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Haku

3D Stereo imaging idea on the cheap

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After playing around with FPV driving my RC car and having a lot of fun I'd like to take it further in the future and do stereo imaging using two cameras to get a 3D picture, but the solutions I've seen are expensive and require the need of 3D LCD glasses or LCD shutter glasses, however I've figured out a way of getting a stereo image using conventional LCD glasses and any colour tv or LCD screen.

Putting the idea into practice however is a completely different matter.

Basically you use two cameras, black & white preferably, convert the signal from one camera into a red picture and the other into a green picture (cue penny dropping sound :)), merge the two into a single video stream and transmit it with a standard 1.2g or 2.4g AV transmitter.

edit: or two colour cameras, one with a red filter and one with a green filter over the lens, then simple merge the two signals into one and transmit.

On the viewing end you simply get some coloured filters, one red, one green and place them over the LCD glasses. For a normal colour tv or LCD screen just use red/green 3D glasses.

et. voila, cheap 3D which doesn't require expensive equipment to record or view, meaning anyone with some red/green colour filter glasses can view the image.

So, er, does anyone have any ideas where I might start on finding the necessary bits to change the colour of a video signal, and then merge two signals into one?

Edited by Haku

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Looking into this more I've discovered this particular type of 3D imaging (red/green or red/cyan etc) is called Anaglyph imaging, and there's a way of taking anaglyph pictures/video using a single camera, it's all done with mirrors ;)

You can make your own pretty cheap but it looks like such a solution won't be any good for radio controlled things (especially planes) due to the size of the device, unless you work out how to make it smaller:

http://www.instructables.com/id/EPTUHNQHR2...87AG7/?ALLSTEPS

A two-camera setup would be a lot preferable to a box attached to the front of the single video camera but I can't yet find any devices small enough for RC car/plane use that will merge the signal of two cameras. Searches for genlocks and video mixers turn up ones meant for desktop not portable use.

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I don't think you will find an off-the-shelf all-electronic solution anywhere. I guess you'll have to hire a skilled electonic engineer to design a circuit for you. The circuit would be rather complicated as in order to blend two images it will have to sync signals from two cameras, which is quite tricky. So a mechanical solution would really be the simplest and the cheapest. Like the one in the link. You just have to make it smaller

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A manufacturer I have contacts with has just sent a newsletter announcing pretty cheap 3D video glasses. The little detail is that it works with the field-sequential principle. That's a bit of a standard, which was made to be totally compatible with current video hardware, including DVD players and so on. The standard video signal is interlaced, and transmits the 2 fields (odd lines /even lines) one after the other. That 3D system is very simple, it sends each field to one of the screens. You obviously get half the resolution, but that has the great advantage of being usable with the current hardware as it doesn't have to know that both fields come from different sources.

That's a bit tricky to use with our application too, as we would need a circuit that extracts one field out of one camera's signal and the second from the other camera. As the cameras don't have their clocks synchronised a simple switching wouldn't work. That would be pretty complicated signal processing, as would the 2 B/W camera setup.

The best for us would either be the mechanical system if it can be made small enough, or the solution I usually recommend: Just take 2 full systems. 2 cameras, transmitters, receivers. To view, take 2 cheap sets of glasses, pick the controller in one to put it in the second one, wire each to one LCD instead of both. That's easy to do with the ones I have at hand.

Of course, the price is different then...

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Yeah to combine two un-sync'd cameras you need a genlock solution which can store a complete frame from one (or both) camera so the images can be merged. If it were possible to sync two cameras together then merging the two signals might be easy, well that is if you know your video electronics.

Field sequential is a fairly good solution but it requires special hardware to view the resulting footage, as well as cameras that are in-sync. During some extensive searching last night I found a couple of webpages where people had made their own circuits for turning two cameras into a single field sequential video image, with instructions and circuit diagrams:

http://stereo-video.home.att.net/

http://webpages.csus.edu/~heinega/Two_Came...cuit_Design.htm

The 2nd page doesn't seem to sync the cameras before combining the fields together so I wonder how it copes with the cameras not being in sync.

If someone were to develop a small device that merged two images together from two unmodified cameras so red/green anaglyph video can be transmitted back to the viewer, I wonder what sort of market there is out there for a cheap 3D solution that doesn't require special viewing hardware.

I'm thinking of doing one of those anaglyph adaptors with the mirrors but on a small scale for my RC car, the "eye" distance won't need to be very big because I'll be looking at objects only a few feet away using a small camera lens so the overall size should be quite small.

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The 2nd page syncs as well :

The video cameras I used for this project were a Sanyo VCC-3972 which is capable of  using external sync and a Sanyo VCC-6574A. One camera must be capable of using external sync, so that the scan lines of the two cameras are in sync.

Now about finding a good CCD board camera that has that sync input... :(

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