OT: Backup camera glare

[bitrex]

The Chevy Volt's backup camera is ok under normal lighting conditions,
but at night if someone is parked behind me and has LED or HID
headlights on, there's so much lens flare/glare/CCD overdrive/whatever
that you can't see a blessed thing and it becomes nearly unusable.

Any suggestions for an expedient fix or a good aftermarket camera where
this is less of a problem, if not possible?

[TTman]

Tinted rear window ???

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

[bitrex]

Nah, the camera is mounted in a little housing above the license plate
frame.

[Jim Thompson]

Get a real car >:-}

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| STV, Queen Creek, AZ 85142 Skype: skypeanalog | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I'm looking for work... see my website.

Thinking outside the box...producing elegant & economic solutions.

[bitrex]

On 08/12/2017 03:12 PM, Jim Thompson wrote:
> On Sat, 12 Aug 2017 09:37:14 -0400, bitrex
> <bit...@de.lete.earthlink.net> wrote:
>
>> The Chevy Volt's backup camera is ok under normal lighting conditions,
>> but at night if someone is parked behind me and has LED or HID
>> headlights on, there's so much lens flare/glare/CCD overdrive/whatever
>> that you can't see a blessed thing and it becomes nearly unusable.
>>
>> Any suggestions for an expedient fix or a good aftermarket camera where
>> this is less of a problem, if not possible?
>
> Get a real car >:-}
>
> ...Jim Thompson
>

Sorry, my garage won't fit one of those aircraft carriers that someone
stuck wheels on.

[Martin Riddle]

On Sat, 12 Aug 2017 12:12:48 -0700, Jim Thompson
<To-Email-Use-Th...@On-My-Web-Site.com> wrote:

>On Sat, 12 Aug 2017 09:37:14 -0400, bitrex
><bit...@de.lete.earthlink.net> wrote:
>
>>The Chevy Volt's backup camera is ok under normal lighting conditions,
>>but at night if someone is parked behind me and has LED or HID
>>headlights on, there's so much lens flare/glare/CCD overdrive/whatever
>>that you can't see a blessed thing and it becomes nearly unusable.
>>
>>Any suggestions for an expedient fix or a good aftermarket camera where
>>this is less of a problem, if not possible?
>
>Get a real car >:-}
>
> ...Jim Thompson

Exactly, seems these euro style cars have one big blind spot.

Plus swiveling the neck is good exercise.

Cheers

[Carl Ijames]

"bitrex" wrote in message news:woIjB.190349$z73.1...@fx22.iad...

=======================================================

Piece of tint over the camera lens? Go to one of those places that tints
car windows and ask for some little scraps to play with.

--
Regards,
Carl Ijames

[Michael A. Terrell]

Jim Thompson wrote:
> On Sat, 12 Aug 2017 09:37:14 -0400, bitrex
> <bit...@de.lete.earthlink.net> wrote:
>
>> The Chevy Volt's backup camera is ok under normal lighting conditions,
>> but at night if someone is parked behind me and has LED or HID
>> headlights on, there's so much lens flare/glare/CCD overdrive/whatever
>> that you can't see a blessed thing and it becomes nearly unusable.
>>
>> Any suggestions for an expedient fix or a good aftermarket camera where
>> this is less of a problem, if not possible?
>
> Get a real car >:-}

They would have to take away Biterex's Y chromosome.


--
Never piss off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)

[Michael A. Terrell]

Not man enough to drive one? I'm looking at buying a 20' box truck,
and I've only driven pickup trucks, for over 25 years.

