I don't think there would be a sensible way of hashing the video data,
but if you had an external one-frame delay, you could probably do
something pretty useful by looking at the sum of the differences
between current and delayed data on a byte-by-byte basis. This would
greatly simplify the buffer RAM addressing - you'd only need a counter
and a pretty simple read-old/write-new  scheme. In addition to the RAM
for the frame delay, you'd probably need an FPGA,  but not a
particularly big one. You might just be able to get the PIC to handle
some or all of the summing and masking, and some of the control &
timing though.=20

On Tue, 11 Jun 2002 12:51:35 -0400, you wrote:

>Hi All,
>I have watched many topics through this list, and
>I'm often amazed at what people are doing with PIC's.
>
>I have wondered more than once if a PIC could be
>used for video signal motion detection. I assume
>that a sync separator and NTSC(or PAL) to RGB conversion
>would be handled by dedicated chips, but could
>a PIC go from the resulting RGB signals to
>some kind of motion detector output?
>
>I understand that this is most often done in
>PC's by keeping a copy of the previous video frame,
>and comparing it to the current frame. Blanking
>of certain areas and an overall sensitivity
>adjustment are also useful. Obviously, a bare
>PIC could not buffer a full video frame. It is
>also unlikely that you could resolve all the
>information in a current frame at the full speed
>of the incoming signal.
>
>Some method of mathematically "hashing" the video
>as it streams into the PIC, even if only every
>2nd, 3rd, or 4th pixel is sampled, might provide=20
>enough info for the program to detect change.
>
>Of course, a certain amount of background noise
>may be present, even on a "dark" signal, so some
>sensitivity adjustment will be needed.
>
>This is all just wild ideas at the moment. Has
>anyone else ever considered something like this?
>
>Thanks,
>Lyle Hazelwood

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads