Re: Re: Re: 3rd ave sensor design

From: Jack Greenbaum (jackg@cache.crc.ricoh.com-DeleteThis)
Date: Thu Sep 29 1994 - 15:40:57 PDT 

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From: jackg@cache.crc.ricoh.com-DeleteThis (Jack Greenbaum)
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In-Reply-To: <9409292207.AA13889@hpmsd3.sj.hp.com-DeleteThis> (message from Kirk Lindstrom on Thu, 29 Sep 1994 15:07:38 -0700)
Subject: Re: Re: Re: 3rd ave sensor design
Reply-To: jackg@crc.ricoh.com-DeleteThis date:thu, 29 Sep 1994 15:07:38 -0700 Errors-To: listserv_err@jr.hpl.hp.com-DeleteThis Reply-To: wind_talk@opus.hpl.hp.com-DeleteThis Originator: wind_talk@opus.hpl.hp.com-DeleteThis Sender: wind_talk@opus.hpl.hp.com-DeleteThis Precedence: bulk From: Kirk Lindstrom <kirk@hpmsd3.sj.hp.com-DeleteThis> X-Listprocessor-Version: 6.0c -- ListProcessor by Anastasios Kotsikonas X-Comment:  Windsurfing Discussion Mailing List

   KenP writes:
> The point is that even a defocused low-power laser is much brighter from
> a mile away (the distance at 3rd) than a white sunlit card. To get a
> good signal from a sunlit card, you need to view *only* on the part that
> gets obscured by the spinning cups. Otherwise, the background
> contributes such a high ambient light that you cannot get your signal
> out.

The entire target would spin, like those signs you see in front of
stores. What the detector would see is the difference between front and
back (white and black) of the spinner, not the difference between
spinner and background. Depending on the sensor (and post processing)
the target would not need to fill the field of view.

> (Hitting a six inch target at one mile means aiming to better
> than .01 degree. This sounds hard/expensive.)

Could be. However it is an entirely passive approach.

-- Jack

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