Missing Link

That is difficult. I do not think there is a steroscopic vision system (yet?), you may need a combination of senors such as sonic and vision.

I am understanding you right - is all that you require actually just a very basic CMM (coordinate measuring machine)

For example:

http://www.romer.com/

other systems:

http://www.metris.com/cmm_scanners/

If you wish to do 3D scanning, one of the cheapest is the David Laser scanner.

high resolution, and very affordable.. scalable too.

I saw a presentation.. right into solidworks with a 3d complex surface... it works.

check it out.

Can you adapt a pre-focus mechanism from a digital camera?

You may be able to use something like a focal point between two known lenses that can be controlled that could be read when they are in focus. To much trouble. Depth perception units available use a laser or sonic device that comes off the shelf and are already being used extensively for depth perception. You won't need to "invent" anything. It is a straight forward ready made solution.

Many years back Polaroid is to sell n ultrasonic range finding kit, which was the same mechanism used for autofocussing their cameras.

Various such devices are available in the market.

http://www.hobbyengineering.com/H2951.html

http://www.cs.sfu.ca/fas-info/cs/CC/821/li/material/source/Jarvis83.pdf

http://ddr.nal.usda.gov/dspace/bitstream/10113/2991/1/IND43946900.pdf

Depending upon the object you are trying to "see" and the distance between the reference point and the object, a time-of-flight distance sensor coupled with a PLC could be an option.

Here is a link to one of IDEC's time-of-flight distance sensors. This has an analog output that can be fed back into one of our PLCs. The PLC could then control the output based on the input it is receiving from the sensor.

Sensor Link - http://www.idec.com/usen/products/Catalogs/Sensors/S80/overview.html

PLC Link - http://www.idec.com/usen/products/Catalogs/PLCs/MicroSmartPentra/overview.html

Sincerely,

Britt Davis

This can be done with 'machine vision' technology. This can continuously scan product on a production line to provide 3D imagery of each item for quality and process control. A company that specializes in this technology is Dipix. A laser mounted at 45 degrees form vertical projects a line across the object and a camera mounted vertically scans the line.

I wonder if the knowledge of "classical physics" is something similar to a magic wand? It sounds like a biological problem with digestion and missing links. It almost sounds real.

Banner sells ultrasonic sensors with a an adjustable range (distance span) and linear outputs of 0-10 V and 4-20 mA.

Yahlasit

A simple electro/mechanical solution would be something like a tank level sensor. Use the variable voltage output as the input to your motor control.

The method used by astronomers might have some bearing here.. they profile the stars based on the spectral analysis to determine the type of star (and therefore standard diameter), and then they use a standard sizing chart to compare apparent diameter to similar diameter stars at known distances. (and especially our sun)

the basic idea is that objects decrease in visual size as the recede from the observer. If the object is an emitter of light, its intensity also decreases with the distance.

What you could do is have a point type light source, (cone shaped beam) shining from near the same origin as your camera. Then that spot on the distant object that it shines on can be identified by the camera software (by color frequency?), and measured for spot diameter and intensity (greyscale). the resulting data could compare to the object in question that the spot is on, for the relative size and distance data. Both the intensity and spot diameter will give you distance information.. (assuming clear air, common surfaces and textures, and perhaps compensation for other forms of interference)

If two such spots were projected at different angles (targeting different objects?) then the software could (knowing they are projected along two sides of a triangle, and perhaps you have an encoder on your projectors to make it easier to know the angle of separation) normalize the spot diameters and calculate all the other trigonometric data. (distance between objects themselves, as well as distance to objects, and all angles)

hope that makes sense..

http://en.wikipedia.org/wiki/Absolute_magnitude

http://en.wikipedia.org/wiki/Apparent_magnitude

just a thought.

Chris

now that I have drawn this up, I think it might be similar to the david laser scanner method.

Chris

There are number of laser distance measureing devices out there. never had use for one myself but they appear to do what you want.