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flip/mirror video image on signal

Q

Quack

Jan 1, 1970
0
Hi,

I am looking for a way (if possible and simple enough) to flip/mirror
the image of a PAL video signal prior to encoding it in an embedded
application.

PAL signal ->
PAL signal -> [video switch] - [?] signal output -> [encoder]
PAL signal ->

currently, without the [?] its running just fine, to switch video i
use Maxim 4545 video switch chips - i was wondering if there might be
some kind of chip to stick after that (so only a single signal) that
can flip/mirror the image ...

Otherwise i'll leave it up to the processor and do it in software
after encoding, but it would be nice to have it in the hardware in
this case.

Alex.
 
M

Michael A. Terrell

Jan 1, 1970
0
Quack said:
Hi,

I am looking for a way (if possible and simple enough) to flip/mirror
the image of a PAL video signal prior to encoding it in an embedded
application.

PAL signal ->
PAL signal -> [video switch] - [?] signal output -> [encoder]
PAL signal ->

currently, without the [?] its running just fine, to switch video i
use Maxim 4545 video switch chips - i was wondering if there might be
some kind of chip to stick after that (so only a single signal) that
can flip/mirror the image ...

Otherwise i'll leave it up to the processor and do it in software
after encoding, but it would be nice to have it in the hardware in
this case.

Alex.

You have to strip the sync from the video, invert the video, and add
the sync back to the inverted video.

--
We now return you to our normally scheduled programming.

Take a look at this little cutie! ;-)
http://home.earthlink.net/~mike.terrell/photos.html

Michael A. Terrell
Central Florida
 
Q

Quack

Jan 1, 1970
0
You have to strip the sync from the video, invert the video, and add
the sync back to the inverted video.

do you know of any single-chip solution to this or something very simple ?
that sounds a bit out of my league ..
 
I

Iwo Mergler

Jan 1, 1970
0
Quack said:
Hi,

I am looking for a way (if possible and simple enough) to flip/mirror
the image of a PAL video signal prior to encoding it in an embedded
application.

PAL signal ->
PAL signal -> [video switch] - [?] signal output -> [encoder]
PAL signal ->

currently, without the [?] its running just fine, to switch video i
use Maxim 4545 video switch chips - i was wondering if there might be
some kind of chip to stick after that (so only a single signal) that
can flip/mirror the image ...

Otherwise i'll leave it up to the processor and do it in software
after encoding, but it would be nice to have it in the hardware in
this case.

Alex.

Alex,

it's probably simpler to do this in software. The hardware
solution involves a digitiser, 1-2 lines worth of storage
(1-2 frames for flip) and a D/A converter.

While possible, I don't think anyone has done a single chip
for this. Check out chips/devices which have PIP (Picture in
Picture) capability, this has similar hardware requirements.

The traditional approach to flip/mirror the picture is
to swap the connections on the deflection coils in the
monitor.

Kind regards,

Iwo
 
T

Ted Wilson

Jan 1, 1970
0
[email protected] (Quack) wrote in message news: said:
Hi,

I am looking for a way (if possible and simple enough) to flip/mirror
the image of a PAL video signal prior to encoding it in an embedded
application.

PAL signal ->
PAL signal -> [video switch] - [?] signal output -> [encoder]
PAL signal ->

currently, without the [?] its running just fine, to switch video i
use Maxim 4545 video switch chips - i was wondering if there might be
some kind of chip to stick after that (so only a single signal) that
can flip/mirror the image ...

Otherwise i'll leave it up to the processor and do it in software
after encoding, but it would be nice to have it in the hardware in
this case.

Alex.

Hi Alex

If you want to mirror-image the picture, (i.e. transpose it left to
right about the vertical axis), then this is a far from trivial task.

Basically, you will have to strip off the video content, digitize and
buffer it, and then reconstitute a composite video signal with the
video content applied in reverse order - i.e. what was at the end of
the video line at the beginning and vice-versa.

If you want to flip the image, (as in picture upside down), then you
will again have to digitize and store the picture, this time requiring
a buffer large enough to store a complete frame, and then reconstitute
your video with the lines in reverse order.

I'm not aware of any proprietary chips to do this, but that's not to
say there aren't any out there somewhere.

Regards

Ted Wilson
 
W

Wade Hassler

Jan 1, 1970
0
[email protected] (Quack) wrote in message news: said:
Hi,

I am looking for a way (if possible and simple enough) to flip/mirror
the image of a PAL video signal prior to encoding it in an embedded
application.

PAL signal ->
PAL signal -> [video switch] - [?] signal output -> [encoder]
PAL signal ->

currently, without the [?] its running just fine, to switch video i
use Maxim 4545 video switch chips - i was wondering if there might be
some kind of chip to stick after that (so only a single signal) that
can flip/mirror the image ...

