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<div class="moz-cite-prefix">Hi and welcome Evangelos,<br>
<br>
i'm not sure what the revived time should be. Maybe this is a
deprecated feature of the logging.<br>
The Time stamps are created in different ways. Sometimes the are
set from a camera itself. sometime from the driver.<br>
I assume (without logging into the code) that the camera-firewire
creates the timestamp when the driver received it.<br>
<br>
Because of the scheduling they cannot be the same. If you are
using a fixed-freqency you should consider the TimestampEstimater,
it eliminates several aspects.<br>
<a class="moz-txt-link-freetext" href="http://rock-robotics.org/stable/documentation/data_processing/timestamping.html">http://rock-robotics.org/stable/documentation/data_processing/timestamping.html</a><br>
<br>
The idea of syncronizing times in rock is done by the
stream-aligner.<br>
<a class="moz-txt-link-freetext" href="http://rock-robotics.org/stable/documentation/data_processing/stream_aligner.html">http://rock-robotics.org/stable/documentation/data_processing/stream_aligner.html</a><br>
<br>
It takes care of interpolation and synchronizing different data
streams as they are typical in robotic systems.<br>
<br>
I hope this solves all your questions, otherwise you are welcome
for further questions.<br>
<br>
Best,<br>
Matthias<br>
<br>
P.S. Moved this topic to rock-users...<br>
<br>
<br>
On 08.09.2015 20:02, <a class="moz-txt-link-abbreviated" href="mailto:Evangelos.Boukas@esa.int">Evangelos.Boukas@esa.int</a> wrote:<br>
</div>
<blockquote
cite="mid:27135_1441735362_55EF22C2_27135_831_1_OF91B08142.8351914F-ONC1257EBA.00573EC4-C1257EBA.00631ED2@esa.int"
type="cite"><font face="Verdana" size="2">Dear ROCK devs,</font>
<br>
<br>
<font face="Verdana" size="2">I am at ESTEC/ESA and we are using
ROCK
on our new robot named:"HDPR". We are close to the state that
we can go on the field to collect a dataset but, since I'm a
fairly new
user/dev, I have a question: </font>
<br>
<br>
<font face="Verdana" size="2">I am using a custom build stereo
camera,
with two firewire ptgrey connected on the same IEEE 1394 bus.
So, using
the inherent 1394 properties, the two cameras are synchronised.</font>
<br>
<font face="Verdana" size="2">Now, software-wise I am using in a
ruby
script the "</font><a moz-do-not-send="true"
href="http://rock-robotics.org/stable/pkg/drivers/orogen/camera_firewire/index.html"><font
face="Verdana" size="2" color="blue"><u>drivers/orogen/camera_firewire</u></font></a><font
face="Verdana" size="2">"
component twice for the each camera and then the "</font><a
moz-do-not-send="true"
href="http://rock-robotics.org/stable/pkg/perception/orogen/stereo/index.html"><font
face="Verdana" size="2" color="blue"><u>perception/orogen/stereo</u></font></a><font
face="Verdana" size="2">"
to produce the disparity like this:</font>
<br>
<br>
<font face="Verdana" size="2">Ptgrey_camera_1->camera_firewire_orogen-----|-->stereo_orogen->disparity</font>
<br>
<font face="Verdana" size="2">
|</font>
<br>
<font face="Verdana" size="2">Ptgrey_camera_2->camera_firewire_orogen-----|</font>
<br>
<br>
<font face="Verdana" size="2">A struct view of the cameras in the
rock-display
reveals that there is a timestamp from each camera like this:</font>
<br>
<font face="Verdana" size="2">Left PanCam:</font>
<br>
<font face="Verdana" size="2">Time: 28 Aug 2015 17:23:33.993947</font>
<br>
<font face="Verdana" size="2">Received time: 1 Jan 1970 01:00:00.0</font>
<br>
<font face="Verdana" size="2">Right PanCam:</font>
<br>
<font face="Verdana" size="2">Time: 28 Aug 2015 17:23:33.993943</font>
<br>
<font face="Verdana" size="2">Received time: 1 Jan 1970 01:00:00.0</font>
<br>
<br>
<font face="Verdana" size="2">I assume by now that "Time" means
sampled time and "Received time means" time saved to disk/ram!