[bitrex]

On 08/12/2017 06:02 PM, Michael A. Terrell wrote:
> bitrex wrote:
>> On 08/12/2017 03:12 PM, Jim Thompson wrote:
>>> On Sat, 12 Aug 2017 09:37:14 -0400, bitrex
>>> <bit...@de.lete.earthlink.net> wrote:
>>>
>>>> The Chevy Volt's backup camera is ok under normal lighting conditions,
>>>> but at night if someone is parked behind me and has LED or HID
>>>> headlights on, there's so much lens flare/glare/CCD overdrive/whatever
>>>> that you can't see a blessed thing and it becomes nearly unusable.
>>>>
>>>> Any suggestions for an expedient fix or a good aftermarket camera where
>>>> this is less of a problem, if not possible?
>>>
>>> Get a real car >:-}
>>>
>>> ...Jim Thompson
>>>
>>
>> Sorry, my garage won't fit one of those aircraft carriers that someone
>> stuck wheels on.
>
>
> Not man enough to drive one? I'm looking at buying a 20' box truck,
> and I've only driven pickup trucks, for over 25 years.
>

That's fascinating

[k...@notreal.com]

The problem is the dynamic range of the camera isn't enough. Your
solution is rather like gluing sunglasses to your eyeballs. It's
going to decrease brightness in daylight and increase noise at night.

[k...@notreal.com]

On Sat, 12 Aug 2017 18:00:05 -0400, "Michael A. Terrell"
<mike.t...@earthlink.net> wrote:

>Jim Thompson wrote:
>> On Sat, 12 Aug 2017 09:37:14 -0400, bitrex
>> <bit...@de.lete.earthlink.net> wrote:
>>
>>> The Chevy Volt's backup camera is ok under normal lighting conditions,
>>> but at night if someone is parked behind me and has LED or HID
>>> headlights on, there's so much lens flare/glare/CCD overdrive/whatever
>>> that you can't see a blessed thing and it becomes nearly unusable.
>>>
>>> Any suggestions for an expedient fix or a good aftermarket camera where
>>> this is less of a problem, if not possible?
>>
>> Get a real car >:-}
>
>
>
> They would have to take away Biterex's Y chromosome.

There is none to take away.

[whit3rd]

On Saturday, August 12, 2017 at 6:37:25 AM UTC-7, bitrex wrote:
> The Chevy Volt's backup camera is ok under normal lighting conditions,
> but at night if someone is parked behind me and has LED or HID

> headlights on, there's so much lens flare/glare/...

There's a possibility of mounting two or three cameras instead of one
(they're available for $10 or so each), and fitting some with neutral density filters
so they accept bright conditions. Cleaning the lenses will help, too.

But, realistically, if you were standing a few feet from someone's headlights,
it's hard to see details like their fenders against the glare...

[Michael A. Terrell]

Just the photos in his purse?

[Jim Thompson]

On Sat, 12 Aug 2017 20:00:13 -0400, "Michael A. Terrell"

<mike.t...@earthlink.net> wrote:

>k...@notreal.com wrote:
>> On Sat, 12 Aug 2017 18:00:05 -0400, "Michael A. Terrell"
>> <mike.t...@earthlink.net> wrote:
>>
>>> Jim Thompson wrote:
>>>> On Sat, 12 Aug 2017 09:37:14 -0400, bitrex
>>>> <bit...@de.lete.earthlink.net> wrote:
>>>>
>>>>> The Chevy Volt's backup camera is ok under normal lighting conditions,
>>>>> but at night if someone is parked behind me and has LED or HID
>>>>> headlights on, there's so much lens flare/glare/CCD overdrive/whatever
>>>>> that you can't see a blessed thing and it becomes nearly unusable.
>>>>>
>>>>> Any suggestions for an expedient fix or a good aftermarket camera where
>>>>> this is less of a problem, if not possible?
>>>>
>>>> Get a real car >:-}
>>>
>>>
>>>
>>> They would have to take away Biterex's Y chromosome.
>>
>> There is none to take away.
>
>
> Just the photos in his purse?

