rajeev karothia wrote:
Respected sir
I am working on telos mote and i have to interface webcam with
telos.....but i don't have proper Module and Component to do
this...can anyone know how can i capture and send Image via telos mote?
thanking you
Rajeev
Since I have seen no one respond to this, I'll toss my hat in the ring.
Rajeev, you do know, I hope, that at best the Telos can only transmit
250Kbps. This is, of course, raw transmission which does not include
the message overhead which can easily exceed 50% of the message packet;
so, your raw data transmission capability drops to about 125Kbps.
Again, this does not include the packets that are used in a network for
discovery, routing, etc., which cannot be estimated here. Lastly, the
Telos uses a single frequency band (2400-2483 MHz) which lends little
flexibility to respond to interference.
A typical webcam today has a minimal resolution of 320x240x24. If you
plan on transmitting a raw frame without compression or
"monochromization," the best transmission rate you will have is
(320x240x24)/125Kbps or 4 fpm (frames per minute). There are two
well-documented kinds of compression that you can use to reduce the
load: image compression (something like JPEG) and sending only the
changed sections of the image (I don't know the term, but it can be
found in MPEG1 through MPEG4). The problem with each of these is the
CPU: they are rather CPU-intensive algorithms. Can the Telos keep up
with that? I would guess "no".
While this is an interesting experiment, for anything useful I would
consider a different combination of components.
-Sean Walton
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