Ir illuminators...

[Phil Hobbs]

John Larkin <jjlarkin@highlandtechnology.com> wrote:

On Wed, 13 Sep 2023 15:35:37 -0000 (UTC), Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Joe Gwinn <joegwinn@comcast.net> wrote:
On Wed, 13 Sep 2023 07:51:50 -0700, John Larkin
jjlarkin@highlandtechnology.com> wrote:

On Wed, 13 Sep 2023 13:57:07 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

Don Y <blockedofcourse@foo.invalid> wrote:

[...] I can afford to move the
emitters *out* of the camera (and disable any that are internal)

In my experience that is by far the best thing to do.

Having the emitters inside the camera housing causes reflection off the
window which reduces the contrast of the scene. If the window \'fogs\',
even slightly, the scene will almost \'white-out\'. If the camera is
outdoors and there is the slightest mist, the light will be reflected by
the droplets straight back into the camera lens making it unusable.

The illumination needs to come from the sides or above or below --
anywhere except directly in line with the camera. Slight shadows will
also give a 3D effect which helps with recognising people and objects.

Why do evil robots in movies have eyes that glow? That\'s bad optics.

X-Ray vision?


It’s only bad if it’s unmodulated CW.

Cheers

Phil Hobbs

I suppose the illuminator could be nanosecond pulsed and the imager
fast-gated. Get some time-of-flight data too. Maybe some advanced
civilization could do that.

That’s more or less my current project.

“Any technology that is distinguishable from magic is insufficiently
advanced.”

But more likely, movies do that to make evil robots look more evil.
Good robots don\'t have eyes that glow.


Cheers

Phil Hobbs



--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

 

[Don Y]

On 9/13/2023 5:57 AM, Liz Tuddenham wrote:

Don Y <blockedofcourse@foo.invalid> wrote:

[...] I can afford to move the
emitters *out* of the camera (and disable any that are internal)

In my experience that is by far the best thing to do.

The downside is that it means making another enclosure for the illuminators.

Having the emitters inside the camera housing causes reflection off the
window which reduces the contrast of the scene. If the window \'fogs\',
even slightly, the scene will almost \'white-out\'. If the camera is
outdoors and there is the slightest mist, the light will be reflected by
the droplets straight back into the camera lens making it unusable.

The cameras I am most likely going to modify have the optics
using a (center) portion of the glass shielded from the light of the
emitters. There\'s a cylindrical \"condom\" that slides around the
optical lens *inside* the glass-enclosed case.

I am most worried about the power dissipation in the (hermetic) case
as I\'ll be \"strobing\" the emitters to further reduce power
consumption (e.g., overdrive them at a low frame rate by syncing
their drive to the video -- \"notice\" where the light is apparent in
the frame and retard/advance until it aligns with the timing of
a frame)

Once I \"see\" something of interest, I can increase the rate and
decrease the drive as the subject moves into the field of interest
(or, leave it at the reduced frame rate/increased range if
the subject doesn\'t approach)

The illumination needs to come from the sides or above or below --
anywhere except directly in line with the camera. Slight shadows will
also give a 3D effect which helps with recognising people and objects.

I have to coordinate the actions of multiple cameras that
overlap the scene(s) so will similarly have to synchronize
illuminators (when operating at lowered frame rates).

(True) recognition is only required \"close in\" -- e.g., if you approach
the front door, I\'ll have a clearer view of your face/features/size
so less reliant on stressing the illuminators (and, more willing to
expend power budget as there is a potential for results)

 

[Don Y]

On 9/13/2023 8:55 AM, Liz Tuddenham wrote:

Why did the reversing cameras in my van come with I.R. illuminators
built-in?

Hmmmm... odd, that. The cameras on SWMBO\'s vehicle are just
bare optics, relying on the (LED) brake and backup lights
for scene lighting.

[And gives me a straightforward way to present live video
on that monitor without having to reverse engineer the
entire navigation head!]

I had to dismantle the cameras and disconnect the L.E.D.s before they
would work properly in dim light. Now the 21-watt reversing lamp gives
more than enough light for the cameras to work properly, even in fog or
heavy rain.

Was this an aftermarket product?

 

[John Larkin]

On Wed, 13 Sep 2023 17:35:38 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin <jjlarkin@highlandtechnology.com> wrote:
On Wed, 13 Sep 2023 15:35:37 -0000 (UTC), Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Joe Gwinn <joegwinn@comcast.net> wrote:
On Wed, 13 Sep 2023 07:51:50 -0700, John Larkin
jjlarkin@highlandtechnology.com> wrote:

On Wed, 13 Sep 2023 13:57:07 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

Don Y <blockedofcourse@foo.invalid> wrote:

[...] I can afford to move the
emitters *out* of the camera (and disable any that are internal)

In my experience that is by far the best thing to do.

Having the emitters inside the camera housing causes reflection off the
window which reduces the contrast of the scene. If the window \'fogs\',
even slightly, the scene will almost \'white-out\'. If the camera is
outdoors and there is the slightest mist, the light will be reflected by
the droplets straight back into the camera lens making it unusable.

The illumination needs to come from the sides or above or below --
anywhere except directly in line with the camera. Slight shadows will
also give a 3D effect which helps with recognising people and objects.

Why do evil robots in movies have eyes that glow? That\'s bad optics.

X-Ray vision?


It?s only bad if it?s unmodulated CW.

Cheers

Phil Hobbs

I suppose the illuminator could be nanosecond pulsed and the imager
fast-gated. Get some time-of-flight data too. Maybe some advanced
civilization could do that.

That’s more or less my current project.

Single-photon timestamp imagers would be cool, much better than charge
integration with occasional readout and dump. But they would create a
lot of data.

Local processing would help. Where have I heard that idea before?

 

[Joe Gwinn]

On Wed, 13 Sep 2023 12:17:38 -0700, John Larkin
<jjlarkin@highlandtechnology.com> wrote:

On Wed, 13 Sep 2023 17:35:38 -0000 (UTC), Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin <jjlarkin@highlandtechnology.com> wrote:
On Wed, 13 Sep 2023 15:35:37 -0000 (UTC), Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Joe Gwinn <joegwinn@comcast.net> wrote:
On Wed, 13 Sep 2023 07:51:50 -0700, John Larkin
jjlarkin@highlandtechnology.com> wrote:

On Wed, 13 Sep 2023 13:57:07 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

Don Y <blockedofcourse@foo.invalid> wrote:

[...] I can afford to move the
emitters *out* of the camera (and disable any that are internal)

In my experience that is by far the best thing to do.

Having the emitters inside the camera housing causes reflection off the
window which reduces the contrast of the scene. If the window \'fogs\',
even slightly, the scene will almost \'white-out\'. If the camera is
outdoors and there is the slightest mist, the light will be reflected by
the droplets straight back into the camera lens making it unusable.

The illumination needs to come from the sides or above or below --
anywhere except directly in line with the camera. Slight shadows will
also give a 3D effect which helps with recognising people and objects.

Why do evil robots in movies have eyes that glow? That\'s bad optics.

X-Ray vision?


It?s only bad if it?s unmodulated CW.

Cheers

Phil Hobbs

I suppose the illuminator could be nanosecond pulsed and the imager
fast-gated. Get some time-of-flight data too. Maybe some advanced
civilization could do that.

That’s more or less my current project.

Single-photon timestamp imagers would be cool, much better than charge
integration with occasional readout and dump. But they would create a
lot of data.

..<https://en.wikipedia.org/wiki/Ultra-wideband>


>Local processing would help. Where have I heard that idea before?

Every time XXX-as-a-service was proposed?

Joe Gwinn

 

[Liz Tuddenham]

Don Y <blockedofcourse@foo.invalid> wrote:

On 9/13/2023 8:55 AM, Liz Tuddenham wrote:
Why did the reversing cameras in my van come with I.R. illuminators
built-in?

Hmmmm... odd, that. The cameras on SWMBO\'s vehicle are just
bare optics, relying on the (LED) brake and backup lights
for scene lighting.

[And gives me a straightforward way to present live video
on that monitor without having to reverse engineer the
entire navigation head!]

I had to dismantle the cameras and disconnect the L.E.D.s before they
would work properly in dim light. Now the 21-watt reversing lamp gives
more than enough light for the cameras to work properly, even in fog or
heavy rain.

Was this an aftermarket product?

Yes, I installed them myself. I tried to get some without LEDs or with
a separate illumination circuit, but they all have the same design
fault.

You can see them in the picture captioned \"Cowl Over Ventilation Holes\"
at:
http://www.poppyrecords.co.uk/Van/vanconversion.htm
They are at the top of the back doors near the centre line.


--
~ Liz Tuddenham ~
(Remove the \".invalid\"s and add \".co.uk\" to reply)
www.poppyrecords.co.uk

 

[Don Y]

On 9/13/2023 1:01 PM, Liz Tuddenham wrote:

Was this an aftermarket product?

