converting a bag file to images

rosbag

asked 2011-04-27 10:08:13 -0500

Lee Redden
76 ●2 ●2 ●5

updated 2011-04-29 08:46:31 -0500

I am following the tutorial here for exporting images from a bag file to jpegs. http://www.ros.org/wiki/rosbag/Tutori...

when I run rosbag info BAGFILE I get rosbag info 2011-02-08-22-11-49.bag

path:        2011-02-08-22-11-49.bag
version:     2.0
duration:    13.3s
start:       Feb 08 2011 22:11:49.81 (1297231909.81)
end:         Feb 08 2011 22:12:03.15 (1297231923.15)
size:        235.6 MB
messages:    201
compression: none [201/201 chunks]
types:       sensor_msgs/Image [060021388200f6f0f447d0fcd9c64743]
topics:      /down_camera/camera/image_raw   201 msgs @ 15.0 Hz : sensor_msgs/Image

I have created a launch file and when I run roslaunch export.launch with this as my export file

<launch>
  <node pkg="rosbag" type="rosbag" name="rosbag" args="play -d 2 /media/Ubuntu/RosBagFiles/TestFolder/2011-02-08-22-11-49.bag"/>
  <node name="extract" pkg="image_view" type="extract_images" respawn="false" output="screen" cwd="node">
    <remap from="image" to="/down_camera/camera/image_raw"/>
  </node>
</launch>

this is what runs.

leeredden@ubuntu:/media/Ubuntu/RosBagFiles/TestFolder$ roslaunch export.launch
... logging to /home/leeredden/.ros/log/dae934d2-7113-11e0-9fd4-00216a65216e/roslaunch-ubuntu-2516.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.

started roslaunch server http://ubuntu:41180/

SUMMARY
========

NODES
  /
    rosbag (rosbag/rosbag)
    extract (image_view/extract_images)

starting new master (master configured for auto start)
process[master]: started with pid [2530]
ROS_MASTER_URI=http://ubuntu:11311/

setting /run_id to dae934d2-7113-11e0-9fd4-00216a65216e
process[rosout-1]: started with pid [2543]
started core service [/rosout]
process[rosbag-2]: started with pid [2546]
process[extract-3]: started with pid [2547]
[ INFO] [1303939092.680590263]: Initialized sec per frame to 0.100000
[ INFO] [1303939096.111425424]: Saved image frame0000.jpg
[ INFO] [1303939096.270134130]: Saved image frame0001.jpg
[ INFO] [1303939096.407313803]: Saved image frame0002.jpg
[ INFO] [1303939096.539443192]: Saved image frame0003.jpg
[ INFO] [1303939096.669743998]: Saved image frame0004.jpg
...............
[ INFO] [1303939109.207290966]: Saved image frame0098.jpg
[ INFO] [1303939109.342248572]: Saved image frame0099.jpg
[rosbag-2] process has finished cleanly.
log file: /home/leeredden/.ros/log/dae934d2-7113-11e0-9fd4-00216a65216e/rosbag-2*.log

but it doesn't seem to save the frames anywhere. I have done a sudo updatedb and locate for some of the file names but can't find them saved anywhere.

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Comments

Hi, I am doing the same thing as you did. Why do you appear to have 201 msgs on your image_raw topic and at the end when you convert you have only until 099.jpg that means 100 frames created? Thanks for your help.

fabbro ( 2016-03-16 12:02:59 -0500 )edit

Hello, if you look at "args" in the launchfile posted here you see "play -d 2". The -d means the duration, meaning that the bag file is played for 2 seconds while image_view extracts the images. This should be why there are less frames.