Then we log the data in a .log file. In order to export the data
to useful
.png files I use the following commands:</font>
<br>
<font face="Verdana" size="2">$ rock-export hdpr_perception.0.log
--stream
/pancam_left.frame --filename "Pancam_#TIME_0.png"</font>
<br>
<font face="Verdana" size="2">$ rock-export hdpr_perception.0.log
--stream
/pancam_right.frame --filename "Pancam_#TIME_2.png"</font>
<br>
<br>
<font face="Verdana" size="2"><u>Question one:</u></font>
<br>
<font face="Verdana" size="2">Even thought the images are actually
synchronised
(I can see it from the product), the timestamps i am getting are
not the
same because of the aforementioned struct properties. Is there
an official
way of fixing this issue and have the images reported with
exactly the
same timestamp, or should I create another component (or alter
the stereo
one) in order to "fake" the timestamps to match? Something like
the</font><font size="3"> </font><a moz-do-not-send="true"
href="http://wiki.ros.org/message_filters#Time_Synchronizer"><font
size="3" color="blue">ROS
time synchronzer</font></a><font size="3"> would be perfect.</font>
<br>
<br>
<font face="Verdana" size="2"><u>Question two:</u></font>
<br>
<font face="Verdana" size="2">The fact is that we are using
several sensors
on the rover (2 Stereo, IMU, TOF, DGPS) and in the best case we
would like
to have them all synchronised (at some point since they've got
different
frequencies) or at least real-time like, i.e. to know exactly
when to expect
the images. Is there any "easy" (obviously, that is not easy)
way to do this in ROCK, since we cannot hardware trigger all of
the sensors?</font>
<br>
<br>
<font face="Verdana" size="2">Thank you for your help and your
time,</font>
<br>
<font face="Verdana" size="2">Evangelos Boukas</font>
<br>
<font face="Verdana" size="1" color="#2f2f2f">=========================================================================</font>
<br>
<br>
<font face="Verdana" size="1" color="#2f2f2f">Dip.Eng | M.Sc. in
E.E.|Computer
Vision & Robotics Researcher | European Space Agency NPI</font>
<br>
<font face="Verdana" size="1" color="#2f2f2f">Laboratory of
Robotics and
Automation | School of Engineering | Democritus University of
Thrace</font>
<br>
<font face="Verdana" size="1" color="#2f2f2f"><a class="moz-txt-link-abbreviated" href="mailto:evanbouk@pme.duth.gr">evanbouk@pme.duth.gr</a>
| </font><a moz-do-not-send="true"
href="http://robotics.pme.duth.gr/boukas"><font face="Verdana"
size="1" color="blue">http://robotics.pme.duth.gr</font></a><font
face="Verdana" size="1" color="#2f2f2f">
| </font><a moz-do-not-send="true"
href="http://robotics.pme.duth.gr/boukas"><font face="Verdana"
size="1" color="blue">http://robotics.pme.duth.gr/boukas</font></a><font
face="Verdana" size="1" color="#2f2f2f">
</font>
<br>
<br>
<font face="Verdana" size="1" color="#2f2f2f">ESA - European Space
Agency</font>
<br>
<font face="Verdana" size="1" color="#2f2f2f">TEC-MMA - Automation
and
Robotics Section </font>
<br>
<br>
<br>
<font face="Verdana" size="1" color="#2f2f2f">ESTEC - European
Space research
and TEchnology Centre</font>
<br>
<font face="Verdana" size="1" color="#2f2f2f">Keplerlaan 1, PO Box
299 </font>
<br>
<font face="Verdana" size="1" color="#2f2f2f">NL-2201 AZ
Noordwijk, The
Netherlands </font>
<br>
<font face="Verdana" size="1" color="#2f2f2f"><a class="moz-txt-link-abbreviated" href="mailto:Evangelos.Boukas@esa.int">Evangelos.Boukas@esa.int</a>
|
</font><a moz-do-not-send="true"
href="http://www.esa.int/TEC/Robotics/"><font face="Verdana"
size="1" color="blue">http://www.esa.int/TEC/Robotics/</font></a>
<br>
<font face="Verdana" size="1" color="#2f2f2f">Tel. +31 71 565
5499 </font>
<br>
<font face="Verdana" size="1" color="#2f2f2f">=========================================================================</font>
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</blockquote>
<br>
<br>
<pre class="moz-signature" cols="72">--
--
Matthias Goldhoorn
Unterwasserrobotik
Standort Bremen:
DFKI GmbH
Robotics Innovation Center
Robert-Hooke-Straße 5
28359 Bremen, Germany
Phone: +49 (0)421 218-64100
Fax: +49 (0)421 218-64150
E-Mail: <a class="moz-txt-link-abbreviated" href="mailto:robotik@dfki.de">robotik@dfki.de</a>
Weitere Informationen: <a class="moz-txt-link-freetext" href="http://www.dfki.de/robotik">http://www.dfki.de/robotik</a>
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