Range finding and imaging using laser!!

Yes, but that CCD camera uses a custom sensor which enables very precise
control of the timing and measurement of the time of arrival at each CCD
pixel. Without this, as has been discussed before, the intensity would
also affect the image. However, the intensity contribution could be subtracted
out by first taking a reference frame that doesn't depend on distance.

In order for this to be implemented with a normal CCD camera, either direct
control of the electronic shutter is needed, bypassing any synchronous logic,
or a "sync" output from the camera must be available. Also note that the
charge integration times involved - 10s or 100s of ns - are several orders of
magnitude smaller than those normally used on all but very specialized CCD
cameras, even with a fast shutter. So, sensitivity is going to be very low.
A high power pulsed laser may be needed to generate adequate photons and even
then, the CCD may not be able to supply enough charge.

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A few google searches provided some hints that the shuttering is done
electronically. Some CCDs appear to be clockable at 10s of Mhz, is that fast
enough? There's a camera that appears to use this technique here
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The device I saw was working at maximum distances of about 20 feet.
Martin

In a TV studio meaning a few 10s of feet at most? The electronic shutter
would have to be consistent to a few ns - can they do that reliably on a CCD?

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I saw an interesting rangefinder type device using a CCD camera last year.
The target was illuminated with a brief pulse from an array of IR diodes.
The CCD was shuttered so that the shutter closed at the end of the pulse.
For reflections from near objects most of the reflected pulse was recorded
on the CCD. For distant objects, less of the reflected pulse reached the CCD
before the shutter closed. So, the CCD recorded brightness levels that were
related to distance. However, the brightness would also depend on the
reflectivity at IR of the object being targeted. If that's a constant, you
have a neat measure of distance. It's a simple way of getting a depth view
of a whole scene in one hit, without too much complex electronics. I'm not
sure how the shutter worked, I think it was electronic.

The rangefinder was being used in a TV studio virtual environment to measure
the distance of the presenter from the main camera, so they could walk
behind virtual objects in the studio - and it was working well. Maybe
clothes / skin have a constant reflectivity at IR?

Martin

Sure, if you know the size of the target, then you can figure the range
from the size on the CCD. :) Seriously, no, you can't get adequate timing
information from the CCD image to time of flight.

What sort of electronics experience do you have? A TOF rangefinder is a
non-trivial project.

For a 100 foot range, you're talking about 200 ns round trip. A pulse with
a few ns rise time needs to be generated and detected. To resolve
1 foot, you need a 500 MHz to 1 GHz counter. This isn't something you can just
put together if you're experience level is the Radio Shack 100-in-1 projects
kit. ;)

So, perhaps some more details of what you want to do and what you have done
would help.

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