Subject:
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Vision Command capabilities revised
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Newsgroups:
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lugnet.robotics.vc
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Date:
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Tue, 7 Nov 2000 17:31:40 GMT
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Viewed:
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4339 times
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The Vision Command set has been on shelves for two months already. Did it meet
general expectations?
My opinion is that the Lego company did a pioneering work when introduced a
computer cam as a children toy. Maybe it was not so revolutionary step as
introducing the RCX but, at least, there is a cam that fits to other LEGO
bricks and there is a software that allows children (and not only children) to
learn and play with such advanced technologies like visual pattern recognition.
That's the good side and for a toy it is enough to meet children and their
parents' expectations.
AFOLs may have other opinion. We know now that the VC cam is actually a common
webcam wearing just a different coat and the software is rather limited, mainly
towards robotic applications. Well, this is the right time and right challenge
to break the constraints of the Vision Command.
Rainer Balzerowski in his post of 26.09. showed how the VC software can be
cheated to allow both VC based vision recognition and traditional RCX control.
It is one possible way. However it is still limited. For example, the VC
software cannot receive messages from outside (namely from the RCX) and also
the VC software is too "heavy" to fit to some applications.
It was Rainer again (post of Nov.2) who pointed to another possibility. He
proved that the VC cam is logitech-standard compatible and so the Logitech SDK
available at
> http://developer.logitech.com/sdk/
can be used for independent software development.
I tried the above SDK and it really works without any problems. The SDK is well
documented and includes programming examples for both Visual Basic and C++. The
Logitech Vportal2.dll has even a built-in motion detection event notification.
The Logitech SDK - namely its VB version - could be a nice platform for
developing advanced RCX+cam applications (also for Win2000 where LEGO software
fails!), because the LEGO's RCX control, the Spirit.OCX, is also a VB oriented
tool. In a single Visual Basic code one could be able to control the RCX
(directly or by sending messages to previously stored programs) and at the same
time to have full access to data comming from the cam. (They are directly
available in VBasic, though the Logitech says this is not suppported). I've
already tried some VBasic experiments with processing data from the cam, though
not in real time, yet. (I know that if VB is slow for some applications, later
I can rewrite the time critical code in C and make a DLL).
But there seems to be a serious problem. The Logitech Vportal2.dll (BTW it is
used also in the LEGO VC software) cannot work in parallel with the Spirit.Ocx.
Whenever I place both the controls in a single VB program, the program cannot
be executed because of some strange interaction between the two controls.
Messages like, OLE Automation error or Class definition error ocurr. I tried it
on two computers, on both I failed.
So my recently adopted solution is somewhat crazy. I have to run two VB
programs in parallel. One represents the main application and controls also the
cam (take snaps and processes them) while the other is something like a RCX
remote control (employing the Spirit.ocx). The latter serves as a dispatcher of
messages that are exchanged between the application program and the RCX.
My solution is not ideal and I hope it is just temporary, before a more
clever idea is born. But at least I can forget the LEGO software and go my own
way to play well.
So, this is my experience with learning robotics and vision recognition using
LEGO toys. (It is just a hobby, of course, but not so far from my main
profesional focus, which is speech recognition. If interested, see
http://itakura.kes.vslib.cz/kes/kes_lab.html).
Jan
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Message has 1 Reply:
 | | Re: Vision Command capabilities revised
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| (...) Just to throw another resource into the mix if anyone is unaware of this: Intel Open Source Computer Vision Library (URL) library is mainly aimed at real time computer vision. Some example areas would be Human-Computer Interaction (HCI); (...) (24 years ago, 30-Nov-00, to lugnet.robotics.vc)
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Message is in Reply To:
| | Re: Lego Cam API/SDK?
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| (...) Hi Lee As far as i know is there no available API, but as the lego cam seems to be a logitech quickcam you should try the logitech SDK at (URL) tried it and it does work. Rainer (24 years ago, 1-Nov-00, to lugnet.robotics.vc)
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