Po-Jen Lai's profile - activity

I want to get the depth data from kinect by receiving sensor_msgs/Image from topic /camera/depth_registrered/image_raw(reference), I use cv_bridge to store the data to a gray scale image.

I use this snippet of code to receive sensor_msgs/Image from topic /camera/depth_registrered/image_raw, change it to gray scale image by cvBridge, and then store the image to a jpeg file.

#!/usr/bin/env python
import roslib
roslib.load_manifest('store_stereo_image')
import sys 
import rospy
import cv
from std_msgs.msg import String
from sensor_msgs.msg import Image
from cv_bridge import CvBridge, CvBridgeError

class image_converter:

  def __init__(self):
    self.bridge = CvBridge()
    self.image_sub = rospy.Subscriber("/camera/depth_registered/image_raw",Image,self.callback)

  def callback(self,data):
    try:
        cv_image = self.bridge.imgmsg_to_cv(data, "mono8")
        cv.SaveImage("depth_camera_msg.jpg", cv_image)
        print "image saved!"
    except CvBridgeError, e:
      print e

def main(args):
  ic = image_converter()
  rospy.init_node('image_converter', anonymous=True)
  try:
    rospy.spin()
  except KeyboardInterrupt:
    print "Shutting down"

if __name__ == '__main__':
    main(sys.argv)

This is the jpeg file I stored, I suppose the value in this picture should vary from 0 to 255. However, I found the values in this picture are either 0 or 255(only black and white).

I use rostopic echo /camera/depth_registered/image_raw to check, I found that the data it published vary from 0~255, but I don't know why the image is only black and white~

Did I miss something? Thanks in advance.

---EDIT---

Thanks to DamienJadeDuff's comment, I learned that the raw data from msg sensor_msgs/Image is uint8, and the data contained in /camera/depth_registered/image_raw is uint16 depths in mm. Does this means depth data is retrieved from combining two uint8 data?

Dear all, I got an import error from executing roslaunch pr2_gazebo pr2_no_controllers.launch:

ros@ros-K401UB:~/research/gps$ roslaunch pr2_gazebo pr2_no_controllers.launch 
... logging to /home/ros/.ros/log/751a586e-bd85-11e7-a646-9c5c8ed99f00/roslaunch-ros-K401UB-4556.log
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

Traceback (most recent call last):
  File "/opt/ros/indigo/share/xacro/xacro.py", line 60, in <module>
    import xacro
  File "/opt/ros/indigo/lib/python2.7/dist-packages/xacro/__init__.py", line 36, in <module>
    import glob
ModuleNotFoundError: No module named 'glob'

while processing /opt/ros/indigo/share/pr2_description/robots/upload_pr2.launch:
Invalid <param> tag: Cannot load command parameter [robot_description]: command [/opt/ros/indigo/share/xacro/xacro.py '/opt/ros/indigo/share/pr2_description/robots/pr2.urdf.xacro'] returned with code [1]. 

Param xml is <param command="$(find xacro)/xacro.py '$(find pr2_description)/robots/pr2.urdf.xacro'" name="robot_description"/>
The traceback for the exception was written to the log file

However, I can import glob in python2.7:

ros@ros-K401UB:~/research/gps$ python2.7
Python 2.7.6 (default, Oct 26 2016, 20:30:19) 
[GCC 4.8.4] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import glob
>>>

Also, I can locate it under /usr/lib/python2.7:

ros@ros-K401UB:/usr/lib/python2.7$ ls | grep glo
glob.py
glob.pyc

Thus, I guess that the problem occurs because the python executable which runs xacro.py can't locate the module glob in its path. So I tried to append /usr/lib/python2.7 to my PYTHONPATH, but this doesn't work.

