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In lugnet.robotics, Dave Baum writes:
> I hope people don't get too worked up about all of this. I assume TLC
> decided to put links on their site, then someone had the idea that if
> they used an associate link, they'd get a little extra income. From
> their perspective, why not take advantage of a little free money?
That's certainly their choice. I just hope they realize it's sending a mixed
message. If you don't know how to recognize an Amazon.com associate ID when
you see one, it looks as though TLC is finally (yay) supporting these two
wonderful books, when in fact the opposite is true.
> [...]
> Is it just the fact that they are profitting from AFOL contributions
> that is upsetting? [...]
IMHO, TLC is misleading people into believing that they support the books --
which they might FAIK, who knows -- but there's clearly mixed signals. If
they weren't receiving a kickback, then it would be clear that they
unconditionaly supported the books.
I'm happy to TLC support of AFOLs, but this still leaves me nervous and
skeptical. :)
> Is there a concern that the lego links will reduce the hits through
> similar links on other AFOL sites?
I'd feel the same uncomfortable feeling even if there weren't the same types
of links on any non-TLC sites.
> Although I can see where this would
> be disconcerting, its hardly a reason to get upset with Lego.
I'm not sure 'upset' is the right word. Disappointed and uncomfortable are
closer to the right word. LEGO is sending the wrong message to people who
stop by.
--Todd
> Its just free market operating with respect to referrals. If other sites
> (LUGNET, etc) were depending on such money, then we will need to find
> other ways to support them.
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In lugnet.robotics, Todd Lehman writes:
> > Although I can see where this would
> > be disconcerting, its hardly a reason to get upset with Lego.
>
> I'm not sure 'upset' is the right word. Disappointed and uncomfortable are
> closer to the right word. LEGO is sending the wrong message to people who
> stop by.
(The above is from April.)
I just stumbled across this at the official LEGO Mindstorms website...
http://lego4.legomindstorms.com/webx?14@119.40wPawM8ax6^33@.ee6e227/2
It's worth adding a link to it just for posterity since it refers to
specific articles on this thread by their URLs.
Anyway, I'm not sure who "little horn" is, but he speaks with the
defensiveness of someone who works for LEGO. I don't get the impression
that he "gets it" (i.e., why the coat-tailing sends the wrong message).
http://www.legomindstorms.com/home/books/index.asp
I can't help but notice the notice at the bottom of that page --
"...These links are provided for your convenience only..."
What they really mean is something else, but the double-meaning is humorous.
:)
Oh well. At least they're linking to the books, which helps support the
community.
--Todd
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Subject:
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Stereo Vision
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Newsgroups:
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lugnet.robotics
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Date:
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Thu, 10 Aug 2000 10:05:13 GMT
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Original-From:
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Laurentino Martins <lmartins@marktest.{nomorespam}pt>
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Hi
As you may know my current project has everything to do with image recognition.
I was reading one tread in this newsgroup and suddenly it struck me that many of the problems I currently have in finding the contours of the objects can be overcome it I have stereo vision!
Then I figured that the only way to do that with just one camera was if I can place a set of mirrors in the front to the camera and split vertically the image in two, each set of mirrors giving an image a few centimeters apart.
Then all I have to do is to compare the left and the right parts of the images and find the differences between them.
Any thoughts about that?
Laurentino Martins
[ mailto:lau@netcabo.pt ]
[ http://www.terravista.pt/Enseada/2808/ ]
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Subject:
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Re: Stereo Vision
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Newsgroups:
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lugnet.robotics
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Date:
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Thu, 10 Aug 2000 11:30:56 GMT
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Original-From:
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Marco C. <marco@soporcel.[antispam]pt>
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Yup :)
I thought of, *after dealing with the mono vision*, going for a stereo
approach, because this is one way of dealing with distance measuring, or at
least, better object evaluation/recognition.
At first I thought of using two USB cams, but then, after thinking about
the technical problems dealing with two video sources, I thought of that
solution exactly. Using a kind of technic common to professional binocullars:
Left Right
: :
\:..\**/..:/
*\ :\/: /* 4 Mirrors
: :
|: :|
Camera
Well... in theory this works, but, in practice, I was expecting
difficulties when setting the angles of the mirrors correctly.
If more motor outputs were available, one could control the outside
mirrors, to deflect or inflect (just like we do with the eyes)
With angle-sensors attached, one could even do a crude distance measuring,
when trying to focus an individual object/point of reference.
