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 Post subject: Stereo Vision using regular USB cameras
PostPosted: 25 Aug 2011, 19:36 

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25 Aug 2011, 19:29
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I am new to this group and technology, so my questions may be trivial:

I would like to have two identical USB cameras assembled together about 10cm apart and connected to my laptop each via its own USB cable. Is there any way I can combine the two streams into one single 3D video in real time ? I would like to view the movie on a regular laptop and use 3D glasses.

Thanks for the help


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 Post subject: Re: Stereo Vision using regular USB cameras
PostPosted: 25 Aug 2011, 20:22 
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There are multiple ways you can do that and you will need a few things depending on what you choose to use.

The easiest way is to use a stereoscopic 3D multiplexer that will allow you to control both web cameras simultaneously and record their output. I've pretty much explained most the process and requirements here: http://3dvision-blog.com/dual-camera-rig-live-stereoscopic-3d-preview-and-alignment-method/

Although in the article above I've used a more complex solution that relies on two cameras and capture cards, as a means of aligning a parallel stereoscopic 3D rig, but you can use the same method with webcams and it will be much easier to setup and instead of using the output of the two cameras for live display in 3D you will be recording it to a file in Side by Side format.

It is recommended to save it in a Side by Side format as this will allow you to view it not only on normal displays with a pair of anaglyph glasses, but also on different stereoscopic 3D display solutions. You can just vary the output you need using a stereoscopic player such as the Stereoscopic Player by the same author of the Stereoscopic Multiplexer mentioned in the article.

As for the 10 centimeter distance between the two webcams, you may want to consider lowering that depending on what you will be filming - smaller distance if something close or larger distance for something that is further away...

There are also some applications that are specially designed to allow you to capture 3D content using two webcams, but if you are going to spend some money on software as most of these are not free anyway, then you better give them for something more flexible than can be used not only with web cameras.

An alternative would be to just get a 3D webcamera that has the two lenses already fixed and software that will synchronize them, so you will only need to capture the output in the right 3D format. Such a 3D webcam is Minoru for example: http://3dvision-blog.com/minoru-the-worlds-first-consumer-3d-webcam/

The drawback of a solution such as Minoru 3D webcam is that you have the two lenses fixed at a preset distance, so you are not able to vary the interaxial in order to get better results depending on what you are shooting, you need to move the camera closer and due to the relatively low distance you are not able to shoot very distant objects with depth.

And there are even more options, but please do share a bit more details about what you will be shooting, so that everyone here could be of a batter assistance and help you with the most appropriate solution for your case...


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 Post subject: Re: Stereo Vision using regular USB cameras
PostPosted: 25 Aug 2011, 20:54 

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I would like to thank you for the reply. This will be an excellent start to get into 3D/Stereo. My project involves two cameras which I modified to enable them to be most sensitive in the near IR range. In this wavelength range one can see a few milliliters underneath the skin (blood vessels). My goal now is first to be able to get a real time 3D view of whatever I can see under the skin. Once this is done, I will probably invest some money and get two high quality cameras so that I increase the resolution and clarity. Next, I will want to get into the display side and see if I can render the output, perhaps overlay the images with some nice graphics. This will also be, yet, another new field for me to get into.

I do expect many challenges as I make progress.
Regards


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 Post subject: Re: Stereo Vision using regular USB cameras
PostPosted: 25 Aug 2011, 21:14 
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That sounds like a serious challenge to me, but I'd be glad to help as much as I can.

I'm not sure how thing will look when captured in 3D format, as essentially the infrared footage will be black and white and that is something prone to having more ghosting/crosstalk and it might not look best when viewed with anaglyph glasses, although having B&W footage may be better for anaglyph than having it in color due to the use of color filters.

Also I suppose you will be shooting up close and small parts of the blood vessels at a time, which would mean that both webcamera should be close to each other. Or if you try to shoot the whole body of a person at a time you will need them further apart, although 10 centimeters might still be too much of a separation.

Also when you have some trouble or questions feel free to ask, also we'd be glass if you share some of your results as well, so that other users that have similar ideas in mind may also benefit from the information available... ;)


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 Post subject: Re: Stereo Vision using regular USB cameras
PostPosted: 25 Aug 2011, 22:59 

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Thank you,

I will definitely share my results. I use this project because I am interested in learning the stereo/3D concept and I also have great interest in 3D rendering and augmented reality. I just needed to find a project which will keep me focused.

BTW, there is no special reason why I selected 10cm between the cameras, I am simply stuck with the cameras I have today. In fact, I want to look at a very small region on the body, say about 40mm x 40mm from a very short distance, just as if one would use a magnifying glass. When I get to it, I will need cameras and the correct lenses (by then I will learn to calculate focal lens and other parameters). At this point I do not even what to ask.

Regards


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 Post subject: Re: Stereo Vision using regular USB cameras
PostPosted: 13 Feb 2013, 16:59 

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What about hardware synchronization? How will stereoscopic multiplexer deal with genlocking?


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