Damn't Michael, You _must_ learn to be politically correct... the
correct pronoun usage now is "s'he'it" >:-}

[Michael A. Terrell]

Jim Thompson wrote:
> On Sat, 12 Aug 2017 20:00:13 -0400, "Michael A. Terrell"
> <mike.t...@earthlink.net> wrote:
>
>> k...@notreal.com wrote:
>>> On Sat, 12 Aug 2017 18:00:05 -0400, "Michael A. Terrell"
>>> <mike.t...@earthlink.net> wrote:
>>>
>>>> Jim Thompson wrote:
>>>>> On Sat, 12 Aug 2017 09:37:14 -0400, bitrex
>>>>> <bit...@de.lete.earthlink.net> wrote:
>>>>>
>>>>>> The Chevy Volt's backup camera is ok under normal lighting conditions,
>>>>>> but at night if someone is parked behind me and has LED or HID
>>>>>> headlights on, there's so much lens flare/glare/CCD overdrive/whatever
>>>>>> that you can't see a blessed thing and it becomes nearly unusable.
>>>>>>
>>>>>> Any suggestions for an expedient fix or a good aftermarket camera where
>>>>>> this is less of a problem, if not possible?
>>>>>
>>>>> Get a real car >:-}
>>>>
>>>>
>>>>
>>>> They would have to take away Biterex's Y chromosome.
>>>
>>> There is none to take away.
>>
>>
>> Just the photos in his purse?
>
> Damn't Michael, You _must_ learn to be politically correct... the
> correct pronoun usage now is "s'he'it" >:-}

You misspelled 'Excrement'.

[amdx]

Back when I got my first job in electronics about 44 years ago, the
company I worked for installed video cameras around factories. One of
the problems was a night, headlights would wash out the entire picture.
This was in the days of vidicon tubes. One of the techs built a little
circuit that would clamp anything above 1V to 0V. So a car with
headlights coming at you just had two black circles on the front
and everything else looked fine. It worked perfectly, it was really slick.
I don't have a clue whether this is possible with the electronics of a
backup camera.
Mikek

[k...@notreal.com]

What happened in daylight?

> I don't have a clue whether this is possible with the electronics of a
>backup camera.

There are no (exposed) analog signals, so it's more difficult than
that. There is also a problem of the carriers leaking from one cell
to another so it's a complicated problem. More expensive sensors have
a larger dynamic range but "expensive" and "automotive" don't go well
together.

[Jim Thompson]

On Sat, 12 Aug 2017 20:39:01 -0500, amdx <noj...@knology.net> wrote:

I've done some chip designs for controlling surveillance cameras...
iris control was a section of the chip.

[Jeff Liebermann]

On Sat, 12 Aug 2017 20:39:01 -0500, amdx <noj...@knology.net> wrote:

> Back when I got my first job in electronics about 44 years ago, the
>company I worked for installed video cameras around factories. One of
>the problems was a night, headlights would wash out the entire picture.
> This was in the days of vidicon tubes. One of the techs built a little
>circuit that would clamp anything above 1V to 0V. So a car with
>headlights coming at you just had two black circles on the front
>and everything else looked fine. It worked perfectly, it was really slick.
> I don't have a clue whether this is possible with the electronics of a
>backup camera.
> Mikek

Yes, it's possible. Most backup cameras run composite video. If the
cable from the camera to the display is a 75ohm coax cable, it's
composite video. The video signal from todays backup camera is
exactly the same as what was produced by the vidicon.

Incidentally, you have the voltages backwards. +0.075v is white,
+1.0v is black, 0v is blanking, and -0.4v is sync. You want to switch
anything that goes down to around +0.075v to +1.0V (and ignore the
color burst at 3.58MHz). A simple comparator should do the trick.

The modern version is an LPR (license plate recognition) camera. Some
work as you describe by converting an overload to black as in HLC
(head light compensation):
<https://kintronics.com/how-alpr-works/>
<https://www.youtube.com/watch?v=IKQ6RTcUuic>
Others have video compressors, that produce WDR (wide dynamic range)
video. You still see the high level whites, but not with as much
flare and glare. Overall dynamic range and contrast can also be
improved with an auto-iris lens and switching from color to b&w in low
light.
<https://www.google.com/search?tbm=isch&q=auto+iris+lens>
Some of these operate by sniffing the composite video and might be
retrofitted to a backup camera. (Hint: Watch out for the connector
wiring. While everyone uses the same 4 pin molded or DIN connector,
not everyone uses the same pinout).

