kinect

Stuff to get the "kinect" data published in ros, and maybe do stuff with it.

Installation

What previously was known as openni_kinect is now split into two packages: openni-camera and openni-launch. Install them:

$ sudo apt-get install ros-groovy-openni-camera ros-groovy-openni-launch

Then, you can run the process which will publish the camera's data. (Of course, roscore should be running.)

$ roslaunch openni_launch openni.launch

Viewing the topics

Check which topics are published by running rostopic list and, more interestingly, look at the streams using

$ rosrun image_view image_view image:=/camera/rgb/image_color
$ rosrun image_view image_view image:=/camera/depth/image

Troubleshooting

USB interface is not supported

Asus Xtion PRO live model 601 which is mounted on METRA robots fails to work with ROS. The solution we found on the internet is the following:

Edit the file: /etc/openni/Globaldefauts.ini (make a backup first)

find the line UsbInterface and uncomment it to force it to use 'BULK' endpoints: UsbInterface=2

We tried this already with one of the robot and it works.

Failed to set USB interface

This error may occur when executing the roslaunch openni... command.

The ASUS Xtion has firmware problems with USB 3.0 interfaces. Befor trying to patch the firmware (on Windows), just plug it into some other USB interface. Modern laptops have some USB 3.0 and some USB 2.0 interfaces, so you might be lucky to hit a 2.0 one which just works.

Another possible solution, reported to work for some, is to load the following kernel modules:

$ sudo modprobe -r gspca_kinect
$ sudo modprobe -r gspca_main

Creating a C++ node listening to the Kinect

Let's get going! I'll use $WORKSPACE to be your workspace folder.

Creating a new project in ROS

Disclaimer

I don't know all the terminologies yet, I may use wrong words for things.

Creating a package

First, creating a package:

$ cd $WORKSPACE/src
$ catkin_create_pkg vision roscpp
$ cd $WORKSPACE
$ catkin_make

There can be many "nodes" (apps/mains/...) in one package. A node may be written in C++ or Python.

Creating a C++ node

Write your code. Minimal code, in a file we'll call test_ir.cpp just for giggles, and place it into the $WORKSPACE/src/vision folder:

#include <iostream>

#include <ros/ros.h>

int main(int argc, char* argv[])
{
    ros::init(argc, argv, "Foo_bar_baz_quux");

    std::cout << "Oh hai there!" << std::endl;

    return 0;
}

Add this thingy to the CMakeLists.txt file of your package, so that catkin_make knows what to do. The previous step involving catkin_create_pkg did create a template CMakeLists.txt file in $WORKSPACE/src/vision which you can have a look at and uncomment the things you want. For our minimal project that results in:

cmake_minimum_required(VERSION 2.8.3)
project(vision)

find_package(catkin REQUIRED roscpp)

catkin_package(
    INCLUDE_DIRS include
)

include_directories(include
    ${catkin_INCLUDE_DIRS}
)

add_executable(test_ir_node test_ir.cpp)

target_link_libraries(test_ir_node
  ${catkin_LIBRARIES}
)

install(TARGETS test_ir_node
  ARCHIVE DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
  LIBRARY DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
  RUNTIME DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
)

Then, you need to compile your package by running catkin_make. But be wary, you'll get a (descriptive) error message if you run it in the wrong folder. Run it from $WORKSPACE. You might need to source $WORKSPACE/devel/setup.bash before proceeding.

If it all succeeds, you can run the test_ir_node executable/node in the vision package by then typing:

$ rosrun vision test_ir_node

It should greet you warmly.