Re: ATM Something Usefull?

["Ken Hunter" <kb7h@onemain.com>]

Most likely you are looking at a Moire (sp?) pattern set up
by the pixel lines not matching between the LCD display
and your CCD camera. To check for this, rotate and tilt
the camera while looking for the patterns. If it is interference 
in the LCD display it won't change... if Moire, it will change
depending on the relationship of the two devices.

Ken Hunter


----- Original Message ----- 
From: "James Lerch" <jlerch1@tampabay.rr.com>
To: "ATM List" <ATM@shore.net>
Cc: <atm_free@yahoogroups.com>
Sent: Thursday, December 12, 2002 5:45 PM
Subject: ATM Something Usefull?


> 
> Greetings All,
> 
> I observed an interesting phenomenon today.  I was tasked with inspecting
> and imaging a set of damaged LCD monitors.  So I started to take some images
> with a Sony DSC-F707 digital camera.
> 
> The interesting bit was the Auto-Focus would snap into place and I would see
> incredible interference fringes.  If I moved the camera an inch
> Closer/Further away while locking the focus, the interference fringes would
> disappear.  Here's an example.
> 
> http://lerch.no-ip.com/atm/waves.jpg (118KB)
> 
> Obviously I was imaging the interference patterns between the two plates
> that sandwich the LCD crystals.  I just found it interesting (and maybe
> useful) that the fringes showed so well considering they were invisible to
> the naked eye or a slightly defocused camera.
> 
> Maybe this might be an idea for someone fringe testing some optics to try.
> 
> For what its worth, :)
> James Lerch
> http://lerch.no-ip.com/atm
> 
> 
>