Anyway, without the pair of motor/angle-sensor attached, it's still
possible to do crude distance measuring with the fixed angle.
Like this, we get better edge/object recognition
Oh well... when I have the time... but, anyway :) Laurentino, keep us up to
date with your project :)
At 11:05 10-08-2000 +0100, you wrote:
> Hi
> As you may know my current project has everything to do with image • recognition.
> I was reading one tread in this newsgroup and suddenly it struck me that
many of the problems I currently have in finding the contours of the
objects can be overcome it I have stereo vision!
> Then I figured that the only way to do that with just one camera was if I
can place a set of mirrors in the front to the camera and split vertically
the image in two, each set of mirrors giving an image a few centimeters apart.
> Then all I have to do is to compare the left and the right parts of the • images and find the differences between them.
> Any thoughts about that?
> Laurentino Martins
____________________
Marco C. aka McViper
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Subject:
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Re: Stereo Vision
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Newsgroups:
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lugnet.robotics
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Date:
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Thu, 10 Aug 2000 12:36:29 GMT
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Original-From:
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Marco C. <marco@*antispam*soporcel.pt>
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At 13:45 10-08-2000 +0200, you wrote:
> > If more motor outputs were available, one could control...
> LOL! I wonder when LEGO actually will put in more I/O in the RCX :)
> Keep up the good thinking and have a nice day!
I'm planning to add a RCX to my CyberMaster, hopefully, this Xmas.
I've done tests with MotorOutput->SensorInput direct connection and it
works, using the Off() and Float() commands to simulate the On/Off state.
Using a simple comms rotine, similar to the VLL code available already in
legOS and NQC source code, or similar to bar-code reader code, one can
devise a bidirectional serial comm with the CyberMaster<->RCX.
Advantages ? PC RF-comms and/or IR-comms with 4 sensors and 4 or even 5
outputs (a pair of each assigned to the comms, so only 4 from the 6 available)
I could save a RCX output, I dunno, by connecting like this:
CyberMaster_Input_1 <= Bumper1...
CyberMaster_Input_2 <= Bumper2...
CyberMaster_Output_A => LeftMoveMotor
CyberMaster_Output_B => RightMoveMotor (or something like that)
CyberMaster_Output_C =>-\
CyberMaster_Input_3 <=--|
RCX_Input_1 <=>---------/
RCX_Input_2 <= LeftEyeAngleSensor
RCX_Input_3 <= RightEyeAngleSensor
RCX_Output_A => LeftEyeAngleMotor
RCX_Output_B => RightEyeAngleMotor
RCX_Output_C => UpDownEyeAngleMotor
So, it's possible to have one pBrick do all the walking, and the other
pBrick obey cmds to move the "eyes" and even, with the possible 3rd output,
control the up/down movement of the eyes.
Or if considered a luxury the Independent Eye movement, the RCX would do
the "arm" controlling instead. ...or both, with a 2nd RCX, because the 1st
could pass along CyberMaster comands through IR messages to any other
possible RCX's we might want to add.
$$$ :)
____________________
Marco C. aka McViper
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Subject:
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Re: Stereo Vision
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 11 Aug 2000 10:04:42 GMT
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Original-From:
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Laurentino Martins <lmartins@marktestAVOIDSPAM.pt>
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1551 times
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This approach has several problems.
One is that the left image will show you smaller objects than the right, because the light travels a greater distance.
The second is that precision is very important and the mirrors must be fixed otherwise will make the image tremble a lot.
If you want to subtract two almost identical images to see the edges like I want to, one pixel of unalignment is too much.
Sorry the english
At 00:38 11-08-2000 Friday, Doug Weathers wrote:
> You might be able to save yourself some trouble with mirrors if you mount
> the camera to one side instead of in the middle.
>
> . .
> \ . \ .
> \....\ .
> \ . \ .
> . .
> ##### <-- camera lens
Laurentino Martins
[ mailto:lau@netcabo.pt ]
[ http://www.terravista.pt/Enseada/2808/ ]
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Check this out ;)
Recognizing Three-Dimensional Objects by Comparing Two-Dimensional Images.
Daniel P. Huttenlocher, Liana M. Lorigo. IEEE Conference on Computer Vision
and Pattern Recognition. June 1996, San Francisco, CA, USA
http://www.ai.mit.edu/people/liana/cvpr-2col.ps.gz
____________________
Marco C. aka McViper
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