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Description

This package contains launch scripts which start up data acquisition from vision sensors (stereo camera systems and kinect).

Example of a stereo rig with two AVT Guppy cameras and a Microsoft Kinect on top:

Functionality

The launch system for the stereo cameras is subdivided in a hierarchy with three levels where the more specific launch files call the more generic. This is done to group common parts of monolithic launch files of different stereo systems together.

• The top level file is stereo_rig.launch in the launch/image_acquisition_pipelines directory which is used by all the setups in this package. It uses unsynced_stereo_proc.launch in the same directory, which starts a stereo_image_proc node, for the postprocessing of raw images as there is no hardware sync of the image capturing in both cameras enabled

• In the launch/image_acquisition_pipelines/stereo_rigs directory are launch scripts which more or less parametrize the top level script depending on the used hardware setup independently of user specific settings.

• The low level scripts are typically located in launch/image_acquisition_pipelines/trunk and contain the user settings for a certain setup. They load up two files which contain camera specific settings:

  • The .yaml files contain settings for the mode of a certain camera (e.g. resolution, frame rate)
  • The .ini files contain camera calibrations for a certain camera

The launch system of the kinect uses openni_launch and rgbd_launch to process the data and the scripts in launch/image_acquisition_pipelines/kinect are used to call those nodes with the correct parameters.

Usage

Needed packages

Stereo camera setup:

• stereo_image_proc

Kinect:

• openni_launch

• rgbd_launch

Needed software

libdc1394 needs to be installed for the use of stereo cameras

Needed hardware

A vision sensor setup of your choice.

Start system

For stereo cameras:

• You just need to call a single launch file of your choice to get the entire rig running together with the necessary postprocessing (see the different hierarchy levels mentioned above). By default the package contains calibrated launch files for stereo setups using AVT Marlin and Guppy cameras

For the kinect camera:

• Simply start your desired launch file, either kinect_with_registered_guppy_mild.launch or kinect_with_registered_guppy_dome.launch depending your specific environment (mild or dome) or use those files and change their parameters if you want to use your own setup. If you want a textured point cloud you need to publish a transformation between the rgb and the depth frame (e.g. asr_kinematic_chain_dome)

ROS Nodes

Subscribed Topics

Kinect camera:

• /stereo/left/camera_info: Contains the camera info of the left camera of a stereo setup, but can be supplied with the camera info of a single rgb camera as well.
• /stereo/left/image_raw: The raw left image of the stereo setup related to camera info (or from a single camera)

This is used only if you want to register an external camera and use the image of that one instead of the internal rgb-camera of the kinect.

Published Topics

Stereo camera:

• /stereo/left/camera_info: Holds the calibration for the left camera of our stereo setups (after calibration of course...).
• /stereo/left/image_raw: Image of left camera, containing raw bayer pattern, before demosaicing. Do not mix it up with the grayscale image... and don't use it directly.
• /stereo/left/image_mono: Grayscale image of left camera of stereo pair.
• /stereo/left/image_color: RGB image of left camera of stereo pair.
• /stereo/left/image_mono_rect: Grayscale image for left camera of idealized stereo setup, not our real. Required in some applications.
• /stereo/left/image_color: RGB image for right camera of idealized stereo setup, not our real. Required in some applications.
• /stereo/right/camera_info: Holds the calibration for the right camera of our stereo setups (after calibration of course...).
• /stereo/right/image_raw: Image of right camera, containing raw bayer pattern, before demosaicing. Do not mix it up with the grayscale image... and don't use it directly.
• /stereo/right/image_mono: Grayscale image of right camera of stereo pair.
• /stereo/right/image_color: RGB image of right camera of stereo pair.
• /stereo/right/image_mono_rect: Grayscale image for right camera of idealized stereo setup, not our real. Required in some applications.
• /stereo/right/image_color: RGB image for right camera of idealized stereo setup, not our real. Required in some applications.

Kinect camera (important ones only):

• /kinect/depth/image_rect: Rectified depth image from the kinect
• /kinect/depth/points: Untextured point cloud from the kinect
• /kinect/depth_registered/points: Textured point cloud from the kinect, only if the topics which are named under 'Subscribed Topics' get supplied and a transformation between the kinect and that external camera exists

Tutorials

If you want to use your own stereo camera setting, you will need to implement your own launch file(s):

1. If you simply want to use the same rig (with the same cameras) as one of the ones provided, then you only need to add a launch file to the trunk directory (or modify one of the provided launch/yaml/ini files) which includes a launch file in the hierarchy level above and use your own calibration values (see the low level part described in functionality). Check the camera_calibration tutorials on how to get those values and also check the provided launch files for more information on the structure and the used parameters.

2. In case you want to use your own cameras you will have to add a launch file to the stereo_rigs directory which includes the top level launch file (stereo_rig.launch) and add the parameters accordingly to your setup (compare the provided launch files for the guppy or marlin setup). Then again you can add a low level launch file to the trunk directory containing your camera specific calibration values.

For more information on the image processing parameters and the general functionality check out the image_proc/ stereo_image_proc packages.