symbol_grounding_scan_base_pose_server.py

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#!/usr/bin/env python
#################################################################
##\file
#
# \note
# Copyright (c) 2012 \n
# University of Bedfordshire \n\n
#
#################################################################
#
# \note
# Project name: care-o-bot
# \note
# ROS stack name: srs_public
# \note
# ROS package name: srs_symbolic_grounding
#
# \author
# Author: Beisheng Liu, email:beisheng.liu@beds.ac.uk
# \author
# Supervised by: Dayou Li, email:dayou.li@beds.ac.uk
#
# \date Date of creation: Mar 2012
#
# \brief
# Grounding scan object surface commands
#
#################################################################
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# - Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer. \n
# - Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution. \n
# - Neither the name of the University of Bedfordshire nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission. \n
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License LGPL as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License LGPL for more details.
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# You should have received a copy of the GNU Lesser General Public
# License LGPL along with this program.
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#################################################################

import roslib; roslib.load_manifest('srs_symbolic_grounding')
from srs_symbolic_grounding.srv import *
#from srs_symbolic_grounding.msg import *
from std_msgs.msg import *
from geometry_msgs.msg import *
from nav_msgs.msg import *
from nav_msgs.srv import *
#from srs_knowledge.msg import *
import rospy
import math
import tf
from tf.transformations import euler_from_quaternion
import csv
'''
def getWorkspaceOnMap():
        print 'test get all workspace (furnitures basically here) from map'
        try:
                requestNewTask = rospy.ServiceProxy('get_workspace_on_map', GetWorkspaceOnMap)
                res = requestNewTask('ipa-kitchen-map', True)
                return res
        except rospy.ServiceException, e:
                print "Service call failed: %s"%e
'''

def getMapClient(): #read map from navigation service

        try:
                reqMap = rospy.ServiceProxy('static_map', GetMap)       
                res = reqMap()
                return res
        except rospy.ServiceException, e:
                print "Service call failed: %s"%e



def obstacleCheck(sbpl, fgl, po_x, po_y): 
        obstacle_checked_scan_base_pose_list = list() #used to save obstacle checked poses
        wall_checked_scan_base_pose_list = list() #used to save wall checked poses
        all_checked_scan_base_pose_list = list()
        scan_base_pose_list = sbpl #read inputs
        furniture_geometry_list = fgl
        parent_obj_x = po_x
        parent_obj_y = po_y

        #obstacle check
        dist_to_obstacles = 0.5  #set the minimum distance to the household furnitures
        #rospy.loginfo(math.atan(-0.5))
        #check all of the poses from the scan pose list with all the household furnitures to find a obstacle free scan pose list. the poses will be stored in obstacle_checked_scan_base_pose_list.
        index_1 = 0
        while index_1 < len(scan_base_pose_list):
                index_2 = 0
                while index_2 < len(furniture_geometry_list):
                        th = math.atan((scan_base_pose_list[index_1].y - furniture_geometry_list[index_2].pose.y) / (scan_base_pose_list[index_1].x - furniture_geometry_list[index_2].pose.x))
                        if scan_base_pose_list[index_1].x < furniture_geometry_list[index_2].pose.x and scan_base_pose_list[index_1].y > furniture_geometry_list[index_2].pose.y:
                                th = math.pi + th
                        if scan_base_pose_list[index_1].x < furniture_geometry_list[index_2].pose.x and scan_base_pose_list[index_1].y < furniture_geometry_list[index_2].pose.y:
                                th = -math.pi + th
                        delta_x = math.sqrt((scan_base_pose_list[index_1].x - furniture_geometry_list[index_2].pose.x) ** 2 + (scan_base_pose_list[index_1].y - furniture_geometry_list[index_2].pose.y) ** 2) * math.cos(th - furniture_geometry_list[index_2].pose.theta)
                        delta_y = math.sqrt((scan_base_pose_list[index_1].x - furniture_geometry_list[index_2].pose.x) ** 2 + (scan_base_pose_list[index_1].y - furniture_geometry_list[index_2].pose.y) ** 2) * math.sin(th - furniture_geometry_list[index_2].pose.theta)
                        if (delta_x <= -(furniture_geometry_list[index_2].w / 2.0 + dist_to_obstacles) or delta_x >= (furniture_geometry_list[index_2].w / 2.0 + dist_to_obstacles)) or (delta_y <= -(furniture_geometry_list[index_2].l / 2.0 + dist_to_obstacles) or delta_y >= (furniture_geometry_list[index_2].l / 2.0 + dist_to_obstacles)):
                                index_2 += 1
                        else:
                                break
                if index_2 == len(furniture_geometry_list):
                        obstacle_checked_scan_base_pose_list.append(scan_base_pose_list[index_1])
                index_1 += 1
        #rospy.loginfo(obstacle_checked_scan_base_pose_list)

        if obstacle_checked_scan_base_pose_list: #check if there is a obstacle free pose in the list.
                        
                #wall check
                data = getMapClient() #get occupancy grid map from the navigation serves 

                
                dist_to_walls = 0.5 #set the minimum distance to the walls
                threshold = 10.0 #set the threshold to decide if a pose is occupaied. >threshold:occupied.
                step_angle = 5.0 #set the step angle for putting points around the robot for the wall check (360 / step_angle points will be used)

                #check all of the poses from the obstacle_checked_scan_base_pose_list with the occupancy map to find a wall free scan pose list
                index_3 = 0
                while index_3 < len(obstacle_checked_scan_base_pose_list):
                        map_index_list = list()
                        n = 0
                        while n < int(360.0 / step_angle):
                                wall_check_point_x = obstacle_checked_scan_base_pose_list[index_3].x + dist_to_walls * math.cos(n * step_angle / 180.0 * math.pi)
                                wall_check_point_y = obstacle_checked_scan_base_pose_list[index_3].y + dist_to_walls * math.sin(n * step_angle / 180.0 * math.pi)
                                
                                #rospy.loginfo([wall_check_point_x, wall_check_point_y])

                                map_index = int((wall_check_point_y - data.map.info.origin.position.y) / data.map.info.resolution) * data.map.info.width + int((wall_check_point_x - data.map.info.origin.position.x) / data.map.info.resolution)
                                map_index_list.append(map_index)
                                n += 1
                                
                        map_index = int((obstacle_checked_scan_base_pose_list[index_3].y - data.map.info.origin.position.y) / data.map.info.resolution) * data.map.info.width + int((obstacle_checked_scan_base_pose_list[index_3].x - data.map.info.origin.position.x) / data.map.info.resolution)
                        map_index_list.append(map_index)
                        #rospy.loginfo(map_index_list)

                        index_4 = 0
                        while index_4 < len(map_index_list):
                                #rospy.loginfo(data.map.data[map_index_list[index_4]])
                                if -1 < data.map.data[map_index_list[index_4]] < threshold:
                                        index_4 += 1
                                else:
                                        break
                        if index_4 == len(map_index_list):
                                wall_checked_scan_base_pose_list.append(obstacle_checked_scan_base_pose_list[index_3])
                        index_3 += 1
        '''
        if wall_checked_scan_base_pose_list:
                step_dist = 0.05
                map_index_list = list()
                threshold = 20
                index_5 = 0
                while index_5 < len(wall_checked_scan_base_pose_list):
                        dist = math.sqrt((parent_obj_y - wall_checked_scan_base_pose_list[index_5].y) ** 2 + (parent_obj_x - wall_checked_scan_base_pose_list[index_5].x) ** 2)
                        n = 0
                        while n < int((dist - 0.5) / step_dist):
                                wall_check_point_x = wall_checked_scan_base_pose_list[index_5].x - (0.5 + n * step_dist) * math.cos(wall_checked_scan_base_pose_list[index_5].theta)
                                wall_check_point_y = wall_checked_scan_base_pose_list[index_5].y - (0.5 + n * step_dist) * math.sin(wall_checked_scan_base_pose_list[index_5].theta)
                                print([wall_check_point_x, wall_check_point_y, wall_checked_scan_base_pose_list[index_5].theta])
                                map_index = int((wall_check_point_y - data.map.info.origin.position.y) / data.map.info.resolution) * data.map.info.width + int((wall_check_point_x - data.map.info.origin.position.x) / data.map.info.resolution)
                                map_index_list.append(map_index)
                                n += 1
                        
                        index_6 = 0
                        while index_6 < len(map_index_list):
                                if -1 < data.map.data[map_index_list[index_6]] < threshold:
                                        index_6 += 1
                                else:
                                        break
                        if index_6 == len(map_index_list):
                                all_checked_scan_base_pose_list.append(wall_checked_scan_base_pose_list[index_5])
                        index_5 += 1
        '''
        return  wall_checked_scan_base_pose_list                        
        #rospy.loginfo(wall_checked_scan_base_pose_list)



#calculate scan base poses
def handle_symbol_grounding_scan_base_pose(req):

        '''
        #record the map for checking
        data = getMapClient()
        spamWriter = csv.writer(open('map_data.csv', 'wb'), delimiter=' ', quotechar='|', quoting=csv.QUOTE_MINIMAL)
        for n in range(80, 250):
                spamWriter.writerow(data.map.data[130 + 320 * n : 200 + 320 * n])
                n += 1
        '''

        '''
        #test the map
        data = getMapClient()
        #test points
        x = -3.2
        y = -0.58  
        map_index = int((y - data.map.info.origin.position.y) / data.map.info.resolution * data.map.info.width + (x - data.map.info.origin.position.x - 6.0) / data.map.info.resolution - 1)
        for n in range(-20, 100):       
                map_line = list()
                for m in range (-9, 9):
                        map_line.append(data.map.data[map_index + n * int(data.map.info.width) + m])
                        m += 1
                print map_line
                n += 1
        rospy.loginfo([data.map.info.origin.position.x, data.map.info.origin.position.y])
        rospy.loginfo([data.map.info.width, data.map.info.height])
        '''

        

        '''     
        #get furniture information from knowledge base
        workspace_info = getWorkspaceOnMap()    
        furniture_geometry_list = list()
        furniture_geometry_list = workspace_info.objectsInfo
        
        
        #transfrom list
        index = 0
        furniture_geometry_list = list()
        while index < len(furniture_geometry_list):
                furniture_geometry = FurnitureGeometry()
                furniture_geometry.pose.x = furniture_geometry_list[index].pose.position.x
                furniture_geometry.pose.y = furniture_geometry_list[index].pose.position.y
                furniture_pose_rpy = tf.transformations.euler_from_quaternion([furniture_geometry_list[index].pose.orientation.x, furniture_geometry_list[index].pose.orientation.y, furniture_geometry_list[index].pose.orientation.z, furniture_geometry_list[index].pose.orientation.w])             
                furniture_geometry.pose.theta = furniture_pose_rpy[2]
                furniture_geometry.l = furniture_geometry_list[index].l
                furniture_geometry.w = furniture_geometry_list[index].w
                furniture_geometry.h = furniture_geometry_list[index].h
                furniture_geometry_list.append(furniture_geometry)
                index += 1


        
        '''

        #transform from knowledge base data to function useable data    
        parent_obj_x = req.parent_obj_geometry.pose.position.x
        parent_obj_y = req.parent_obj_geometry.pose.position.y
        parent_obj_rpy = tf.transformations.euler_from_quaternion([req.parent_obj_geometry.pose.orientation.x, req.parent_obj_geometry.pose.orientation.y, req.parent_obj_geometry.pose.orientation.z, req.parent_obj_geometry.pose.orientation.w])
        parent_obj_th = parent_obj_rpy[2]
        parent_obj_l = req.parent_obj_geometry.l
        parent_obj_w = req.parent_obj_geometry.w
        parent_obj_h = req.parent_obj_geometry.h

        #rpy = tf.transformations.euler_from_quaternion([0, 0, -0.68, 0.73])
        #rospy.loginfo(rpy[2])

        #rospy.loginfo(req.parent_obj_geometry)

        
        #transfrom furniture geometry list
        index = 0
        furniture_geometry_list = list()
        while index < len(req.furniture_geometry_list):
                furniture_geometry = FurnitureGeometry()
                furniture_geometry.pose.x = req.furniture_geometry_list[index].pose.position.x
                furniture_geometry.pose.y = req.furniture_geometry_list[index].pose.position.y
                furniture_pose_rpy = tf.transformations.euler_from_quaternion([req.furniture_geometry_list[index].pose.orientation.x, req.furniture_geometry_list[index].pose.orientation.y, req.furniture_geometry_list[index].pose.orientation.z, req.furniture_geometry_list[index].pose.orientation.w])             
                furniture_geometry.pose.theta = furniture_pose_rpy[2]
                furniture_geometry.l = req.furniture_geometry_list[index].l
                furniture_geometry.w = req.furniture_geometry_list[index].w
                furniture_geometry.h = req.furniture_geometry_list[index].h
                furniture_geometry_list.append(furniture_geometry)
                index += 1
        
        

        #calculate the detection width
        rb_distance = 1.0#0.7 #distance between the robot base and the edge of the parent obj
        robot_h = 1.4 #set the height of the detector
        detection_angle = (30.0 / 180.0) * math.pi #set the detection angle (wide) of the detector 
        camera_distance = math.sqrt((robot_h - parent_obj_h) ** 2 + (rb_distance - 0.2) ** 2) #distance between the detector and the surface of the parent obj
        detection_w = 2 * (camera_distance * math.tan(0.5 * detection_angle)) #detection wide
        #rospy.loginfo(detection_w)






        
        #variable structure define
        scan_base_pose_1 = Pose2D()
        scan_base_pose_2 = Pose2D()
        scan_base_pose_3 = Pose2D()
        scan_base_pose_4 = Pose2D()
        
        #create lists to store scan base poses
        scan_base_pose_list_1 = list()
        scan_base_pose_list_2 = list()
        scan_base_pose_list_3 = list()
        scan_base_pose_list_4 = list()

        #fix angle problem
        if parent_obj_th < 0:
                parent_obj_th += 2.0 * math.pi

        elif parent_obj_th > 2.0 * math.pi:
                parent_obj_th -= 2.0 * math.pi
        #rospy.loginfo(parent_obj_th)


        #to decide which side of the table is facing the robot 
        if ((parent_obj_th >= 0) & (parent_obj_th <= (45.0 / 180.0 * math.pi))) | ((parent_obj_th >= (135.0 / 180.0 * math.pi)) & (parent_obj_th <= (225.0 / 180.0 * math.pi))) | ((parent_obj_th >= (315.0 / 180.0 * math.pi)) & (parent_obj_th < 360)):
                
                #calculate 4 lists of scan poses, each list is for scanning from one side of the table.
                step = int((parent_obj_l / detection_w) + 0.99)
                detection_w = parent_obj_l / step
                for num in range(step):
                        scan_base_pose_1 = Pose2D()
                        scan_base_pose_1.x = parent_obj_x - (parent_obj_w * 0.5 + rb_distance) * math.cos(parent_obj_th) - (0.5 * parent_obj_l - 0.5 * detection_w - num * detection_w) * math.sin(parent_obj_th)
                        scan_base_pose_1.y = parent_obj_y - (parent_obj_w * 0.5 + rb_distance) * math.sin(parent_obj_th) + (0.5 * parent_obj_l - 0.5 *  detection_w - num * detection_w) * math.cos(parent_obj_th)
                        scan_base_pose_1.theta = parent_obj_th + math.pi
                        if scan_base_pose_1.theta > math.pi:
                                scan_base_pose_1.theta -= 2.0 * math.pi
                        elif scan_base_pose_1.theta < -math.pi:
                                scan_base_pose_1.theta += 2.0 * math.pi
                        scan_base_pose_list_1.append(scan_base_pose_1)

                #rospy.loginfo(scan_base_pose_list_1)
                
                                
                for num in range(int((parent_obj_l / detection_w) + 0.99)):
                        scan_base_pose_2 = Pose2D()
                        scan_base_pose_2.x = parent_obj_x + (parent_obj_w * 0.5 + rb_distance) * math.cos(parent_obj_th) + (0.5 * parent_obj_l - 0.5 * detection_w - num * detection_w) * math.sin(parent_obj_th)
                        scan_base_pose_2.y = parent_obj_y + (parent_obj_w * 0.5 + rb_distance) * math.sin(parent_obj_th) - (0.5 * parent_obj_l - 0.5 * detection_w - num * detection_w) * math.cos(parent_obj_th)
                        scan_base_pose_2.theta = parent_obj_th
                        if scan_base_pose_2.theta > math.pi:
                                scan_base_pose_2.theta -= 2.0 * math.pi
                        elif scan_base_pose_2.theta < -math.pi:
                                scan_base_pose_2.theta += 2.0 * math.pi
                        scan_base_pose_list_2.append(scan_base_pose_2)



