Author Topic: Assistance on interfacing modules for video capture and processing it  (Read 1026 times)

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Offline cspinnerTopic starter

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Hi all, I am new to this forum as well as the world of robots. After reading the forums for the past few days, I feel myself gaining more interest and at the same time feeling a little daunted by the complexity in setting up a robot.

Summary of my project: I am required to do up a camera system for an UAV capable of tracking a fixed target on the ground. The UAV will circle round at the top of the target and my camera system will require to keep the target in view at all times (preferably at the centre of the screen). Autonomous too.

I am not so concern about the programming as of yet though I know that will be pretty tough. My first step is to acquire the necessary parts to get myself started. Limited budget too. approx. 300USD.

Questions:
1) If I am to use CMUCAM, am I able to capture the frames and transmit back to my laptop (mac) 500metres away to
process the image before sending a compensation message back to the servos to adjust the camera?

2) Can I use a normal camera for FPV (first person view) RC flying and send the video back to the laptop for processing? Or do I have to use a specialised camera such as cmucam?

Sorry if the questions are too confusing as I am still grappling with the terms and jargons.

Please advise and clarify if the intent is not clear.

Thanks.

yk

Offline SmAsH

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Re: Assistance on interfacing modules for video capture and processing it
« Reply #1 on: September 02, 2010, 02:33:46 PM »
You could just use a regular wireless camera to send frames to the pc and then a microcontroller at the pc end with wireless to interface with another microcontroller onboard the uav with the servos?
Howdy

Offline cspinnerTopic starter

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Re: Assistance on interfacing modules for video capture and processing it
« Reply #2 on: September 02, 2010, 06:30:08 PM »
Thanks Smash. To clarify, it is possible to use a 1/3 inch sony CCD camera used for FPV and transmit it back via an AV transmitter like this (http://www.bevrc.com/bev-13g-800mw-p-52.html?zenid=a92b1bef9f0080df7846a6ef147c17bf) to be received by the computer for image processing? And another set of wireless to communicate with the servos on board? Any way to share the wireless module among the parts via different channels? As the transmitter as mentioned is a AV transmitter, will i require a program to convert it from analog video to digital frames?

Oh ya, one more thing. If I have an auto pilot(ardupilot) on board, is there any way I can utilise that to help me in my target tracking?

Apologies if I make any technical boo boo here as I am confused with how the system works.

Thanks a lot once again.

Offline SmAsH

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Re: Assistance on interfacing modules for video capture and processing it
« Reply #3 on: September 03, 2010, 01:10:44 AM »
i cant see a problem with doing that as long as the camera you use has the correct outputs.
Another wireless is probably suggested as it can get complicated unless you can find a dual channel transmitter/reciever combo?
Also, with different wireless units they both only have to be one way.

With the convertions for the pc to record, you might be able to find a cheap pc capture card from an online store like dealextreme or ebay.

As for the third question, if you have spare pins and space on the mcu for the code, it could be done, but a smaller seperate microcontroller like an
attiny/atmega might be better suited to performing the task on its own.
Howdy

Offline dunk

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Re: Assistance on interfacing modules for video capture and processing it
« Reply #4 on: September 03, 2010, 01:43:47 AM »
transmitting video RF signals and data RF signals require completely different techniques.

video requires low latency, very high bandwidth and relatively low accuracy. (it doesn't matter if the occasional pixel is corrupted.)
data transmissions on the other hand need high accuracy and medium to low latency and bandwidth.

as a result you will not find an off the shelf RF solution for transmitting data and video on the same link.
try searching the internet for people wanting to transmit video using xbee modules to read about the issues involved. (i think there are 1 or 2 threads on this forum about similar.)

i'm not saying it is impossible, just more complicated than it sounds.

the simplest solution is to use a separate RF link for video and data.
make sure you run each link on completely different wavelengths (not just different channels).
read up on FPV systems for more information on running video transmitters right next to sensitive data receivers.


as for doing the video processing on-board,
this is possible but the technical challenges are far larger. the processing power involved in processing video is huge and coming up with a working system within the $300 budget may not be possible.
the additional problem of going this route is it is far harder to debug the system when all your processing is being done in mid air...


dunk.

 


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