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Hi Marcus,<br>
<br>
I haven't thought through use cases very much but one application
would be creating a library of human gestures and poses that the
robot can learn to recognize. The only reason I created a Skeleton
message type for my pi_tracker package is that I wanted to have
access to the joint confidence values. Otherwise, I think the
standard ROS tf/tfMessage type comes close.<br>
<br>
In the meantime, and just for fun, I have created a skeleton_markers
package at:<br>
<br>
<a class="moz-txt-link-freetext" href="http://www.ros.org/wiki/skeleton_markers">http://www.ros.org/wiki/skeleton_markers</a><br>
<br>
This allows the visualization of the tracked joints in RViz. There
are two ways to run the package--two different Python scripts: one
is used with pi_tracker and subscribes to the skeleton message
topic. The other uses just the transforms published by the
openni_tracker package. See the Wiki page for details. Here is a
short video of the result:<br>
<br>
<a class="moz-txt-link-freetext" href="http://www.youtube.com/watch?v=nTRi_kIgGW0">http://www.youtube.com/watch?v=nTRi_kIgGW0</a><br>
<br>
--patrick<br>
<br>
On 03/26/2011 03:27 PM, Marcus Liebhardt wrote:
<blockquote
cite="mid:AANLkTi=4nMHCpUsd4dFR=5ivtPcAWaH2MfFdo0+cVuFs@mail.gmail.com"
type="cite">Hi there!<br>
<br>
That indeed looks like a tree to me.<br>
I would be interested in the use cases you have in mind for these
skeleton messages.<br>
What information would you like to gather in those messages?<br>
Poses of the tracked frames, interconnections of each frame, also
distances between the connected frames?<br>
<br>
I don't have deep knowledge about the processing of the KInect or
the openni_tracker. I'm currently just using the transforms. But I
think there are simplifications made for some frames, which could
be useful to take into account. For example, I think the neck is
always half way between the left and right shoulder, and the head
is always on top of it. Things like that might be interesting as
well to keep in the message, so that one can easily reproduce the
previously mentioned skeleton - if that is one of the use cases.<br>
<br>
Best regards,<br>
<br>
:-) Marcus<br>
<br>
<br>
<br>
<div class="gmail_quote">2011/3/26 Patrick Goebel <span dir="ltr"><<a
moz-do-not-send="true" href="mailto:patrick@pirobot.org"
target="_blank">patrick@pirobot.org</a>></span><br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
0.8ex; border-left: 1px solid rgb(204, 204, 204);
padding-left: 1ex;">
<div text="#000000" bgcolor="#ffffff"> I see what you
mean--the user looks more like a cactus than a tree. :)))
However, I think if you take the torso joint as the root,
don't you end up with a tree structure? e.g.<br>
<br>
torso->neck->head<br>
torso->left_shoulder->left_elbow->left_hand<br>
torso->right_shoulder->right_elbow->right_hand<br>
torso->left_hip->left_knee->left_foot<br>
torso->right_hip->right_knee->right_foot<br>
<br>
Maybe this is what you meant by it depends on how you define
them.<br>
<font color="#888888"> <br>
--patrick</font>
<div>
<div><br>
<br>
On 03/26/2011 12:22 PM, David Lu!! wrote:
<blockquote type="cite">It depends on how you define
them. The skeleton visualized with the kinect ( <a
moz-do-not-send="true"
href="http://www.ros.org/wiki/openni_tracker?action=AttachFile&do=get&target=nite.png"
target="_blank">http://www.ros.org/wiki/openni_tracker?action=AttachFile&do=get&target=nite.png</a>)
isn't a tree, although it could be converted to be
one, I suppose <br>
<br>
<div class="gmail_quote">On Sat, Mar 26, 2011 at 1:11
PM, Patrick Goebel <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:patrick@pirobot.org"
target="_blank">patrick@pirobot.org</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt
0pt 0pt 0.8ex; border-left: 1px solid rgb(204,
204, 204); padding-left: 1ex;">
<div text="#000000" bgcolor="#ffffff"> Hi David,<br>
<br>
I agree it would be nice to have a standardized
Skeleton message. If all skeleton's are trees
(is this true?) then perhaps an existing tree
message type could be used if it exists. KDL
has kinematic chains and tf is already built
around trees (right?). That's about as far as
I've thought it through...<br>
<br>
--patrick
<div>
<div><br>
<br>
On 03/22/2011 04:17 PM, David Lu!! wrote: </div>
</div>
<blockquote type="cite">
<div>
<div>Hey Ros-users-
<div><br>
</div>
<div>Has there been any talk of creating a
standardized Skeleton message? Right
now, it seems like the openni_tracker
package just publishes transforms. It
seems like if the Kinect does skeleton
tracking, there should be a skeleton
message. </div>
<div><br>
</div>
<div>I know pi_tracker has its own
Skeleton message, which looks like it
might fit the bill, although I don't
think it defines which parts are
connected (hip bone is connected to the
thigh bone). </div>
<div> <a moz-do-not-send="true"
href="http://www.ros.org/doc/api/pi_tracker/html/msg/Skeleton.html"
target="_blank">http://www.ros.org/doc/api/pi_tracker/html/msg/Skeleton.html</a></div>
<div><br>
</div>
<div>It might be good to have for not only
the Kinect, but for other motion capture
rigs (Vicon and the like). </div>
<div><br>
</div>
<div>Are there any other similar message
out there?</div>
<div><br>
</div>
<div>-David!!</div>
</div>
</div>
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