openni_imgrect_to_shm.py

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#!/usr/bin/env python

import rospy
import os
from sensor_msgs.msg import Image

'''
rostopic info /camera/depth/image_rect
Type: sensor_msgs/Image

rosmsg show sensor_msgs/Image
std_msgs/Header header
  uint32 seq
  time stamp
  string frame_id
uint32 height
uint32 width
string encoding
uint8 is_bigendian
uint32 step
uint8[] data
'''

def imgrect_callBack(data):
        lockfilepath = "/run/shm/xtion.raw.lock"
        framefilepath ="/run/shm/xtion.raw"
        
        if os.path.exists(lockfilepath):
                return
        
        open(lockfilepath, 'w') # creates lockfile
         
        framefile = open(framefilepath, 'w')
        framefile.write(data.data)
        framefile.close()

        if os.path.exists(lockfilepath):
                os.remove(lockfilepath)
         
        # print data.width  # yeilds 640 default
        # print data.is_bigendian # yeilds 0 default
        # print data.encoding # yeilds 32FC1
        # rospy.signal_shutdown("shutdown")
        

rospy.init_node('openni_imgrect_to_shm', anonymous=False)
rospy.Subscriber("camera/depth/image_raw", Image, imgrect_callBack)

rospy.spin()