Passive Optical Range Finder

[noble24]

I'm building an augmented reality training system (similar to the virtual yellow first-down marker in football). In order to precisely generate realistic virtual graphics I need to know the distance between the camera and the real object for every pixel in the camera's field of view. I am looking for something that can calculate distances in this matter for ranges between 100m to 4000m. I have looked into stereo vision which could solve the problem but adds its own rather large footprint and problems to the system (tightly calibrated cameras along a large baseline). Any suggestions or creative ideas/solutions would be helpful.

My best guess for a solution came after playing around with our camera I noticed that focus was a potential way to determine distance (although difficult at such long ranges). Unfortunately I know next to nothing about optics and also wanted to know if there was a way to determine distance to each pixel not with a long baseline, but with a long focal length?

 

[IRstuff]

It would be too slow and probably well less than accurate. You probably would be unable to determine position any better than about 100 ft at max range. It would also probably be absurdly slow, unless you plan on using an image processing software to perform the focus.

A more practical, but expensive, solution might be to get a laser rangefinder such as the Riegl LPM-2K, which is accurate to 2 inches up to 2500m. If you scan your area from the side, you can cover the entire 4000m depth to a width of over 2000.

http://www.rieglusa.com/new-site/lpm_ptm/e_lpm-2k.htm

At the other end of the cost spectrum is the Leica Disto laser rangefinders, which all run under $800, but they're limited to about 200m range, with no scanning capability:

http://www.disto.com/scripts/wgate/...&~http_use_compression=&~http_compress_level=

TTFN

 

[noble24]

Perhaps I wasn't as clear as I should have been. It needs to be a passive scanner. No emmisions (ultrasonic, laser, radio, etc.). I realize that I am asking an exceptionally difficult question, but this is how innovation occurs. My idea is based on the fact that through a single lens everything has a focus point that indicates distance. So the challenge is to find a way to accurately measure distance using focus points. If it is inaccurate and takes a long time to scan, then it's inaccurate and takes a long time to scan. These things can be improved once you have a concept. You have to crawl before you walk. So the question is how do you make it work?

 

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