🚀 go-pugleaf

>I have a video camera, if I purchase the Video Blaster (?) board,
>which can capture the video image, is it as good an image as a scanner?

In some ways it is as good as a scanner or better, in others it falls
far short. A scanner is much higher resolution normally. A typical
grab of a video frame is 640x480 pixels. Unles the original is an object
2 inches wide or less, the scanner (typically 300 dots per inch) is
higher resolution. As well, there is considerably more noise in a video signal
than there is in a scanned image. The dynamic range of a scanner is usually
better. I think video is normally about equivalent to 16 bit colour where
the scanner can usually do 24 bit colour. And last but not least (at least
of the points that leap to my mind!), because of the way colour is handled
in NTSC video I think there are many colours that NTSC cannot handle
properly that can be done in printed matter, as well, there are certain
colours that can be adjacent to eachother in print that NTSC will bleed
together badly in video.

That said, there are certain times for screen use of images that the 
frame grabber approach is certainly the most economical, quickest and
most practical solution.

tj

bui@berlioz.nsc.com (Cuong Bui) writes:

>I have a video camera, if I purchase the Video Blaster (?) board,
>which can capture the video image, is it as good an image as a scanner?
>At least, it's a cheap and easy, not having to develop or blowup
>a picture for scanning, and huge source of data from video tape, TV ...
>Any pointer is appreciated.

Hi there

On my PC at home I have a Video Blaster (no camera) and a handy scanner,
and at our Computer Vision institute I frequently work with a video camera
that's connected to a frame grabber in a Sparc station. So I feel I can
comment a bit.

First, a home video camera outputs a composite signal whose colour resolution
is far below what a true colour scanner delivers (no RGB). The limitation here
is the television standard, but also home cameras are not as good as ones
used for broadcast. But that might not be important if colour is not of
interest.

The camera/frame grabber setup used at the uni is very high quality (RGB
camera, not composite) and we tried to "scan" maps and drawings with it.
It works, but the resolution of the output image is limited to the size
of a video image which isn't too great. Even my cheapo handy scanner produces
higher resolution.

The advantage of the camera setup is the possibility to make images of real
scenes, not just photos or paper drawings.

So if quality is important and all you want to do is scan from paper,
I think a flatbed scanner is the better option.

If you want to have a fun and cheap way to make images of whatever you like,
get the VB. The VB definitely IS fun :).


Greetings

Wolfgang

--
* Wolfgang Schwanke * Technische Universitaet Berlin * Germany * wolfi on irc *
* email: wolfi@cs.tu-berlin.de       *      wolfaefg@w250zrz.zrz.tu-berlin.de *

   Everybody needs a little love sometime; stop hacking and fall in love!

In article <1993Jan12.023100.14838@berlioz.nsc.com>
bui@berlioz.nsc.com (Cuong Bui) writes:
 
>I have a video camera, if I purchase the Video Blaster (?) board,
>which can capture the video image, is it as good an image as a scanner?
>At least, it's a cheap and easy, not having to develop or blowup
>a picture for scanning, and huge source of data from video tape, TV ...
>Any pointer is appreciated.
>
 
I have a Computer Eyes/Pro board that I connected to a VHS camcorder.
It works pretty well as a STILL image digitizer, but taking pictures of
anything moving more than a rock will produce a blurred image. But
I did manage to get a few nice images of my keyboard (what I wanted),
only having to play with the lighting and focus on the camera.
 
Hope this helps.