                step = int((parent_obj_w / detection_w) + 0.99)
                detection_w = parent_obj_w / step               
                for num in range(step):
                        scan_base_pose_3 = Pose2D()
                        scan_base_pose_3.x = parent_obj_x + (parent_obj_l * 0.5 + rb_distance) * math.sin(parent_obj_th) - (0.5 * parent_obj_w - 0.5 * detection_w - num * detection_w) * math.cos(parent_obj_th)
                        scan_base_pose_3.y = parent_obj_y - (parent_obj_l * 0.5 + rb_distance) * math.cos(parent_obj_th) - (0.5 * parent_obj_w - 0.5 *  detection_w - num * detection_w) * math.sin(parent_obj_th)
                        scan_base_pose_3.theta = parent_obj_th - 0.5 * math.pi
                        if scan_base_pose_3.theta > math.pi:
                                scan_base_pose_3.theta -= 2.0 * math.pi
                        elif scan_base_pose_3.theta < -math.pi:
                                scan_base_pose_3.theta += 2.0 * math.pi
                        scan_base_pose_list_3.append(scan_base_pose_3)

                


                for num in range(step):
                        scan_base_pose_4 = Pose2D()
                        scan_base_pose_4.x = parent_obj_x - (parent_obj_l * 0.5 + rb_distance) * math.sin(parent_obj_th) + (0.5 * parent_obj_w - 0.5 * detection_w - num * detection_w) * math.cos(parent_obj_th)
                        scan_base_pose_4.y = parent_obj_y + (parent_obj_l * 0.5 + rb_distance) * math.cos(parent_obj_th) + (0.5 * parent_obj_w - 0.5 * detection_w - num * detection_w) * math.sin(parent_obj_th)
                        scan_base_pose_4.theta = parent_obj_th + 0.5 * math.pi
                        if scan_base_pose_4.theta > math.pi:
                                scan_base_pose_4.theta -= 2.0 * math.pi
                        elif scan_base_pose_4.theta < -math.pi:
                                scan_base_pose_4.theta += 2.0 * math.pi
                        scan_base_pose_list_4.append(scan_base_pose_4)

        #the short side is facing the robot     
        else:
                parent_obj_th -= 0.5 * math.pi
                step = int((parent_obj_w / detection_w) + 0.99)
                detection_w = parent_obj_w / step
                for num in range(step):
                        scan_base_pose_1 = Pose2D()
                        scan_base_pose_1.x = parent_obj_x - (parent_obj_l * 0.5 + rb_distance) * math.cos(parent_obj_th) - (0.5 * parent_obj_w - 0.5 * detection_w - num * detection_w) * math.sin(parent_obj_th)
                        scan_base_pose_1.y = parent_obj_y - (parent_obj_l * 0.5 + rb_distance) * math.sin(parent_obj_th) + (0.5 * parent_obj_w - 0.5 *  detection_w - num * detection_w) * math.cos(parent_obj_th)
                        scan_base_pose_1.theta = parent_obj_th + math.pi
                        if scan_base_pose_1.theta > math.pi:
                                scan_base_pose_1.theta -= 2.0 * math.pi
                        elif scan_base_pose_1.theta < -math.pi:
                                scan_base_pose_1.theta += 2.0 * math.pi
                        scan_base_pose_list_1.append(scan_base_pose_1)
        
                                
                for num in range(step):
                        scan_base_pose_2 = Pose2D()
                        scan_base_pose_2.x = parent_obj_x + (parent_obj_l * 0.5 + rb_distance) * math.cos(parent_obj_th) + (0.5 * parent_obj_w - 0.5 * detection_w - num * detection_w) * math.sin(parent_obj_th)
                        scan_base_pose_2.y = parent_obj_y + (parent_obj_l * 0.5 + rb_distance) * math.sin(parent_obj_th) - (0.5 * parent_obj_w - 0.5 * detection_w - num * detection_w) * math.cos(parent_obj_th)
                        scan_base_pose_2.theta = parent_obj_th
                        if scan_base_pose_2.theta > math.pi:
                                scan_base_pose_2.theta -= 2.0 * math.pi
                        elif scan_base_pose_2.theta < -math.pi:
                                scan_base_pose_2.theta += 2.0 * math.pi
                        scan_base_pose_list_2.append(scan_base_pose_2)


