Superimposed video crosshairs

[Andrew Chin]

Does anyone know a circuit which could generate crosshairs which can
be superimposed over an existing video feed such as from a CCD camera?

I'd like to make some simple crosshair patterns like a horiz+vert
line, horiz line, vert line, frame, corners, etc. A microcontroller
of somesort could generate the patterns but I'm not sure how to
overlay the crosshairs without disrupting the original video feed.

 

[Mike Harding]

On 27 Oct 2003 23:24:03 -0800, chinsta00@hotmail.com (Andrew Chin)
wrote:

Does anyone know a circuit which could generate crosshairs which can
be superimposed over an existing video feed such as from a CCD camera?

I'd like to make some simple crosshair patterns like a horiz+vert
line, horiz line, vert line, frame, corners, etc. A microcontroller
of somesort could generate the patterns but I'm not sure how to
overlay the crosshairs without disrupting the original video feed.

Did exactly that (and rather more) somewhere over 20 years
ago Used an NEC video controller with some dynamic ram
and wrote the digital data to that then synced and mixed it
with the incoming video, The circuits and software are long
gone though I'm afraid. Surely a net search for "video overlay"
will turn up lots of clues?

Mike Harding

 

[David L. Jones]

chinsta00@hotmail.com (Andrew Chin) wrote in message news:<dea6e0ed.0310272324.4eb6a22b@posting.google.com>...

Does anyone know a circuit which could generate crosshairs which can
be superimposed over an existing video feed such as from a CCD camera?

I'd like to make some simple crosshair patterns like a horiz+vert
line, horiz line, vert line, frame, corners, etc. A microcontroller
of somesort could generate the patterns but I'm not sure how to
overlay the crosshairs without disrupting the original video feed.

You could use the (nearly obsolete but still available) STV5730A OSD
chip. You can program custom characters to create various lines or
whatever. A two chip solution with say a PIC micro tied onto it.
Alternatively you can use one of the various modules around that have
this chip on it already and are easy to program with the serial port.
Dontronics have (or used to have) a SimStick version available.

Regards
Dave

 

[Don McKenzie]

"David L. Jones" wrote:

chinsta00@hotmail.com (Andrew Chin) wrote in message news:<dea6e0ed.0310272324.4eb6a22b@posting.google.com>...
Does anyone know a circuit which could generate crosshairs which can
be superimposed over an existing video feed such as from a CCD camera?

I'd like to make some simple crosshair patterns like a horiz+vert
line, horiz line, vert line, frame, corners, etc. A microcontroller
of somesort could generate the patterns but I'm not sure how to
overlay the crosshairs without disrupting the original video feed.

You could use the (nearly obsolete but still available) STV5730A OSD
chip. You can program custom characters to create various lines or
whatever. A two chip solution with say a PIC micro tied onto it.
Alternatively you can use one of the various modules around that have
this chip on it already and are easy to program with the serial port.
Dontronics have (or used to have) a SimStick version available.

Regards
Dave

still have Dave,
http://www.dontronics.com/dt108.html
may be of some help.
Don...

--
Don McKenzie E-mail: http://www.dontronics.com/e-mail.html
Home Page: http://www.dontronics.com

USB to RS232 Converter that works http://www.dontronics.com/usb_232.html
The World's Largest Range of Atmel/AVR & PICmicro Hardware and Software

 

[KoRRupT]

"Andrew Chin" <chinsta00@hotmail.com> wrote in message
news:dea6e0ed.0310272324.4eb6a22b@posting.google.com...

Does anyone know a circuit which could generate crosshairs which can
be superimposed over an existing video feed such as from a CCD camera?

I'd like to make some simple crosshair patterns like a horiz+vert
line, horiz line, vert line, frame, corners, etc. A microcontroller
of somesort could generate the patterns but I'm not sure how to
overlay the crosshairs without disrupting the original video feed.

I'm looking for more or less the same, for a small project too.