I should be easy enough to add the circuit you describe into the
composite video line of an existing backup camera. I couldn't find a
patent for it.

--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[bitrex]

Very interesting!

[Jeff Liebermann]

On Sat, 12 Aug 2017 22:42:44 -0400, bitrex
<bit...@de.lete.earthlink.net> wrote:
>Very interesting!

Yep, but I made a mistake and this is not going to be as simple as I
originally suspected.

The old vidicon tube was b&w only as is today's b&w composite video.
However, backup cameras are now color, which is not quite the same
waveform. That's why I mentioned the color burst, which appears just
after the sync pulse and is centered around 0.0v. If a simple
comparator is used to trigger on something near +0.075v, it may also
trigger on the color burst and mangle the waveform and picture. I'm
not quite sure how to avoid that problem. Maybe a one-shot or timer
that's triggered by the sync pulse, and times out after the color
burst, when it's safe to switch the video to +1.0v (black).

Unfortunately, methinks that your 2017(?) Chevy Volt does not use
composite video. It might use the GM-LVDS interface:
<https://navtv.com/products/category/2/make/10/model/472/year/2017/version/2/back-up-camera-interface_chevrolet_volt_2017_usa.html>
So, if you want to add inputs, outputs, or additional circuitry to the
interface, you need an interface box:
<https://navtv.com/products/category/2/back-up-camera-interface.html>
There are two for the 2017 Chevy Volt:
<https://navtv.com/products/category/2/make/10/model/472/year/2017/version/2/back-up-camera-interface_chevrolet_volt_2017_usa.html>
You won't like the prices.

[Carl Ijames]

wrote in message news:gg0voctm13lkjdfu8...@4ax.com...

===========================================================

Exactly like sunglasses. I don't know that his camera doesn't have the
dynamic range for this to work. I have a cheap backup camera and it seems
to have a reasonable dynamic range, so there might be a happy medium where
just enough of a neutral density filter cuts the glare at night but still
leaves a useable picture day and night, and if so, that's the cheapest,
easiest solution and only takes a few minutes of testing to evaluate.

--
Regards,
Carl Ijames

[rickman]

Jeff Liebermann wrote on 8/12/2017 10:38 PM:
> On Sat, 12 Aug 2017 20:39:01 -0500, amdx <noj...@knology.net> wrote:
>
>> Back when I got my first job in electronics about 44 years ago, the
>> company I worked for installed video cameras around factories. One of
>> the problems was a night, headlights would wash out the entire picture.
>> This was in the days of vidicon tubes. One of the techs built a little
>> circuit that would clamp anything above 1V to 0V. So a car with
>> headlights coming at you just had two black circles on the front
>> and everything else looked fine. It worked perfectly, it was really slick.
>> I don't have a clue whether this is possible with the electronics of a
>> backup camera.
>> Mikek
>
> Yes, it's possible. Most backup cameras run composite video. If the
> cable from the camera to the display is a 75ohm coax cable, it's
> composite video. The video signal from todays backup camera is
> exactly the same as what was produced by the vidicon.
>
> Incidentally, you have the voltages backwards. +0.075v is white,
> +1.0v is black, 0v is blanking, and -0.4v is sync. You want to switch
> anything that goes down to around +0.075v to +1.0V (and ignore the
> color burst at 3.58MHz). A simple comparator should do the trick.

How would this help? It would replace the white flare with black, still
blotting out the image. Flare is an optical effect where the light bounces
off the black surfaces of the camera or reflects off the lens surfaces
enough to blot out the image. Once it is in the signal path there is
nothing you can do to recover the image. A better camera is needed or at
least a better lens or filter.

--

Rick C

[k...@notreal.com]

Yes, they're mixed signal chips. The outputs are some sort of
standardized digital interface (MIPI, parallel BT.656, WiSPi, or some
such). Some are even adding the video processing DSPs to the sensor
chip.