Yes, I installed them myself. I tried to get some without LEDs or with
a separate illumination circuit, but they all have the same design
fault.

Are they marketed as \"backup cameras\"? Or, as just \"generic cameras\"?
(i.e., in the former case, they should have been able to EXPECT external
lighting to be present; in the latter, not)

Part of the problem of using an external illuminator is I
would need to be able to disable the \"internal\" ones,
yet keep the Ir filter controls (ideally, made external).

[I\'m looking at large enough quantities that I can probably just
design what I want and get someone to build them for me. Silly
for folks to put smarts -- CPU, NIC, magnetics, etc. -- in a camera
and then not do any real processing beyond \"motion detected\"
(YOU looked at the scene; tell me what *I* want to know!)]

You can see them in the picture captioned \"Cowl Over Ventilation Holes\"
at:
http://www.poppyrecords.co.uk/Van/vanconversion.htm
They are at the top of the back doors near the centre line.

 

[Jasen Betts]

On 2023-09-12, Don Y <blockedofcourse@foo.invalid> wrote:

On 9/12/2023 12:28 AM, Martin Brown wrote:
On 11/09/2023 22:50, Don Y wrote:
I have lots of cameras in my current design (solve problem once, apply
many times!).

Most instances require Ir illuminators (I am trying to standardize on
a single device \"used appropriately\" instead of different devices
for the different applications).

I\'d like to save power on the illuminators.

Decide what signal to noise in the video image is acceptable for your
application and use only that much artificial light.

I\'m trying to come up with *one* camera that I can \"adjust\"
to suit different scenes.

One approach is to drive the entire \"illuminator\" with different
current levels to get varying intensity output.

Another approach is to drive varying *numbers* of emitters
(at fixed drive levels).

If you get down to 1 or 2 LEDs then that is a whole stop difference in
exposure, but once you go up to 2 or more LEDs you can get exposure right to
the nearest half stop which is good enough for all practical purposes (even
back in the days of conventional film).

You effectively want a sequence of LEDs lit up along the lines of:

2 3 4 6 8 11 16 22 32

just like the old f stops on a classical camera.

The cameras I\'ve found (so far) tend to have a lot of emitters
(the one I toredown tonight had ~40). I can afford to move the
emitters *out* of the camera (and disable any that are internal)
but still need the Ir filter, inside, to be operable.

Beware that if they are too far off axis the lighting profile might change as
you switch more distant ones on and off.

Yes but most seem to be arranged in concentric rings.
I suspect the large numbers are intended just to boost range.

[In each case, closing the loop with video feedback to ensure
I\'m not over-illuminating the scene]

Suggestions as to which will give me most *effective* control
vs. power dissipated?

Using the least amount of illumination you can get away with.

The question is whether that can be obtained by running a bunch
of emitters at a low current *or* a fewer number at a higher
current.

Then the answer is YES!


However curreent can be varied in more steps than emitter count can.




--
Jasen.
🇺🇦 Слава Україні

 

[Jasen Betts]

On 2023-09-13, John Larkin <jjlarkin@highlandtechnology.com> wrote:

On Wed, 13 Sep 2023 13:57:07 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

Don Y <blockedofcourse@foo.invalid> wrote:

[...] I can afford to move the
emitters *out* of the camera (and disable any that are internal)

In my experience that is by far the best thing to do.

Having the emitters inside the camera housing causes reflection off the
window which reduces the contrast of the scene. If the window \'fogs\',
even slightly, the scene will almost \'white-out\'. If the camera is
outdoors and there is the slightest mist, the light will be reflected by
the droplets straight back into the camera lens making it unusable.

The illumination needs to come from the sides or above or below --
anywhere except directly in line with the camera. Slight shadows will
also give a 3D effect which helps with recognising people and objects.

Why do evil robots in movies have eyes that glow? That\'s bad optics.

Arthur C. Clarke and Stanley Kubrick started it.

https://villains.fandom.com/wiki/HAL_9000



--
Jasen.
🇺🇦 Слава Україні

 

[Liz Tuddenham]

Don Y <blockedofcourse@foo.invalid> wrote:

On 9/13/2023 1:01 PM, Liz Tuddenham wrote:
Was this an aftermarket product?

Yes, I installed them myself. I tried to get some without LEDs or with
a separate illumination circuit, but they all have the same design
fault.

Are they marketed as \"backup cameras\"? Or, as just \"generic cameras\"?
(i.e., in the former case, they should have been able to EXPECT external
lighting to be present; in the latter, not)

They were sold as \'Reversing cameras\' and came as a kit, with
appropriate long multicore cables and in-line connectors to allow them
to be installed in a vehicle.

