was no change according to the filter.