extract_head_cloud.py

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#!/usr/bin/env python

import rospy
from sensor_msgs.msg import RegionOfInterest, Image, CameraInfo
import message_filters
from cv_bridge import CvBridge, CvBridgeError
from geometry_msgs.msg import PolygonStamped, Point32, PointStamped
import numpy as np
import dynamic_reconfigure.client
from threading import RLock
import contextlib # get rid of this once PR2 moves to python 2.7
from rospy.service import ServiceException

class Extract(object):
        bridge = CvBridge()

        xfilter = dynamic_reconfigure.client.Client('xfilter')
        yfilter = dynamic_reconfigure.client.Client('yfilter')
        zfilter = dynamic_reconfigure.client.Client('zfilter')
        
        depth_im = None
        roi      = None

        image_lock = RLock()
        roi_lock   = RLock()
        
        K = []

        def __init__(self):
                roi_sub   = rospy.Subscriber('roi', RegionOfInterest, self.roi_cb)
                depth_sub = message_filters.Subscriber('depth_image', Image)
                info_sub  = message_filters.Subscriber('camera_info', CameraInfo)
                
                ts = message_filters.TimeSynchronizer([depth_sub, info_sub], 10)
                ts.registerCallback(self.depth_cb);
                
                r = rospy.Rate(10)
                while not rospy.is_shutdown() and not self.roi and not self.depth_im:
                        r.sleep()
                while not rospy.is_shutdown():
                        self.update_params()
                        r.sleep()

        def roi_cb(self, msg):
                with self.roi_lock:
                        self.roi = msg

        def depth_cb(self, depth_msg, info_msg):
                with self.image_lock:
                        self.depth_im = self.bridge.imgmsg_to_cv(depth_msg, '32FC1')
                        self.K = info_msg.K

        def update_params(self):
                with contextlib.nested(self.roi_lock, self.image_lock):
                        if self.depth_im and self.roi:
                                x = self.roi.x_offset
                                y = self.roi.y_offset
                                w = self.roi.width
                                h = self.roi.height
                                
                                depth = self.depth_im[y+h/2,x+w/2]

                                face_center_img = np.array((x+w/2.0, y+h/2))
                                face_center_pt  = (face_center_img - (self.K[2], self.K[5])) / np.array([self.K[0], self.K[4]])
                                face_center_depth = self.depth_im[face_center_img]
                                
                                try:
                                        self.xfilter.update_configuration({
                                                'filter_field_name': 'x',
                                                'filter_limit_min': face_center_pt[0]-0.2,
                                                'filter_limit_max': face_center_pt[0]+0.2
                                        })

                                        self.yfilter.update_configuration({
                                                'filter_field_name': 'y',
                                                'filter_limit_min': face_center_pt[1]-0.2,
                                                'filter_limit_max': face_center_pt[1]+0.2
                                        })

                                        self.zfilter.update_configuration({
                                                'filter_field_name': 'z',
                                                'filter_limit_min': depth-0.2,
                                                'filter_limit_max': depth+0.2
                                        })
                                except ServiceException:
                                        rospy.logwarn("Service exception with dynamic reconfigure")
                        

if __name__ == '__main__':
        rospy.init_node('extract_head_cloud')
        Extract()
        rospy.spin()