I just recently found this...

http://www.decadenet.com/bob3/bob3.html

haven't used it but it looks like it'll do what you want.

It has various 'line characters' in it's extended RAM character sets

let us know what you end up doing.

 

[David L. Jones]

On Thu, 30 Oct 2003 13:44:15 +1030, "KoRRupT" <me@nowhere> wrote:

"Andrew Chin" <chinsta00@hotmail.com> wrote in message
news:dea6e0ed.0310272324.4eb6a22b@posting.google.com...
Does anyone know a circuit which could generate crosshairs which can
be superimposed over an existing video feed such as from a CCD camera?

I'd like to make some simple crosshair patterns like a horiz+vert
line, horiz line, vert line, frame, corners, etc. A microcontroller
of somesort could generate the patterns but I'm not sure how to
overlay the crosshairs without disrupting the original video feed.

I'm looking for more or less the same, for a small project too.

I just recently found this...

http://www.decadenet.com/bob3/bob3.html

haven't used it but it looks like it'll do what you want.

It has various 'line characters' in it's extended RAM character sets

let us know what you end up doing.

I'd love to know what OSD chip they are using...
Looks as though they have rubbed off the numbers on the chip.
They may have gone with a custom chip in this third generation device,
to prevent problems with the discontinuation of almost all the OSD
chips out there.

Dave
---------------------------
(remove the "_" from my email address to reply)

 

[KoRRupT]

"David L. Jones" <tronnort_@yahoo.com> wrote in message
news:3fa0e0b1.1940350@News.CIS.DFN.DE...

to prevent problems with the discontinuation of almost all the OSD
chips out there.

i wonder why they're all discontinued... one would have thought OSD IC's are
pretty useful/popular thing with electronics hobbyist.

 

[Rod Speed]

KoRRupT <me@nowhere> wrote in message
news:3fa1bd50$1@duster.adelaide.on.net...

David L. Jones <tronnort_@yahoo.com> wrote

to prevent problems with the discontinuation
of almost all the OSD chips out there.

i wonder why they're all discontinued... one would have thought
OSD IC's are pretty useful/popular thing with electronics hobbyist.

Presumably there arent enough of those to provide a viable market.

 

[John Tserkezis]

Rod Speed wrote:

i wonder why they're all discontinued... one would have thought
OSD IC's are pretty useful/popular thing with electronics hobbyist.

Presumably there arent enough of those to provide a viable market.

This was brought up on another group, my theory was that since the bulk of
modern video equipment out there generates the video digitally, OSD text is
generated using the processors that are already there.
The separate OSD devices have effectively become obselete because it's easier
to create the text at the same time as the video, rather than do it later in
the analogue realm.

The fact that hobbyists have lost out because of this is "just too bad".
Besides, couldn't a pic and a sync separator do it? Albeit with a few limitations?
--
Linux Registered User # 302622 <http://counter.li.org>

 

[Rod Speed]

John Tserkezis <jt@techniciansyndrome.org.invalid> wrote in message
news:3fa2de8b$0$21650$afc38c87@news.optusnet.com.au...

Rod Speed wrote:

i wonder why they're all discontinued... one would have thought
OSD IC's are pretty useful/popular thing with electronics hobbyist.

Presumably there arent enough of those to provide a viable market.

This was brought up on another group, my theory was that since the
bulk of modern video equipment out there generates the video digitally,
OSD text is generated using the processors that are already there.

The separate OSD devices have effectively become obselete
because it's easier to create the text at the same time as the
video, rather than do it later in the analogue realm.

Yep, thats another way of spelling out the lack of a viable market now.

The fact that hobbyists have lost out because of this is "just too bad".

Yep, and if there was a viable market, presumably someone
could just buy up whats still around and flog them to that market.

Besides, couldn't a pic and a sync separator do it? Albeit with a few limitations?

Yeah, that was my reaction. Havent actually tried it tho.