vdonkey's profile - activity

In brief, I am going to use slam_gmapping with kinect. but the result is very bad. however I rotate, move the kinect, the result map in rviz just keep a fan-shaped area no more than 90 degree.

I am not even very clear about what question to ask, I feel not mastering the whole thing :(

so, maybe describe what I did in detail is a good idea. the question will be long, but easy to understand this way:

1. in ubuntu open a terminal, type

   roscore
   

2. start kinect driver in another terminal

   rosrun openni_camera openni_node
   

3. convert depth image into LaserScan

   rosrun depthimage_to_laserscan depthimage_to_laserscan image:=/depth/image_raw
   

4. run gmapping

   rosrun gmapping slam_gmapping scan:=/scan
   

5. run rviz to see result "Map", "LaserScan" and "Image"

   rosrun rviz rviz
   

I got warning message at step 2, I hope it doesn't matter because I can see a fairly good "Image" of "/depth/image_raw" topic

[ WARN] [1399535684.197109851]: ~device_id is not set! Using first device.
[ WARN] [1399535684.562974619]: Camera calibration file /home/vdonkey/.ros/camera_info/rgb_A00366913062050A.yaml not found.
[ WARN] [1399535684.563025039]: Using default parameters for RGB camera calibration.

I also got warning at step 4

[ WARN] [1399536805.888066710]: MessageFilter [target=odom ]: Dropped 100.00% of messages so far. Please turn the [ros.gmapping.message_notifier] rosconsole logger to DEBUG for more information.

this warning cannot be ignored, since I cannot see any map showed in rviz after adding a "Map" subscribing "/map" topic. so I add this before step 4

rosparam set /slam_gmapping/odom_frame camera_depth_frame

camera_depth_frame seems to be the default frame id of /scan topic published by depthimage_to_laserscan package

but after that, the warning message of gmapping changed into

[ WARN] [1399537552.284971741]: Failed to compute laser pose, aborting initialization ("base_link" passed to lookupTransform argument target_frame does not exist. )

so I added this before step 4

rosparam set /slam_gmapping/base_frame camera_depth_frame

this time I got no warning message, after setting base_frame and odom_frame, I have "Map", "LaserScan" showed in rviz.

The problem is, nevertheless I rotate/move the kinect, the result map is always facing a same direction. of course so does the laser scan lines. I have some guesses/questions:

1. maybe I need a Wheel Encoder hardware?
2. where to buy a proper wheel encoder? how to drive it?
3. what topic will wheel encoder's driver publish? while gmapping only subscribe /tf and /scan
4. topics subscribed can be regarded as input, topics published can be regarded as output, how about parameters? input? output? how about base_frame and odom_frame of gmapping ? I think they should affect "/map" topic, an output topic, so that they are some kind of output, but the two "rosparam set" before running gmapping give me hint that they are inputs.
5. why I got no warning even I didn't do anything to the /tf topic? what should I do about /tf? why I always get "no tf data received" pdf after executing "rosrun tf view_frames" even when gmapping is running?

thank you for watching this long question. I hope I can understand the ... (more)

A lot thanks to Ken, rock-ass.

Since I have succeeded in viewing 3D images in rgbdslam under your kindly help, I decide to show my commands here. I am not confident I am using ROS in the right way, but "comment" has words limit.

I am using a 3D camera with two "eyes" but only one USB line. 640x480 is the max resolution supported for single eye, but 640x480 with both eyes will not work because of USB bandwidth limit. so 352x288 is the max for stereo here.

All packages I used are: usb_cam, camera_calibration, camera_calibration_parsers, stereo_image_proc, image_view(optional), rgbdslam. usb_cam is the camera driver, and I used camera_calibration to calibrate my stereo cameras.

Open 1st terminal, run

roscore

Open 2nd terminal, run (drive the left eye)

rosparam set /stereo/left/video_device /dev/video2
rosparam set /stereo/left/image_width 352
rosparam set /stereo/left/image_height 288
rosparam set /stereo/left/pixel_format yuyv
rosparam set /stereo/left/camera_name left
rosrun usb_cam usb_cam_node /usb_cam:=/stereo/left/

Open 3rd terminal, run (drive the right eye)

rosparam set /stereo/right/video_device /dev/video1
rosparam set /stereo/right/image_width 352
rosparam set /stereo/right/image_height 288
rosparam set /stereo/right/pixel_format yuyv
rosparam set /stereo/right/camera_name right
rosrun usb_cam usb_cam_node /usb_cam:=/stereo/right/

Open 4th terminal, run (do calibration)

rosrun camera_calibration cameracalibrator.py --size 7x6 --square 0.049 left:=/stereo/left/image_raw right:=/stereo/right/image_raw left_camera:=/stereo/left right_camera:=/stereo/right --approximate=0.01 --no-service-check

notice that, before calibration, left and right camera will show warning messages saying cannot find some yaml files. that is ok at this point.

click "calibrate" button after it is enabled after taking 40 or more chessboard pictures. wait patiently. after quite a while, the calibration is done, check the epi value in top-right corner (let the camera see the chessboard again). if the epi is less than 2.5 it is acceptable, better value under 1.0. Then click "save". "commit" is a terrible button for me, because it will sometimes make my ubuntu reboot. just ignore the "commit" button.

"save" gives a /tmp/calibration.tar.gz(file name not sure). extract ost.txt out to /tmp/ost.ini, cut the ini file into two files manually half-half, for example /tmp/ost_left.ini and /tmp/ost_right.ini, then convert the ini files into yamls:

rosrun camera_calibration_parsers convert /tmp/ost_left.ini ~/.ros/camera_info/left.yaml
rosrun camera_calibration_parsers convert /tmp/ost_right.ini ~/.ros/camera_info/right.yaml

restart 2nd and 3rd terminal's command(ctrl+c and run again), this time there should be no warning messages

Open 5th terminal, run (mainly generate point cloud and disparity)

rosparam set /stereo/stereo_image_proc/approximate_sync true
ROS_NAMESPACE=stereo rosrun stereo_image_proc stereo_image_proc

the calibration must be done, or, stereo_image_proc will complain camera not calibrated

Open 6th terminal, run (showing left, right and disparity runtime images)

rosrun image_view stereo_view stereo:=stereo image:=image_rect _approximate_sync:=true

here is the chance to see disparity image, if the disparity is not good enough,it is a good idea ... (more)