o3d3xx-ros

o3d3xx-ros is a wrapper around libo3d3xx enabling the usage of IFM Efector O3D3xx ToF cameras from within ROS software systems.

Software Compatibility Matrix

Prerequisites

1. Ubuntu 14.04 or 16.04
2. ROS Indigo or Kinetic
3. libo3d3xx

Additionally, your compiler must support C++11. This package has been validated with:

• g++ 4.8.2 on Ubuntu 14.04 LTS, ROS Indigo
• g++ 5.3.x on Ubuntu 16.04 LTS, ROS Kinetic

Building and Installing the Software

NOTE: Since we are talking about ROS here, we assume you are on Ubuntu Linux.

You should first ensure that you have installed ROS by following these instructions. The desktop-full installation is highly recommended.

Next, you should be sure to install libo3d3xx. This ROS package assumes you have installed libo3d3xx via the supported debian installer. Step-by-step instructions for that process are located here. If you already have libo3d3xx installed you can skip this step. However, it is important to point out that the table above denotes a software compatibility matrix and you should be sure to link o3d3xx-ros against a compatible version of libo3d3xx.

We now move on to building o3d3xx-ros.

Building and installing o3d3xx-ros is accomplished by utilizing the ROS catkin tool. There are many tutorials and other pieces of advice available on-line advising how to most effectively utilize catkin. However, the basic idea is to provide a clean separation between your source code repository and your build and runtime environments. The instructions that now follow represent how we choose to use catkin to build and permanently install a ROS package from source.

First, we need to decide where we want our software to ultimately be installed. For purposes of this document, we will assume that we will install our ROS packages at ~/ros. For convenience, we add the following to our ~/.bash_profile:

if [ -f /opt/ros/indigo/setup.bash ]; then
    source /opt/ros/indigo/setup.bash
fi

cd ${HOME}

export LPR_ROS=${HOME}/ros

if [ -d ${LPR_ROS} ]; then
    for i in $(ls ${LPR_ROS}); do
        if [ -d ${LPR_ROS}/${i} ]; then
            if [ -f ${LPR_ROS}/${i}/setup.bash ]; then
                source ${LPR_ROS}/${i}/setup.bash --extend
            fi
        fi
    done
fi

Next, we need to get the code from github. We assume we keep all of our git repositories in ~/dev.

$ cd ~/dev
$ git clone https://github.com/lovepark/o3d3xx-ros.git

We now have the code in ~/dev/o3d3xx-ros. Next, we want to create a catkin workspace that we can use to build and install that code from. It is the catkin philosophy that we do not do this directly in the source directory.

$ cd ~/dev
$ mkdir o3d3xx-catkin
$ cd o3d3xx-catkin
$ mkdir src
$ cd src
$ catkin_init_workspace
$ ln -s ~/dev/o3d3xx-ros o3d3xx

So, you should have a catkin workspace set up to build the o3d3xx-ros code that looks basically like:

[ ~/dev/o3d3xx-catkin/src ]
tpanzarella@jelly: $ pwd
/home/tpanzarella/dev/o3d3xx-catkin/src

[ ~/dev/o3d3xx-catkin/src ]
tpanzarella@jelly: $ ls -l
total 0
lrwxrwxrwx 1 tpanzarella tpanzarella 49 Dec  2 15:26 CMakeLists.txt -> /opt/ros/indigo/share/catkin/cmake/toplevel.cmake
lrwxrwxrwx 1 tpanzarella tpanzarella 32 Dec  2 15:24 o3d3xx -> /home/tpanzarella/dev/o3d3xx-ros

Now we are ready to build the code.

$ cd ~/dev/o3d3xx-catkin
$ catkin_make -DCATKIN_ENABLE_TESTING=ON
$ catkin_make run_tests
$ catkin_make -DCMAKE_INSTALL_PREFIX=${LPR_ROS}/o3d3xx install

The ROS package should now be installed in ~/ros/o3d3xx. To test everything out you should open a fresh bash shell, and start up a ROS core:

$ roscore

Open another shell and start the primary camera node:

$ roslaunch o3d3xx camera.launch ip:=192.168.10.69

NOTE: The IP address of your camera may differ. If you are using the factory default (192.168.0.69), you do not need to specify it on the above roslaunch line.

Open another shell and start the rviz node to visualize the data coming from the camera:

$ roslaunch o3d3xx rviz.launch

At this point, you should see an rviz window that looks something like:

Congratulations! You can now utilize o3d3xx-ros.

Nodes

/o3d3xx/camera

This node provides a real-time feed to the camera data. This node is started from the primary camera.launch file:

$ roslaunch o3d3xx camera.launch

The naming of the camera can be customized via the ns (namespace) and nn (node name) command line arguments passed to the camera.launch file. For example, if you specify your roslaunch command as:

$ roslaunch o3d3xx camera.launch ns:=robot nn:=front_camera

The node will have the name /robot/front_camera in the ROS computation graph.

Published Topics

Advertised Services

Parameters

/o3d3xx/camera_tf

This node is of type tf/static_transform_publisher. It establishes a frame_id for the camera in the global tf tree. This node is launched from the primary camera.launch file:

$ roslaunch o3d3xx camera.launch

When run as above, the tf publishing node would be named /o3d3xx/camera_tf and the camera coordinate frame would be o3d3xx/camera_link in the tf tree.

You can customize this naming via the frame_id_base arg or implicitly through the ns (namespace) and nn (node name) command line arguments passed to the camera.launch file. For example, if you specify your roslaunch command as:

$ roslaunch o3d3xx camera.launch ns:=robot nn:=front_camera

The node name will be /robot/front_camera_tf and the camera frame will be robot/front_camera_link in the tf tree.

