ROS package for locating small objects in space. The package combines the openni kinect driver with the ros_numpy package and uses a simple tripple integrator model with a Kalman filter and some additional tricks to estimate the position and velocities for the object. The software was used to successfully fly the very small Crazyflie 2.0 quadcopter [1] with state feedback from the kinect, and is easily integratable into any low budget robotics project. A brief demonstration of performance and the mathematics involved can be found in the /documentation directory.
- Automatic calibration and recalibration of the background and camera angle, done using one of two methods. The first uses polyfit and other utilises the singular value decomposition for plane 3D-fitting.
- Publishes the raw position of the object optionally the Kalman filtered position and velocities of the object only using prediction when a bad measurement is registered. Data is published at a rate of 30 Hz.
- Configuration files which can be used to save and load system wide settings.
- Optional live plotting of background image and estimated position.
- The openni_launch driver [2].
- The numpy_ros package [3].
- Ubuntu 14.04 Trusty [4] with a ROS Indigo installation [5]*.
- A Microsoft Kinect or a PrimeSense PSDK oran ASUS Xtion Pro and Pro Live.
*The project could potentially be run with with other versions of Ubuntu and other ROS distros supported in the openni_launch package, but this has yet to be verified.
Simply follow the installation instructions for installing ROS indigo and follow the tutorial to set up the catkin workspace [5]. Next, clone the repositories with the openni_launch (or alternatively openni2_launch) and the numpy_ros package and place the packages in the ~/catkin_ws/src/ dir3ctory. Clone the kinect_vision repo and place the entire project in ~/catkin_ws/src/. Finally, cd to ~/catkin_ws and run
`$ catkin_init`
When connecting the camera, the entire project is launched by the command
`$ roslaunch kinect_vision kinect.launch`
If the openni driver unable to run, two common reasons are that (1) the global default file is configured wrong or (2) the camera is incompatible with the openni driver, in which case the openni2 package can be tried [6].
The first problem can be usually solved by running
`$ sudo nano /etc/openni/GlobalDefaults.ini`
and then changing the settings of the variable UsbInterface=X, such that UsbInterface=2. Some have reported this variable being set to X=0 by default, and others have had it commented out (then written ;UsbInterface=X).