[bitrex]

On 08/13/2017 01:03 AM, Jeff Liebermann wrote:
> On Sat, 12 Aug 2017 22:42:44 -0400, bitrex
> <bit...@de.lete.earthlink.net> wrote:
>> Very interesting!
>
> Yep, but I made a mistake and this is not going to be as simple as I
> originally suspected.
>
> The old vidicon tube was b&w only as is today's b&w composite video.
> However, backup cameras are now color, which is not quite the same
> waveform. That's why I mentioned the color burst, which appears just
> after the sync pulse and is centered around 0.0v. If a simple
> comparator is used to trigger on something near +0.075v, it may also
> trigger on the color burst and mangle the waveform and picture. I'm
> not quite sure how to avoid that problem. Maybe a one-shot or timer
> that's triggered by the sync pulse, and times out after the color
> burst, when it's safe to switch the video to +1.0v (black).

Sounds like you'd basically have to use some dedicated IC to separate
out the sync and luminance for processing and then composite them back.
ICs like that aren't hard to come by but yeah, not so simple.

It got me thinking about "video compression" though, not in the sense of
data compression but dynamic range compression, like an audio
compressor. Like a feedback compressor with a filter in the control
signal such that it has a different "knee" for low and high amplitude
signal, but doesn't chop the high amplitude signals completely, then
followed by an expander to restore the dynamic range of the low
amplitude stuff.

There are a few articles online about stuff like that, apparently
dynamic range compressing video while maintaining other
bandwidth-related qualities like sharpness is a non-trivial problem and
there are algorithms (probably patented) implemented in FPGAs and uPs to
handle it.

I don't know if there are any commercial analog ICs that have the
bandwidth to do audio-like compression of composite video signals.

> Unfortunately, methinks that your 2017(?) Chevy Volt does not use
> composite video. It might use the GM-LVDS interface:
> <https://navtv.com/products/category/2/make/10/model/472/year/2017/version/2/back-up-camera-interface_chevrolet_volt_2017_usa.html>
> So, if you want to add inputs, outputs, or additional circuitry to the
> interface, you need an interface box:
> <https://navtv.com/products/category/2/back-up-camera-interface.html>
> There are two for the 2017 Chevy Volt:
> <https://navtv.com/products/category/2/make/10/model/472/year/2017/version/2/back-up-camera-interface_chevrolet_volt_2017_usa.html>
> You won't like the prices.

Blech! Cheaper to just try to find a better camera that already
incorporates some kind of dynamic range processing.

[George Herold]

On Saturday, August 12, 2017 at 9:37:25 AM UTC-4, bitrex wrote:
> The Chevy Volt's backup camera is ok under normal lighting conditions,
> but at night if someone is parked behind me and has LED or HID
> headlights on, there's so much lens flare/glare/CCD overdrive/whatever
> that you can't see a blessed thing and it becomes nearly unusable.
>
> Any suggestions for an expedient fix or a good aftermarket camera where
> this is less of a problem, if not possible?

Use the mirror's on you car? Or just turn your head and look. :^)
I'm guessing any 'fix' will screw up the daylight performance.
(I use cheap back-up monitors and CCD camera's to look at physics
stuff in the NIR, (~800nm) to get a good image I often have to
screw around with the various light levels.)

George H.

[k...@notreal.com]

On Sun, 13 Aug 2017 08:20:20 -0700 (PDT), George Herold
<ghe...@teachspin.com> wrote:

>On Saturday, August 12, 2017 at 9:37:25 AM UTC-4, bitrex wrote:
>> The Chevy Volt's backup camera is ok under normal lighting conditions,
>> but at night if someone is parked behind me and has LED or HID
>> headlights on, there's so much lens flare/glare/CCD overdrive/whatever
>> that you can't see a blessed thing and it becomes nearly unusable.
>>
>> Any suggestions for an expedient fix or a good aftermarket camera where
>> this is less of a problem, if not possible?
>
>Use the mirror's on you car? Or just turn your head and look. :^)
>I'm guessing any 'fix' will screw up the daylight performance.

*AND* night time performance.

>(I use cheap back-up monitors and CCD camera's to look at physics
>stuff in the NIR, (~800nm) to get a good image I often have to
>screw around with the various light levels.)

