11. SUPPLIED SOFTWARE
/ This virtual device provides a multi-part data stream which contains all the
data that is available through the other devices. In the default congu-
ration, this device provides the left camera image, the disparity map and
the 3D point cloud.
The virtual devices /left, /right and /disparity deliver the unprocessed data
that is received from SceneScan. The data obtained through the /pointcloud
device is computed by the producer from the received disparity map. This is
done by multiplying the disparity map with the disparity-to-depth mapping
matrix
q
(see Section 8.2), which is transmitted by SceneScan along with each
image pair. Invalid disparities are set to the minimum disparity and thus result
in points with very large distances.
It is recommended to use the multi-part virtual device / when more than
one type of data is required. This will guarantee that all data acquisition is
synchronized. When requiring only one type of input data, then using the
dedicated virtual devices is the most ecient option.
11.2.3 Device IDs
All device IDs that are assigned by the producer are URLs and consist of the
following components:
protocol :// address / virtual device
The protocol component identies the underlying transport protocol that
shall be used for communication. The following values are possible:
udp: Use the connection-less UDP transport protocol for communication.
tcp: Use the connection oriented TCP transport protocol for communication.
The virtual device shall be set to one of the device names that have been
listed in the previous section. Some examples for valid device IDs are:
udp ://192.168.10.10/ pointcloud
tcp ://192.168.10.100/ left
11.3 ROS Node
For integrating SceneScan with the Robot Operating System (ROS), there ex-
ists an ocial ROS node. This node is called nerian_stereo and can be found
in the ocial ROS package repository. The node publishes the computed dis-
parity map and the corresponding 3D point cloud as ROS topics. Furthermore,
it can publish camera calibration information.
To install this node from the ROS package servers on a Ubuntu Linux
system, please use the following commands:
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