From:	Mongoose <m0ng005e@*********.COM>
Subject:	Re: Ultrasound vision
Date:	Thu, 4 Feb 1999 15:58:00 -0600

:> > Still, I do assume that SR's computers are powerful enough to need
only
:> > short integration times.
:>
:> No, no, integration time is not a function of computers. It's
a
:> measure of how many independent samples it takes to form a coherent
image.
:> It's a function of wavelength. The longer the wavelength, the more
:> samples you need the more time it takes to illuminate the target. We
can
:> do the math in realtime with computers now, but physics is hard to get
:> around.
:>
:Marc, I'm only going to say this much...
:
:It is a matter of both.
:
:-K

Not eventually. Better processing will get you closer to the
theoretical "best image",
but there is a limit.
The situation with EM imaging is analogous. Film has
very high integration speed, but with few photons (high speed film), the
image will ALWAYS be grainy. Similarly, with low frequencies (as in radio
telescopes), you need a longer "exposure" to get a decent image.
Its a basic fact of information theory that conveying information (in
this case the picture) requires a certain amount of energy exchange (in
photography, the photons- in Sonar, the sound picked up). With low
frequencies, you simply WILL need more time to gather the same quality and
quantity of info.

Mongoose