Good ones have a pretty good dynamic range (new ones are pretty
amazing). Cheap cameras are just that.

[Jeff Liebermann]

On Sun, 13 Aug 2017 10:16:24 -0400, bitrex
<bit...@de.lete.earthlink.net> wrote:

>Sounds like you'd basically have to use some dedicated IC to separate
>out the sync and luminance for processing and then composite them back.
>ICs like that aren't hard to come by but yeah, not so simple.

I think my trick of blocking any clamping until after the sync pulse
and chroma burst might work. If not, you're right. One would need to
seperate out the various video signal components, massage the
luminance, and put everything back together again. Not fun.

>It got me thinking about "video compression" though, not in the sense of
>data compression but dynamic range compression, like an audio
>compressor. Like a feedback compressor with a filter in the control
>signal such that it has a different "knee" for low and high amplitude
>signal, but doesn't chop the high amplitude signals completely, then
>followed by an expander to restore the dynamic range of the low
>amplitude stuff.

You just described HDR (high dynamic range) photogrphy:
<https://en.wikipedia.org/wiki/High-dynamic-range_imaging>

>There are a few articles online about stuff like that, apparently
>dynamic range compressing video while maintaining other
>bandwidth-related qualities like sharpness is a non-trivial problem and
>there are algorithms (probably patented) implemented in FPGAs and uPs to
>handle it.
>
>I don't know if there are any commercial analog ICs that have the
>bandwidth to do audio-like compression of composite video signals.

Just about every CCTV camera has built in AGC (automagic gain
control), a form of compression, usually with adjustable threshold and
gain. For example:
<https://www.maximintegrated.com/en/app-notes/index.mvp/id/4019>
(Yes, I know the chip is obsolete).

>> Unfortunately, methinks that your 2017(?) Chevy Volt does not use
>> composite video. It might use the GM-LVDS interface:
>> <https://navtv.com/products/category/2/make/10/model/472/year/2017/version/2/back-up-camera-interface_chevrolet_volt_2017_usa.html>
>> So, if you want to add inputs, outputs, or additional circuitry to the
>> interface, you need an interface box:
>> <https://navtv.com/products/category/2/back-up-camera-interface.html>
>> There are two for the 2017 Chevy Volt:
>> <https://navtv.com/products/category/2/make/10/model/472/year/2017/version/2/back-up-camera-interface_chevrolet_volt_2017_usa.html>
>> You won't like the prices.

>Blech! Cheaper to just try to find a better camera that already
>incorporates some kind of dynamic range processing.

Yep. Buy a cheap 3rd party backup camera and monitor kit. The camera
will probably use composite video, which should make the previously
mentioned video clamping techniques work.

I'm trying to determine what's inside the GM or Volt camera box. LVDS
(low voltage differential signaling or TIA/EIA-644) is just the
interface specification.

More:

"LVDS Offers Robust Video Interface for Automotive Applications"
<https://www.maximintegrated.com/en/app-notes/index.mvp/id/4019>

"MT9V032 LVDS camera board"
<https://danstrother.com/2011/01/14/mt9v032-lvds-camera-board/>
Beyond raw sensitivity, the MT9V032 supports a form of
high-dynamic-range exposures. By progressively reducing
the sensitivity of its pixels over the course of an exposure,
the sensor is able to approximate a non-linear response.
This significantly increases the dynamic range that the
sensor can capture in a single exposure - making it much
easier to operate in environments with wildly varying
lighting conditions (e.g. outside on a sunny day).


Disclaimer: I have a few fundamental incompetences. Unfortunately,
video is one of these.

[k...@notreal.com]

On Sat, 12 Aug 2017 19:38:34 -0700, Jeff Liebermann <je...@cruzio.com>
wrote:

>On Sat, 12 Aug 2017 20:39:01 -0500, amdx <noj...@knology.net> wrote:
>
>> Back when I got my first job in electronics about 44 years ago, the
>>company I worked for installed video cameras around factories. One of
>>the problems was a night, headlights would wash out the entire picture.
>> This was in the days of vidicon tubes. One of the techs built a little
>>circuit that would clamp anything above 1V to 0V. So a car with
>>headlights coming at you just had two black circles on the front
>>and everything else looked fine. It worked perfectly, it was really slick.
>> I don't have a clue whether this is possible with the electronics of a
>>backup camera.
>> Mikek
>
>Yes, it's possible. Most backup cameras run composite video.