Otherwise i'll leave it up to the processor and do it in software
after encoding, but it would be nice to have it in the hardware in
this case.

Alex.

You could reverse the leads to the horizontal deflection yoke in the
viewing monitor.
Wade
 
W

Winfield Hill

Jan 1, 1970
0
Ted Wilson wrote...
Alex Quack wrote ...

If you want to mirror-image the picture, (i.e. transpose it left to
right about the vertical axis), then this is a far from trivial task.

Not necessarily of help to Alex, but he should be aware that
there are many inxepensive LCD video displays that have switch-
selectable built-in image-reversal. Useful, for example, in an
LCD rear-view mirror display. Surely there must also be some
affordable video cameras with switch-selectable image-reversal.
Certainly there are image-reversing sensors, especially BW ones
used in 3-CCD cameras, etc.

Google lists about 9,140,000 million hits for video camera, but
only 77 with "image-reversal."

Also, there are image-reversing lenses (having a prism I suppose).

Thanks,
- Win

whill_at_picovolt-dot-com
 
M

Marlboro

Jan 1, 1970
0
[email protected] (Quack) wrote in message news: said:
Hi,

I am looking for a way (if possible and simple enough) to flip/mirror
the image of a PAL video signal prior to encoding it in an embedded
application.

PAL signal ->
PAL signal -> [video switch] - [?] signal output -> [encoder]
PAL signal ->

currently, without the [?] its running just fine, to switch video i
use Maxim 4545 video switch chips - i was wondering if there might be
some kind of chip to stick after that (so only a single signal) that
can flip/mirror the image ...

Otherwise i'll leave it up to the processor and do it in software
after encoding, but it would be nice to have it in the hardware in
this case.

Alex.

Hi Alex

If you want to mirror-image the picture, (i.e. transpose it left to
right about the vertical axis), then this is a far from trivial task.

Basically, you will have to strip off the video content, digitize and
buffer it, and then reconstitute a composite video signal with the
video content applied in reverse order - i.e. what was at the end of
the video line at the beginning and vice-versa.

If you want to flip the image, (as in picture upside down), then you
will again have to digitize and store the picture, this time requiring
a buffer large enough to store a complete frame, and then reconstitute
your video with the lines in reverse order.

I'm not aware of any proprietary chips to do this, but that's not to
say there aren't any out there somewhere.

Regards

Ted Wilson

I did it in xilinx virtex with 2 frame buffers, actually it can
rotate any degree. The analog front end has sync striper, A2D,
Analog back end has D2A...Wonder if any chip can do that..
but it may be out there somewhere...(TI DSP maybe?)
 
B

Bob Stephens

Jan 1, 1970
0
Ted Wilson wrote...

Not necessarily of help to Alex, but he should be aware that
there are many inxepensive LCD video displays that have switch-
selectable built-in image-reversal. Useful, for example, in an
LCD rear-view mirror display. Surely there must also be some
affordable video cameras with switch-selectable image-reversal.
Certainly there are image-reversing sensors, especially BW ones
used in 3-CCD cameras, etc.

Google lists about 9,140,000 million hits for video camera, but
only 77 with "image-reversal."

Also, there are image-reversing lenses (having a prism I suppose).

Thanks,
- Win

whill_at_picovolt-dot-com

Seems like, as someone already suggested, that this would be much easier to
accomplish in soft/firmware - assuming the display is stored in RAM
somewhere.


Bob
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Winfield Hill
Also, there are image-reversing lenses (having a prism I suppose).

I don't understand how an ordinary triangular prism could do that. A
convex lens with a real object at the centre of curvature (twice the
focal distance) produces a real image that is inverted (both
'vertically' and 'horizontally'). I just did the experiment to make
sure.
 
D

Daniel Haude

Jan 1, 1970
0
On 16 Jan 2004 02:09:56 -0800,
in Msg. said:
If you want to mirror-image the picture, (i.e. transpose it left to
right about the vertical axis), then this is a far from trivial task.

....unless the signal comes from a tube camera or is only to be displayed
on a CRT. In these cases it's enough to swap the terminals of the H
deflection coils. I'm 99.9% sure that this won't help the OP any, but at
least it's a trivial solution for a related problem ;-)

--Daniel
 
Q

Quack

Jan 1, 1970
0
Thanks everyone for the suggestions!
I had hoped there was a single chip, but its not worth the effort to
design something that complex for this.

The viewing monitor/lcd etc can not be tailored to suit, neither can
the camera - for this project the 'box in the middle' must handle
everything. (the video output does not go to any display, it goes to
an embedded encoder to turn it into a digital video stream) - but
thats okay, the 'encoder' portion (check original post) is done in
software, and it wont be too difficult to add the mirror/flip in there
- the images are captured as a YUV byte stream, and can be altered in
any desirable way.

Thanks again,

Alex.
 
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