                
                step = int((parent_obj_l / detection_w) + 0.99)
                detection_w = parent_obj_l / step
                for num in range(step):
                        scan_base_pose_3 = Pose2D()
                        scan_base_pose_3.x = parent_obj_x + (parent_obj_w * 0.5 + rb_distance) * math.sin(parent_obj_th) - (0.5 * parent_obj_l - 0.5 * detection_w - num * detection_w) * math.cos(parent_obj_th)
                        scan_base_pose_3.y = parent_obj_y - (parent_obj_w * 0.5 + rb_distance) * math.cos(parent_obj_th) - (0.5 * parent_obj_l - 0.5 *  detection_w - num * detection_w) * math.sin(parent_obj_th)
                        scan_base_pose_3.theta = parent_obj_th - 0.5 * math.pi
                        if scan_base_pose_1.theta > math.pi:
                                scan_base_pose_1.theta -= 2.0 * math.pi
                        elif scan_base_pose_1.theta < -math.pi:
                                scan_base_pose_1.theta += 2.0 * math.pi
                        scan_base_pose_list_3.append(scan_base_pose_3)

                

                                
                for num in range(step):
                        scan_base_pose_4 = Pose2D()
                        scan_base_pose_4.x = parent_obj_x - (parent_obj_w * 0.5 + rb_distance) * math.sin(parent_obj_th) + (0.5 * parent_obj_l - 0.5 * detection_w - num * detection_w) * math.cos(parent_obj_th)
                        scan_base_pose_4.y = parent_obj_y + (parent_obj_w * 0.5 + rb_distance) * math.cos(parent_obj_th) + (0.5 * parent_obj_l - 0.5 * detection_w - num * detection_w) * math.sin(parent_obj_th)
                        scan_base_pose_4.theta = parent_obj_th + 0.5 * math.pi
                        if scan_base_pose_1.theta > math.pi:
                                scan_base_pose_1.theta -= 2.0 * math.pi
                        elif scan_base_pose_1.theta < -math.pi:
                                scan_base_pose_1.theta += 2.0 * math.pi
                        scan_base_pose_list_4.append(scan_base_pose_4)
                
        #rospy.loginfo(scan_base_pose_list_1)
        #rospy.loginfo(scan_base_pose_list_2)
        #rospy.loginfo(scan_base_pose_list_3)
        #rospy.loginfo(scan_base_pose_list_4)
        
        #obstacle check
        obstacle_checked_scan_base_pose_list_1 = obstacleCheck(scan_base_pose_list_1, furniture_geometry_list, parent_obj_x, parent_obj_y)
        obstacle_checked_scan_base_pose_list_2 = obstacleCheck(scan_base_pose_list_2, furniture_geometry_list, parent_obj_x, parent_obj_y)
        obstacle_checked_scan_base_pose_list_3 = obstacleCheck(scan_base_pose_list_3, furniture_geometry_list, parent_obj_x, parent_obj_y)
        obstacle_checked_scan_base_pose_list_4 = obstacleCheck(scan_base_pose_list_4, furniture_geometry_list, parent_obj_x, parent_obj_y)



        #rospy.loginfo([obstacle_checked_scan_base_pose_list_1, obstacle_checked_scan_base_pose_list_2, obstacle_checked_scan_base_pose_list_3, obstacle_checked_scan_base_pose_list_4])
        max_len = max(len(obstacle_checked_scan_base_pose_list_1), len(obstacle_checked_scan_base_pose_list_2), len(obstacle_checked_scan_base_pose_list_3), len(obstacle_checked_scan_base_pose_list_4))

        #choose the longest scan pose list 
        if len(obstacle_checked_scan_base_pose_list_1) == max_len:
                scan_base_pose_list = [obstacle_checked_scan_base_pose_list_1]
        elif len(obstacle_checked_scan_base_pose_list_2) == max_len:
                scan_base_pose_list = [obstacle_checked_scan_base_pose_list_2]
        elif len(obstacle_checked_scan_base_pose_list_3) == max_len:
                scan_base_pose_list = [obstacle_checked_scan_base_pose_list_3]
        else:
                scan_base_pose_list = [obstacle_checked_scan_base_pose_list_4]
        

        if not scan_base_pose_list:
                print "no valid scan pose."

        
        return scan_base_pose_list



def symbol_grounding_scan_base_pose_server():
        rospy.init_node('symbol_grounding_scan_base_pose_server')
        s = rospy.Service('symbol_grounding_scan_base_pose', SymbolGroundingScanBasePose, handle_symbol_grounding_scan_base_pose)
        print "Ready to receive requests."
        rospy.spin()



if __name__ == "__main__":
    symbol_grounding_scan_base_pose_server()