Crappy ones are composite video. The better/newer ones are HD and use
some flavor of LVDS interface. There is a lot of work being done in
this area these days.

[Chris]

On 12/08/2017 11:37 PM, bitrex wrote:
> The Chevy Volt's backup camera is ok under normal lighting conditions,
> but at night if someone is parked behind me and has LED or HID
> headlights on, there's so much lens flare/glare/CCD overdrive/whatever
> that you can't see a blessed thing and it becomes nearly unusable.
>
> Any suggestions for an expedient fix or a good aftermarket camera where
> this is less of a problem, if not possible?

Daylight-cut IR filter?

Might need to supplement with IR illumination...

--
Chris.

[k...@notreal.com]

On Sun, 13 Aug 2017 01:27:39 -0400, "Carl Ijames"

Not quite like sunglasses. I can take sunglasses off when I walk in
the house.

No matter how slight the filtering is, it will increase dark noise,
this impeding night vision. I wouldn't want to be the owner of the
car who modified the system and than ran someone over because (or not)
of the modification.

[bitrex]

On 08/13/2017 07:12 PM, Jeff Liebermann wrote:

> Disclaimer: I have a few fundamental incompetences. Unfortunately,
> video is one of these.

Like vacuum tubes and bellbottoms analog video mostly falls under
"before my time"

[bitrex]

Cars aren't made to see out of anymore, it'd actually be nice to have a
camera on the front too so I can actually see how far in front of me the
curb is when parking.

[mako...@yahoo.com]

>
> It got me thinking about "video compression" though, not in the sense of
> data compression but dynamic range compression, like an audio
> compressor.

Google the term "Gamma"

mark

[amdx]

It only clamped signals that shot over 1V to 0V*, so white was OK,
whiter than white was clamped to black.

* or was that 0.3V?

Mikek

[rickman]

Why would it matter what level it was clamped to? If it's whiter than
white, I would think clamping it to white would be fine.

--

Rick C

[amdx]

On 8/12/2017 9:38 PM, Jeff Liebermann wrote:
> On Sat, 12 Aug 2017 20:39:01 -0500, amdx <noj...@knology.net> wrote:
>
>> Back when I got my first job in electronics about 44 years ago, the
>> company I worked for installed video cameras around factories. One of
>> the problems was a night, headlights would wash out the entire picture.
>> This was in the days of vidicon tubes. One of the techs built a little
>> circuit that would clamp anything above 1V to 0V. So a car with
>> headlights coming at you just had two black circles on the front
>> and everything else looked fine. It worked perfectly, it was really slick.
>> I don't have a clue whether this is possible with the electronics of a
>> backup camera.
>> Mikek
>
> Yes, it's possible. Most backup cameras run composite video. If the
> cable from the camera to the display is a 75ohm coax cable, it's
> composite video. The video signal from todays backup camera is
> exactly the same as what was produced by the vidicon.
>
> Incidentally, you have the voltages backwards. +0.075v is white,
> +1.0v is black, 0v is blanking, and -0.4v is sync. You want to switch
> anything that goes down to around +0.075v to +1.0V (and ignore the
> color burst at 3.58MHz). A simple comparator should do the trick.
>

I'm sure it depends on the system and where in the system you measure,
But from '73' to '94' all the video outputs I looked at were 1Vpp, the
sync was 0.3V and the video information was 0.7V. I will give you that
Black sat at 0V, white at 0.7V and sync was minus 0.3V.
Like this. >
https://cdn6.bigcommerce.com/s-8em24nxp/product_images/uploaded_images/m246d7c6a.jpg

But, I can back up what you say with this.
> https://sites.google.com/site/muhammadsohailnafees/tv-theory/composite-video-signal
That's not my experience though.

