Subject:
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Re: A Generic Idea
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Newsgroups:
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lugnet.robotics
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Date:
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Sun, 5 Jan 2003 14:40:09 GMT
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Viewed:
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722 times
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In lugnet.robotics, Steve Baker <sjbaker1@airmail.net> writes:
> I suppose you could buy an NTSC TV tuner/video-grabber card for your PC
> and grab the image that way.
>
> I'm told that the quality is pretty awful - and that you need really good
> lighting to see anything much...but that's hearsay - I havn't seen one of
> these myself.
Well, to find outline of objects you'd need a low-res (easy to simplify and
automatically filters out irrelevant details), color (to avoid two objects
of the same material getting their outlines fused together by the image
processing software). A 64x64 image that is automatically reduced to 256
colors (by a filter like in Photoshop) would be perfect! That would take 4KB
per image, uncompressed. With simple RLE compression probably much less than
half that.
The problem is finding a camera that does that BEFORE transmitting the
picture. The only equipment that is reasonably cheap that does this is the
cel phones I was talking about. Another way to do it would be to append a
small microcontroller gadget to the camera. Either way it means hacking
someone's image format, but at least with the cel phones the compression is
already done, and the other end, which has a fast CPU, has all the time in
the world decompressing it.
> > So all we can conlude with todays equipment is that you need more CPU power
> > to handle the data from a camera?
No, we either need more bandwidth from camera to CPU or reduce the bandwidth
load before it comes to the CPU. A fast CPU is what you need to
capture/interpret the images.
Hmm I think we're straying from the topic. The generic idea was to provide a
constant link between robot and a better brain. And the celphone (which is
prolific in Europe, every teenager has one, and 1/3 of the grown-ups have
one ;)) seemed to be the most generic of the links. It also seemed simple
and cheap to use, as compared with a PDA+camera which may run you $500-$800.
In Sweden, a phonecall and $1 can give you a cel phone, provided you
subscribe to a certain operator for 24-48 months of course. (Those sneaky
so-and-so :P) This may not be the case in every country of course.
Whatever the "better brain" is, we need a decent speed interface from it to
an RCX. The PDA+USB tower (on the robot) suddenly looks more and more
attractive, especially if you could tweak BrickOS or sth to make it faster
(I'm assuming the RCX's IO chips is the bottleneck).
But I haven't opened the RCX, maybe there's a port which can be used for
direct serial, (parallel) or USB cable transfer ? Has anyone built a cable
data interface PC<->RCX?
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Message has 1 Reply:
 | | Re: A Generic Idea
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| (...) Yeah - but the amount of CPU horsepower to do that (on the robot remember) is comparable to the horsepower you'd need to extract the edges and do some simple image recognition. So why transmit the image at all? (...) Yes - but they don't (...) (21 years ago, 5-Jan-03, to lugnet.robotics)
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Message is in Reply To:
| | Re: A Generic Idea
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| (...) The problem is that the 27MHz frequencies are fairly tightly restricted in some countries. Here in the US, it's pretty much open-season, it's used by CB radios, radio controlled models - and various toys. However, in other countries (the UK (...) (21 years ago, 5-Jan-03, to lugnet.robotics)
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