Does anyone know how to solve this issue? Thanks for any suggestion : )

P.S. I am using Ubuntu 14.04+ROS Indigo, and my python -m site output this:

ros@ros-K401UB:~/research/gps$ python -m site
sys.path = [
    '/home/ros/research/gps',
    '/home/ros/research/tool/rllab',
    '/opt/ros/indigo/lib/python2.7/dist-packages',
    '/usr/lib/python2.7/dist-packages',
    '/home/ros/miniconda3/lib/python36.zip',
    '/home/ros/miniconda3/lib/python3.6',
    '/home/ros/miniconda3/lib/python3.6/lib-dynload',
    '/home/ros/miniconda3/lib/python3.6/site-packages',
    '/home/ros/code/gym',
    '/home/ros/miniconda3/lib/python3.6/site-packages/setuptools-27.2.0-py3.6.egg',
]
USER_BASE: '/home/ros/.local' (exists)
USER_SITE: '/home/ros/.local/lib/python3.6/site-packages' (doesn't exist)
ENABLE_USER_SITE: True

Reference:

1. http://forum.erlerobotics.com/t/solve...
2. https://stackoverflow.com/questions/4...

Based on the advice from jarvisschultz & bpinaya, I removed the miniconda/anaconda part in ~/.basrc: # added by Min

Based on the advice from jarvisschultz & bpinaya, I removed the miniconda/anaconda part in ~/.basrc: # added by Min

Thanks to both of you jarvisschultz & bpinaya!!! The problem is caused by miniconda, I'll leave the result in the an

Import error: No module named 'glob' Dear all, I got an import error from executing roslaunch pr2_gazebo pr2_no_controll

Import error: No module named 'glob' Dear all, I got an import error from executing roslaunch pr2_gazebo pr2_no_controll

Hi! I cannot reproduce your problem. There seems no turtlebot_empty_world.launch in turtlebot_gazebo package: https://gi

Hi! I cannot reproduce your problem. There seems no turtlebot_empty_world.launch in turtlebot_gazebo paxkage. https://g

Hi all,

The roslaunch page says that we can remap topic by simply adding this line to launch file.

<remap from="chatter" to="hello"/>

I want to ask if we can do the same thing in command line?

roslaunch <package name> <launch file name> chatter:=hello

Thanks~

Hi all,

I want to test the function of tabletop_segmentation.But when my node send a service request to /tabletop_segmentation, I always get messages indicate that "NO_CLOUD_RECEIVED".

[ INFO] [1355922807.919213857, 1093.482000000]: Tabletop detection service called; waiting for a point_cloud2 on topic /narrow_stereo_textured/points2
[ERROR] [1355922813.224946787, 1096.538000000]: Tabletop object detector: no point_cloud2 has been received

The problem is /tabletop_segmentation node receive no data from /narrow_stereo_textured/points2.(This topic exists, though)

To test /narrow_stereo_textured/points2, I started gazebo by

  roslaunch manipulation_worlds pr2_table_object.launch

And I use rviz to see what /narrow_stereo_textured/points2 published, and I can see the content by changing Fixed frame from /map to /head_mount_kinect_ir_frame.

However, when I try to rostopic echo this topic, I got

rosfuerte@rosfuerte-K53SM:~/project/nlp/libsvm-3.14$ rostopic echo /narrow_stereo_textured/points2
WARNING: no messages received and simulated time is active.
Is /clock being published?

And the segmentation fails as usual, does anyone know how to solve this problem? I want to test the function of segmentation alone. Thanks.

EDIT: This problem doesn't occur on another computer, which is also fuerte on ubuntu 12.04. I tried sudo apt-get dist-upgrade but I still got the error.

The key is to find which node want this tf relationship.

The message is complaining that canTransform() is not able to get the relationship of simplebot/base_link to /map. This is because you only have a frame called "base_link" instead of "simplebot/base_link".

So modify your code by changing the arguments of canTransform().

There are some backup files in other people's repo:

https://github.com/limhyon/vslam

https://github.com/rhuitl/vslam

Do you really got the executable when catkin_make?