[ros-users] Ranger (Sonar/IR) message added to sensor_msgs?

[Ivan Dryanovski]

I would be interested in seeing this implemented. I think a single
message type can describe both IR sensors and Sonars. A field
describing the type of radiation could be useful. For example, sonars
tend to be more sensitive to the incidence angle, so if someone is
using it for localizing, they might be interested in discriminating
between Sonar and IR.

I like the terms "spread_angle" and "fov" a little better than
"beam_angle". The latter makes it sound a little like the center angle
of the beam in some fixed frame, rather than a spread. This is a minor
issue and a matter of preference I suppose.

Another thing to consider is a convention about out-of-range readings.
If I recall correctly, LaserScan drivers currently return "0" for
out-of-range.

Ivan Dryanovski


On Sat, Oct 2, 2010 at 6:48 AM, Eric Perko <wisesage5001 at gmail.com> wrote:
> I'd like to ping the list to see if there are others that would benefit from
> a generic "Ranger" message being added to the sensor_msgs package and be
> interested in participating in a review process to get one added. An example
> use for this message type would be ultrasonic sensors or IR sensors.
> Current ROS messages similar to this (at least the ones I can find):
>
> nxt_msgs/Range (http://www.ros.org/doc/api/nxt_msgs/html/msg/Range.html)
> p2os has a SonarArray message that just contains a vector of ranges without
> min/max info or FOV angle info
>
> Information that I believe is sufficient for a range message (Note this is
> equivalent to the nxt_msgs/Range definition):
>
> Standard Header
> min/max range
> beam angle
> range reading
>
> Unless anyone needs more information in order to utilize a Sonar/IR ranger,
> I propose migrating the Range message from nxt_msgs to sensor_msgs. It would
> likely make sense to also migrate the RVIZ visualization marker for the
> ranger as well if the Range message was migrated.
> We are currently working on exposing the Ranger model in Stage to ROS and
> the message that is most appropriate is nxt_msgs/Range. I think we'd all
> agree that it doesn't make much sense for Stage to depend on nxt_msgs, so we
> need a message in the base ROS stacks to use.
> Open questions I have:
>
> Should we combine Sonars and IR sensors into one sensor_msgs/Ranger message
> or are they distinct enough to warrant completely separate messages? Is
> there enough of a difference to add some sort of type field enumerating the
> radiation used by the sensor (IR light, sound waves, etc)? I can see a use
> for knowing whether or not to expect the sensor to return from, say, glass,
> but that could also be taken care of out-of-band by knowing other info about
> the sensor.
> What to call the "beam angle"? nxt_msgs/Range calls it spread_angle, Stage
> calls it fov, and Sonar spec sheets often call it beam_angle. Is there any
> reason to prefer one over the other?
>
> Thoughts?
> - Eric
> _______________________________________________
> ros-users mailing list
> ros-users at code.ros.org
> https://code.ros.org/mailman/listinfo/ros-users
>
>