/o3d3xx/camera/config_node

This node is used as a proxy to simplify calling the /o3d3xx/camera/Config service offered by the /o3d3xx/camera node. It was noted above that there appears to be a limitation in the YAML parser of the ROS rosservice command line tool. Specifically, it seems that it is not capable of assigning a JSON string to a variable. This is the reason for this node. This is not a long-running node but rather works like a typical command-line tool would: you invoke it, it runs, and exits. The following command line will launch this node:

$ roslaunch o3d3xx config.launch

Parameters

/rviz

This package offers a launch script that wraps the execution of rviz so that the display will be conveniently configured for visualizing the /o3d3xx/camera data. To launch this node:

$ roslaunch o3d3xx rviz.launch

Running the command as above will color the point cloud with the data from the normalized amplitude image (i.e., the intensity).

The rviz window should look something like (assuming you are coloring the point cloud with the intensity data):

/o3d3xx/camera/XXX_throttler

This package offers a launch script that wraps the topic_tools/throttler node so that it can throttle the core topics from the camera. Specifically, it will throttle /o3d3xx/camera/cloud to /o3d3xx/camera/cloud_throttle, /o3d3xx/camera/amplitude to /o3d3xx/camera/amplitude_throttle, /o3d3xx/camera/raw_amplitude_throttle, /o3d3xx/camera/depth to /o3d3xx/camera/depth_throttle, /o3d3xx/camera/confidence to /o3d3xx/camera/confidence_throttle. To launch this node:

$ roslaunch o3d3xx throttled.launch

By default, it will throttle the above named topics to 1 Hz. You can change the frequency with the hz command line argument. For example, to send data at 2 Hz:

$ roslaunch o3d3xx throttled.launch hz:=2.0

Using this launch file to launch this set of nodes is strictly optional. We have found use for it in two ways. First, to slow down the publishing frequency of the topics when used in conjunction with the /o3d3xx/camera/file_writer node for collecting data (i.e., in those instances when we really do not need all the data but rather some subsampling of it). Second, if we are running the camera on a drone (for example) that has a slower radio link down to a ground control station running rviz where we want to see what the camera sees while the drone is in flight. Clearly there are other uses for this, YMMV.

Configuring Camera Settings

Configuring the camera is accomplished by passing a JSON string to the /o3d3xx/camera/config_node which will call the /o3d3xx/camera/Config service to mutate the camera settings. Using a JSON string to configure the camera has the following primary benefits:

1. Configuration is declarative. The camera configuration will reflect that which is described by the JSON file.
2. The JSON data is human-consumable and easily edited in a text editor. This makes it very convenient for headless embedded systems.
3. The JSON data is machine parsable, so configuring the camera on the fly via programmable logic is also possible.

There are also a few downfalls to using JSON. Most notably the lack of comments and an enforceable schema. One could argue that the latter keeps things flexible. None-the-less, JSON is the format used by libo3d3xx and, by extension, this ROS package.

An exemplary JSON file is shown here (this is the result of calling the /o3d3xx/camera/Dump service on a development system). When passing a JSON string (like the previously linked to file) to the /o3d3xx/camera/Config service (or to the /o3d3xx/camera/config_node) the following rules are used to configure the camera:

1. The Device section is processed and saved on the camera.
2. The Apps section is processed. For each app:
   1. If the Index key is present, a current app at that Index is looked up. If present, it is edited to reflect the data in the JSON file. If an app at that Index is not present, a new app is created with the parameters from the JSON file. It is not guaranteed that the new app will have the specified Index.
   2. If the Index key is not present, a new app is created with the parameters as specified in the JSON file.
3. The active application is set by consulting the desired index of the ActiveApplication from the Device section of the JSON. If the specified Index does not exist, the active application is not set.
4. The Net section is processed. A reboot of the camera may be necessary after changing the camera's network parameters. Additionally, you will likely need to restart the /o3d3xx/camera node pointing it to the new IP address (if that is what you changed).

It should also be noted that any portion of the JSON tree can be specfied to configure only that part of the camera. The only rule to follow is that all keys should be fully qualified. For example, to simply set the active application, you can use a JSON snippet like this:

{
    "o3d3xx":
    {
        "Device":
        {
            "ActiveApplication": "2"
        }
    }
}

The above snippet is provided as an example here. To apply this to your camera, you can:

$ roslaunch o3d3xx config.launch infile:=/path/to/ex_set_active.json

It was also noted above that the /o3d3xx/camera/config_node will read stdin by default, so you could also:

$ echo '{"o3d3xx":{"Device":{"ActiveApplication":"2"}}}' | roslaunch o3d3xx config.launch

Here is another example JSON file. This one will add a new application to the camera, using the default values for the high-dynamic range imager. We note that this application is added to the camera because no Index is specified for the application. If an Index were specfied, the application at the specified Index, if present, would be edited to reflect this configuration.

In general, a simple way to configure camera settings without having to memorize the JSON syntax would be to simply dump the current camera settings to a file:

$ rosservice call /o3d3xx/camera/Dump > /tmp/camera.json

Then, open /tmp/camera.json with a text editor to create a declarative JSON configuration for your camera. You should be sure to delete the variable names from the rosservice output if you are following this example word-for-word. Additionally, you can delete any unnecessary keys if you would like, however it is not strictly necessary as the /o3d3xx/camera/Config service will leave unedited values unchanged on the camera. Once you have a configuration that you like, you can:

$ roslaunch o3d3xx config.launch infile:=/tmp/camera.json

You can check that your configuration is active by calling the /o3d3xx/camera/Dump service again.

TODO

Please see the Github Issues.

LICENSE

Please see the file called LICENSE.

AUTHORS

Tom Panzarella tom@loveparkrobotics.com