Hi, I am using ROS hydro 12.04 LTS. Currently I successfully launching the motion tracking node based on openni and kinect. There is the data shown at the terminal whenever there is a motion in front of the kinect camera. However, when I look at rqt_graph , there is no published topic for that data and I am wondering why.

Can anyone suggest on how to extract those data to matlab or other program? I can share the developed package if u want to try it. Thanks for your concern.

I had tried to write a code publishing to a topic on the "blob-parameter" line below but there is an error where the global name for std_msgs not defined and error in code syntax : #!/usr/bin/env python

-- coding: utf-8 --

import rospy import sys import cv2 import cv2.cv as cv from sensor_msgs.msg import Image, CameraInfo from cv_bridge import CvBridge, CvBridgeError import numpy as np from numpy import * import os.path import time from std_msgs.msg import String

def bg_diff(fn_bg,im_in,th,blur):

im_bg = fn_bg

diff = cv2.absdiff(im_in,im_bg)

mask = diff < th

hight = im_bg.shape[0]
width = im_bg.shape[1]

im_mask = np.zeros((hight,width),np.uint8)

im_mask[mask]=255

im_mask = cv2.medianBlur(im_mask,blur)

im_edge = cv2.Canny(im_mask,100,200)


return im_bg, im_in, im_mask, im_edge

def nothing(x): pass

class bgsub2(): def __init__(self): self.node_name = "bgsub"

    rospy.init_node(self.node_name)

    self.th = rospy.get_param("~move_threshold", "60")        

    rospy.on_shutdown(self.cleanup)

    cv2.namedWindow("Motion Edge")
    cv2.createTrackbar("threshold", "Motion Edge", self.th, 255, nothing)

    self.isStart = True

    self.cv_window_name = self.node_name
    cv.NamedWindow(self.cv_window_name, cv.CV_WINDOW_NORMAL)
    cv.MoveWindow(self.cv_window_name, 25, 75)

    cv.NamedWindow("Depth Image", cv.CV_WINDOW_NORMAL)
    cv.MoveWindow("Depth Image", 25, 350)

    self.bridge = CvBridge()

    self.image_sub = rospy.Subscriber("input_rgb_image", Image, self.image_callback, queue_size=1)

    self.depth_sub = rospy.Subscriber("input_depth_image", Image, self.depth_callback, queue_size=1)        

    rospy.loginfo("Waiting for image topics...")
    rospy.wait_for_message("input_rgb_image", Image)
    rospy.wait_for_message("input_depth_image", Image)      
    rospy.loginfo("Ready.")



def image_callback(self, ros_image):

    try:
        frame = self.bridge.imgmsg_to_cv2(ros_image, "bgr8")
    except CvBridgeError, e:
        print e

    frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)        
    self.th = cv2.getTrackbarPos("threshold", "Motion Edge")       
    if self.isStart == True:
        self.frame_prev = frame
        self.isStart = False
        return 

    im_bg,im_in,im_mask,im_edge = bg_diff(self.frame_prev,frame,self.th,blur=7)       
    cv2.imshow("Input",im_in)
    cv2.imshow("Background",im_bg)      
    img_size = im_edge.shape      
    params = cv2.SimpleBlobDetector_Params()      
    params.filterByArea = True
    params.minArea = 10

Blob-parameter detector

    detector = cv2.SimpleBlobDetector(params)        
    keypoints = detector.detect(im_edge)
    print len(keypoints)
    if len(keypoints) != 0:
        ptx=0
        pty=0    
        for key in keypoints:
            ptx+=key.pt[0]
            pty+=key.pt[1]
        pt= ( int(ptx/ len(keypoints)), int(pty/ len(keypoints)))

        print pt
        self.pt = rospy.Publisher('pointer', std_msgs.msg.String, queue_size=1)

    else:
        pass

    im_edge = cv2.drawKeypoints(im_edge, keypoints, np.array([]), (0,0,255), cv2.DRAW_MATCHES_FLAGS_DRAW_RICH_KEYPOINTS)

    cv2.imshow("Motion Edge",im_edge)

    self.frame_prev = frame

    self.keystroke = cv2.waitKey(5)
    if self.keystroke != -1:
        cc = chr(self.keystroke & 255).lower()
        if cc == 'q':

            rospy.signal_shutdown("User hit q ...