Mikek

[amdx]

Ya, maybe with today's sets, but I seem to recall our B/W monitors
would also flare on bright objects. All I can say is it turned headlight
images and parking lot lighting black and made the rest of the picture
viewable. Back then this was a big deal to security guards setting in
their shack watching the factory. Even had windshield wipers on the
camera housings, and a fan for hot days.
Mikek

[Jeff Liebermann]

On Mon, 14 Aug 2017 18:00:55 -0500, amdx <noj...@knology.net> wrote:

>On 8/12/2017 9:38 PM, Jeff Liebermann wrote:
>> Incidentally, you have the voltages backwards. +0.075v is white,
>> +1.0v is black, 0v is blanking, and -0.4v is sync. You want to switch
>> anything that goes down to around +0.075v to +1.0V (and ignore the
>> color burst at 3.58MHz). A simple comparator should do the trick.

> I'm sure it depends on the system and where in the system you measure,
>But from '73' to '94' all the video outputs I looked at were 1Vpp, the
>sync was 0.3V and the video information was 0.7V. I will give you that
>Black sat at 0V, white at 0.7V and sync was minus 0.3V.
>Like this. >
>https://cdn6.bigcommerce.com/s-8em24nxp/product_images/uploaded_images/m246d7c6a.jpg
>
>But, I can back up what you say with this.
>> https://sites.google.com/site/muhammadsohailnafees/tv-theory/composite-video-signal
>That's not my experience though.
>
> Mikek

I wasn't sure of the voltage levels so I looked it up with a Google
image search before posting.
<https://www.google.com/search?tbm=isch&q=composite+video+waveform>
I don't recall which image I used, but here's a few that agree with my
-0.4v sync voltage levels:
<http://www.nutsvolts.com/uploads/wygwam/NV_0105_Jack_Figure01.jpg>
<https://i.stack.imgur.com/3KbGf.png>
<https://hackadaycom.files.wordpress.com/2015/11/composite_color_figure_02.png?w=400&h=289>
<https://www.maximintegrated.com/en/app-notes/index.mvp/id/3823>

and here are some more that agree with your -0.3v sync voltage:
<http://martin.hinner.info/vga/An1-3.jpg>
<http://web.onetel.com/~uncletony/images/video-signal.gif>
<http://www.causewaysecuritysolutions.com/uploads/1/6/8/8/16884516/1731451_orig.jpg>
<http://www.batsocks.co.uk/img/info_video/Timing_PAL_H-Blanking.gif>
<http://www.rennes.supelec.fr/ren/perso/jweiss/tv/signal/image85.gif>

or, perhaps you might like a -0.5v sync pulse?
<http://s.hswstatic.com/gif/tv-line.gif>

When in doubt, there's Wikipedia:
<https://en.wikipedia.org/wiki/Composite_video>
<https://en.wikipedia.org/wiki/Composite_video#/media/File:Composite_Video.svg>
which shows something quite different from any of the above
contenders. So much for Wikipedia.

Well, maybe EIA RS-170 (for b&w video):
<http://ee-classes.usc.edu/ee459/library/documents/RS170.pdf>
See Detail YY on Page 13 of 15. -0.4v sync pulse.

It this is where I stole my numbers:
<http://www.epanorama.net/documents/video/rs170.html>
White: +1.000 V
Black: +0.075 V
Blank: (0V reference)
Sync: -0.400 V

My guess(tm) is that we might be looking at the difference between
composite video as delivered over a CCTV coax cable, versus composite
video as delivered by a video broadcast transmitter, where the
negative voltage sync pulse cannot go below zero. Or, everyong doing
video is derranged.

[Michael A. Terrell]

NTSC broadcast video inverted the video, so the sync tips were the
highest output level. That is why a weak signal showed white 'snow'
instead of a black screen.

It did use .4V for the sync. Look at the manual for a Tektronix 529
or RM529. I worked with the RM529 at multiple TV stations, over the
decades, and I still have one out in my shop.