kim@amdahl.UUCP (Kim DeVaughn) (09/16/86)
[ ... go ahead, eat my bits ... ]
Recently, I purchased a Digi-View for my Amiga, and am now looking
for some kind of "box" that I can best describe as an "NTSC video
color filter". I'm wondering if anyone on the net knows of such a
device.
For those of you who don't follow net.micro.amiga, the Digi-View is
a video digitizer that takes a standard 1 volt p-p NTSC signal as
it's input, and with the s/w provided, produces a data file of that
image that can be displayed, printed, etc. by the Amiga.
Normally, the NTSC signal is produced by a B&W TV camera. For
color digitization, three seperate images are digitized thru red,
green, and blue filters, and then combined by the s/w to produce
a full color picture (320x200 pixels, 4096 colors). The results are
really impressive ... especially considering the Digi-View is less
than $200 (without the camera).
What I would also like to do, is digitize images from my VCR (I have a
Cannon VR-HF600A, which has a "rock-solid" freeze-frame). As is, this
works well in producing monochrome images (from either a B&W or color
source), but needs a "color filter box" between the VCR and the Digi-View
for color results.
Conceptually, this box would have red, green, and blue "color-killer"
switches on it so one could filter out two of the three colors at a
time. The output of the box could be either the actual "red image"
(or green or blue), or the B&W representation of the same ... either
should work just fine based on my experiments.
Anyone have any ideas on where to find such an animal, or how one might
go about building one (I'm a h/w person, but know next to nothing about
video)?
I have looked at several of the "special effects" video processors that
are available. Lots of nifty and interesting things can be done with
these, but so far, none do the kind of thing I've described above. Any
help would be greatly appreciated.
Replies should probably be directed to net.micro.amiga where this
discussion really belongs, or of course you can email me, and I'll
summarize to the net.
Thanks alot!
/kim
--
UUCP: {sun,decwrl,hplabs,ihnp4}!amdahl!kim
DDD: 408-746-8462
USPS: Amdahl Corp. M/S 249, 1250 E. Arques Av, Sunnyvale, CA 94086
CIS: 76535,25
[ Any thoughts or opinions which may or may not have been expressed ]
[ herein are my own. They are not necessarily those of my employer. ]grr@cbmvax.cbm.UUCP (George Robbins) (09/18/86)
In article <3702@amdahl.UUCP> kim@amdahl.UUCP (Kim DeVaughn) writes: >[ ... go ahead, eat my bits ... ] > >Recently, I purchased a Digi-View for my Amiga, and am now looking >for some kind of "box" that I can best describe as an "NTSC video >color filter". I'm wondering if anyone on the net knows of such a >device. > >What I would also like to do, is digitize images from my VCR (I have a >Cannon VR-HF600A, which has a "rock-solid" freeze-frame). As is, this >works well in producing monochrome images (from either a B&W or color >source), but needs a "color filter box" between the VCR and the Digi-View >for color results. > >Conceptually, this box would have red, green, and blue "color-killer" >switches on it so one could filter out two of the three colors at a >time. The output of the box could be either the actual "red image" >(or green or blue), or the B&W representation of the same ... either >should work just fine based on my experiments. > >/kim UUCP: {sun,decwrl,hplabs,ihnp4}!amdahl!kim It looks like there is a pretty good chance that the Amiga Genlock peripheral would be able to do this, with a little jury rigging. One of the things the genlock will do is to convert the external NTSC video sources into a analog RGB signal. You would have to rig up a switch to select the output, perhaps have to combine the selected RGB signal with composite sync, and have to have some kind of monitor coming off of the Amiga composite video or tapped in between the Genlock and the Amiga so that you could effectivly control the Digiview program. This is *NOT* a statement that such a configuration will work, just some discussion about the possibilities. Also, the elusive Genlock is still scheduled for release sometime around the end of the year... -- George Robbins - now working for, uucp: {ihnp4|seismo|caip}!cbmvax!grr but no way officially representing arpa: cbmvax!grr@seismo.css.GOV Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)
dave@onfcanim.UUCP (Dave Martindale) (09/18/86)
I've left net.video and net.graphics in the list of newsgroups this reply goes to, since this is of potential interest to people there. In article <3702@amdahl.UUCP> kim@amdahl.UUCP (Kim DeVaughn) writes: > >For those of you who don't follow net.micro.amiga, the Digi-View is >a video digitizer that takes a standard 1 volt p-p NTSC signal as >it's input... > >Normally, the NTSC signal is produced by a B&W TV camera... > >What I would also like to do, is digitize images from my VCR (I have a >Cannon VR-HF600A, which has a "rock-solid" freeze-frame). As is, this >works well in producing monochrome images (from either a B&W or color >source), but needs a "color filter box" between the VCR and the Digi-View >for color results. > >Conceptually, this box would have red, green, and blue "color-killer" >switches on it so one could filter out two of the three colors at a >time. The output of the box could be either the actual "red image" >(or green or blue), or the B&W representation of the same ... either >should work just fine based on my experiments. Unfortunately, the colour NTSC signal has none of the colours directly present in it. It is a black&white TV signal with two channels of "colour difference" information superimposed on it via a high-frequency carrier. In order to extract the individual colours, you have to decode the NTSC encoding the same way that a television set does. This involves a crystal oscillator locked to the colourburst in the signal, two synchronous detectors, and then a matrix of resistors to convert the Y (luminance), R-Y, and B-Y signals obtained back into R, G, and B. At that point you have three B&W signals just as they would have come from a colour camera, perhaps with sync still added. I know Tektronix makes an NTSC decoder such as this, but it's laboratory quality and costs thousands of dollars. What you want is basically the colour processing stages of a TV set. You could build it yourself, using the same chips the TV manufacturers use, or just figure out how to extract the signal you want from an old TV. Once you have the three signals, just use relays or FET switches to select the one of the three that you want. Your digitizer may lock onto the signal as it is, or you may have to put sync pulses back into it to make it look like a real B&W signal. By the way, the output really should be just a B&W image, not a single-colour colour image. The latter will still have the high-frequency colour carrier present in it, which will likely show up as noise in the digitized signal unless the digitizer is careful to filter it out.
kish@caip.RUTGERS.EDU (Bill Kish) (09/18/86)
Does anyone have experience with capturing SUN 3/160 graphics on film, VHS, or Beta ? Does anyone have suggestions on who sells RGB to NTSC encoders and/or a piece of hardware that will perform "scan conversion" whereby 1/2 of the detail of the 1152 pixel line can be captured ? -Bill Kish