Build your rig

There's no specific guide to make your own rig.

I will show my own rig so you get an idea of what is needed.

Just respect those rules:

• Safety before anything. Think in yourself and in the others.
• Mount it safely on the car or where you are using it (motorcycle, bike). We don't want the rig flying and making damage to anyone.
• There should be no movement between cameras. The most important feature of the rig.
• Make it light and easy to transport, mount and remove from the car.
• Select good webcams, not expensive ones, but cameras easy to mount in the rig and with good image quality. Should be DirectShow compatible (PS3 Eye is not compatible with my software, you have to use third party software to capture with those cameras).
• Get cameras with the biggest horizontal FOV possible (>70º) but not fish eyes (<100º). Be careful, some measure FOV vertically, others horizontally and others in the diagonal.
• If possible select 16:9 cameras, you get an wider range horizontally.
• I used 60cm between cameras, you can use another measure, try and give feedback.

My rig:
Before continuing please take look a this list:

Cameras that work with the program:

• Logitech C920
• Logitech C625

Cameras with problems:

• Hercules HD Sunset (works at 640x480)

I used two Logitech C920 (the right one). They have good image, good lenses and they are fast.

But they are not really cheap. I also tried two Logitechs C625 and they are also good.

  

Normally I use 786x480 px resolution and I find it enough.

If you are able to synch at bigger resolutions, go for it, but expect gigantic point clouds.

Those cameras have a good format to mount on the rig. They are mounted upside down in an L aluminium section. This assures stability to the camera fixation.

If you already noticed, I added a rectangular section aluminium bar to avoid torsion of the L bar. When I mounted the cameras on the car the L bar was always flexing and torsioning giving errors on the calibration.

If you have bars for your car, just mount this rig on the bars but if you are like me and have no bars, just use a steady and safe solution to put the rig on the car.

I fixed the rig with two common stripes.

Request help to someone so while you drive he/she controls the laptop. We don't want problems with the police or accidents.

Here's a little gallery for inspiration:

   

 

Mounting position/direction

Well to get better reconstruction results, usually I point the cameras down filling most of the image (3/4) with the road surface, but your camera direction wont be the same as the camera dislocation.

In doubt, try to level the camera with the road. I have achieved good results with both solutions so just try.

Making the camera levelled with the road as the advantage that the reconstruction is levelled  in case your first reconstructed frame was taken on levelled road.

Other alternatives

Using DSLR cameras or other similar:

Could be a good solution to get huge resolutions.

Right now PVS uses SBS movies. Using this system you have to create the SBS movie from still photos or from the movies of the two cameras.

There's a problem synchronizing the cameras for video capture. Look at this possible solution at http://www.3dfilmfactory.com.

To create the SBS movie I recommend VirtualDub and/or AviSynth (and a good interface for AviSynth like AvsPmod).

You might need some codecs to deal with your files.

Using GoPro or other action cameras:

Same as above, with another problem, how to synchronize them? You can always use still images, but for movies they are not really good. Even the stereo GoPro as synchronization problems.

Some action cameras can be connected to the PC as a webcam. That might be a solution.

Also High FOV is hard to calibrate. The calibration module is not prepared to calibrate above 100º FOV.

Remember that you have to mount the cameras on a solid rig without movement between them and disable autofocus.

 Also making still photos takes much more time than a movie, but at least you have the guarantee that they are synchronized since you take them standing still.

Imagination (and money) is the limit: