Re: [PSUBS-MAILIST] Blue-green laser (was: Empress of Ireland)

["Andy Jensen" <drewacard@charter.net>]

I have been thinking about this for a few months.  the 
scanning laser can be built with off the shelf components
i was thinking about using 2 rotating mirrors 2 CCD color 
camera and a blue laser diode the 2 cameras would be 
stationary a known distance apart and the laser scanner 
assembly would be located in between them.
     Camera     laser-scanner    Camera  

The scanner would have the first mirror spinning at high 
speed for horizontal scanning the second mirror the 
vertical scanner would spin at a speed so that the first 
mirror can make a full scan before the second mirror can 
make a small advance this would give a raster effect like 
a TV. using timing based off sync off the laser a computer 
or even a small micro-controller could calculate the 
distance from the CCD to the laser mark on the ground the 
major problem is that the scanning is based on the  CCD 
camera speed. 
the second camera is for the second half of the scan
and if wanted the 2 images could be overlaid a making the 
math a lot simpler.  A black and white camera could be 
used with a color filter to only pick up the laser light

I would also worry about the range and keeping the power 
of the laser low as not to blind the local inhabitances.

sorry about the long windiness 

Andy Jensen

On Fri, 21 Mar 2003 16:55:06 -0800
  Tim Reilly <TimR@cclengineering.com> wrote:
>I think the range is the key, because high-freq active 
>sonar will give you a
>decent view but not very far, and a blue-green laser 
>would sharpen up the
>image and has a little longer range, then combine it with 
>passive sonar
>which, if in a sound channel could be heard from Hawaii 
>to California.  So
>combining all of those in puts and number crunching in a 
>computer, I would
>think would give some good data.  How practical and cheap 
>it would be, at
>this point is anybody's guess.  If it could be made from 
>off the shelf
>technology all the better.
>
>Tim R.
>
>-----Original Message-----
>From: Coalbunny [mailto:coalbunny@vcn.com]
>Sent: Friday, March 21, 2003 4:37 PM
>To: personal_submersibles@psubs.org
>Subject: Re: [PSUBS-MAILIST] Blue-green laser (was: 
>Empress of Ireland)
>
>
>Depends on how far ahead of the sub you can get readings. 
> If you can
>get a projection at least 50' to which ever side you have 
>the transducer
>on, keep it stored in computer memory and you should be 
>able to project
>your course on there.  Or am I in the left field again?
>Carl
>
>
>
>-- 
>"You delight not in a city's seven or seventy wonders, 
>but in an answer
>it gives to a question of yours, or the question it asks 
>you, forcing
>you to answer, like Thebes through the mouth of the 
>Sphinx." -- Kublai
>Khan