Tag Archives: Webcam

Status Update: Calibrating for Depth

Currently I am experimenting with stereo vision usb webcams, where an essential step is good calibration. It felt a bit strange to see the image feature detection working on live data:

Screenshot - 09.11.2014

I’ll try to form the gained experiences into a small step by step guide and probably a github repository soon. Currently I am aiming towards depth data gained by webcams only, especially to compare the results to previous setups, and to see if visual odometry can be an option in low cost environments.

ROS Basics – Using ROS Indigo/Jade with a Webcam by the uvc_camera (USB Video Class) package

There are several ways to use ROS Indigo/Jade with a webcam. The one way working at most computer is using a ROS package called uvc_camera which has been created by Ken Tossell. UVC in this context stands for USB Video Class, which is a  standard that covers almost all consumer webcams.

Unfortunately there currently is no step by step tutorial how to use the package, which is why I created this page. In order to run the package, you will need a local catkin workspace as we created it in another post. This is caused by the fact, that the available package is outdated and does not contain any launch files.

Step by Step Guide

We start by cloning the files into our workspace ./src directory, solving the dependencies with rosdep and finally building the workspace with catkin_make:

Before I could build my workspace with the newly cloned files, I still was required to install video4linux support libraries in their development version by:

After catkin_make finished you can launch the uvc_camera node by:

After having a roscore running, the camera_node.launch file should give you something like the following output:

where you can see the possible run modes you know can configure in your custom launch file:

You can now start rqt and its plugin Visualization > Image View, choose e.g. the /image_raw topic and in case you have club mate and a hitchhiker’s guide to the galaxy by Douglas Adams around, you’ll get the following output:

RQT Image View UVC camera