Path: utzoo!mnetor!uunet!husc6!bloom-beacon!gatech!udel!burdvax!sdcrdcf!trwrb!cadovax!keithd
From: keithd@cadovax.UUCP (Keith Doyle)
Newsgroups: comp.sys.amiga
Subject: Re: Video Products
Message-ID: <2038@cadovax.UUCP>
Date: 12 Apr 88 18:15:42 GMT
References: <4834@sdcsvax.UCSD.EDU> <8379@agate.BERKELEY.EDU>
Reply-To: keithd@cadovax.UUCP (Keith Doyle)
Organization: Contel Business Systems, Torrance, CA
Lines: 75
Keywords: desktop video reviews perfect vision

In article <8379@agate.BERKELEY.EDU> doug@eris.UUCP (Doug Merritt) writes:
>There will necessarily be a loss in *potential* maximum quality
>when using an NTSC color camera instead of a black and white w/ color
>wheel, because NTSC has very limited color bandwidth. I wouldn't
>know how close Perfect Vision comes to the optimum with the color
>wheel approach.

Hard to say.  I agree that the BW of NTSC is a stumbling block and
this holds true with videotape sources as well as from color cameras.
And while I find PerfectVision useful, I would not give up my DigiView
for still art.  I find them each useful, according to what they're 
best at.  DigiView for still art, PerfectVision for multi-frame capture
from videotape.

>They have two versions, one for the 1000, and one for 500 and 2000.

Don't ask me what the difference is, the one I have has a standard
centronics parallel connector on the back.  I've used it on both
a 1000 and 2000.

>They claim to grab a one bit plane image in 1/60 of a second, and
>imply N/60 seconds for color, where N is the number of bitplanes.

I believe it's an entire grayscale (4 bits) image in 1/60th a second,
with 3 shots to get RGB.  Since it takes a couple of seconds to upload
the image from the box, color grab must be done from a still image, while
B&W is realtime.

>I haven't used it nor seen it in operation; I'm curious as to the
>quality...it sort of sounds like the best of DigiView and LIVE!
>wrapped up in one neat package.

I see that it addresses a need, to get decent frames from videotape.
I don't see it replacing my DigiView, just fitting in in a slot where
DigiView didn't perform.

>BTW although a lot of work went into DigiView 2.0, and it produces much
>better quality images than 1.0 (or than LIVE!, of course), I am still
>quite disappointed in the lack of flexibility in fine tuning the results.
>They very obviously did not have an image processing expert work with
>them on this. To get really high quality results depends far more on
>how well you pick the subject matter, and how carefully you adjust
>lighting conditions, than it does on any software adjustments.

I think that's a fact of life.  Lighting is EXTREMELY important
and something image processing only becomes a band-aid for.

>Too bad...you can do a lot with 21 bits/pixel of image information.
>If you bother. Which they didn't. Other than relatively straightforward
>dithering, which is necessary but not sufficient.

Sounds like you haven't figured out how to use it yet.  I thought it
was quite flexible in tuning the results.  Two things that help to
know are:

	1.  When you want to pump up the brightness/contrast, move the
	    brightness and contrast sliders up TOGETHER.  If you just turn
	    up the contrast, you lose a little brightness.  I've found
	    it most effective to tune the two pretty much together.

	2.  If you're working with color, try turning the saturation 
	    WAY DOWN.  I use it around -15, and don't lose much color,
	    it just tones down the predominate color.  If you have an
	    image with too much red (or blue etc.), DON'T just turn
	    down the red, the image will just turn green.  Leave the
	    red alone and back the saturation way off.

>All of which is to say that, if the Perfect Vision folks wanted to
>outdo DigiView, it would be relatively easy.

They both have their place, I wouldn't want to do without either of them
right now.

Keith Doyle
#  {ucbvax,decvax}!trwrb!cadovax!keithd  Contel Business Systems 213-323-8170