Part of the problem of using an external illuminator is I
would need to be able to disable the \"internal\" ones,
yet keep the Ir filter controls (ideally, made external).

[I\'m looking at large enough quantities that I can probably just
design what I want and get someone to build them for me. Silly
for folks to put smarts -- CPU, NIC, magnetics, etc. -- in a camera
and then not do any real processing beyond \"motion detected\"
(YOU looked at the scene; tell me what *I* want to know!)]

That\'s far more complex than anything I have dealt with, but it still
needs the basic lighting set-up to be right before embarking on any sort
of software or human analysis.


--
~ Liz Tuddenham ~
(Remove the \".invalid\"s and add \".co.uk\" to reply)
www.poppyrecords.co.uk

 

[Don Y]

On 9/14/2023 1:36 PM, Liz Tuddenham wrote:

Don Y <blockedofcourse@foo.invalid> wrote:

Are they marketed as \"backup cameras\"? Or, as just \"generic cameras\"?
(i.e., in the former case, they should have been able to EXPECT external
lighting to be present; in the latter, not)

They were sold as \'Reversing cameras\' and came as a kit, with
appropriate long multicore cables and in-line connectors to allow them
to be installed in a vehicle.

So, no excuse for NOT having considered available illumination
(and, at least, a way of disabling the internal aspect).

Part of the problem of using an external illuminator is I
would need to be able to disable the \"internal\" ones,
yet keep the Ir filter controls (ideally, made external).

[I\'m looking at large enough quantities that I can probably just
design what I want and get someone to build them for me. Silly
for folks to put smarts -- CPU, NIC, magnetics, etc. -- in a camera
and then not do any real processing beyond \"motion detected\"
(YOU looked at the scene; tell me what *I* want to know!)]

That\'s far more complex than anything I have dealt with, but it still
needs the basic lighting set-up to be right before embarking on any sort
of software or human analysis.

Relying on a generic, COTS solution means you rely on that designer\'s
idea of \"right\".

I have several IP cameras with lots of \"smarts\"... but, only in the
generic sense. They let you statically define a \"field of interest\"
(masking out portions of the scene that are NOT of interest) and
will detect \"motion\" (changes) in those areas. But, won\'t tell
you if it\'s a person, pet, piece of sagebrush rolling past, etc.
The client must then analyze the video to see if it \"contains\"
items of interest.

[And, as nothing limits how often motion might be encountered,
the client has to be able to process video *continuously*. So,
what value to the camera\'s efforts?]

Sort of like the moths (some with wingspans of 6-8 inches!) that
flutter in front of neighbor\'s Nest security light -- causing it
to remain illuminated all night long!

[How is this any different from an *inexpensive* light that comes on
at sundown? What value the CPU *in* that light?]

Generic solutions are usually hit-or-miss at solving SPECIFIC
problems.

 

[Martin Brown]

On 13/09/2023 15:51, John Larkin wrote:

On Wed, 13 Sep 2023 13:57:07 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

Don Y <blockedofcourse@foo.invalid> wrote:

[...] I can afford to move the
emitters *out* of the camera (and disable any that are internal)

In my experience that is by far the best thing to do.

Having the emitters inside the camera housing causes reflection off the
window which reduces the contrast of the scene. If the window \'fogs\',
even slightly, the scene will almost \'white-out\'. If the camera is
outdoors and there is the slightest mist, the light will be reflected by
the droplets straight back into the camera lens making it unusable.

Ideally you want something to cast a rain shadow onto the camera lens or
window - something that not all motorway monitoring cameras have.

The illumination needs to come from the sides or above or below --
anywhere except directly in line with the camera. Slight shadows will
also give a 3D effect which helps with recognising people and objects.

Why do evil robots in movies have eyes that glow? That\'s bad optics.

Its a throwback to the old days of vidicon tubes which actually did glow
very slightly in the dark due to the readout electron beam.

Baddies and demons usually have red eyes too.
(eg I Robot, Planet of the Ood)


--
Martin Brown

 

[Don Y]

On 9/14/2023 2:58 PM, Martin Brown wrote:

Baddies and demons usually have red eyes too.
(eg I Robot, Planet of the Ood)

\"Erik\" (1920\'s) had red pupils painted on white lamps. Perhaps
someone decided that red lamps would be easier?

And, of course, Cylons would just look stupid with any other color!
(Marvin, OTOH, would look menacing in reds; N.B. Robby had no
discernible \"vision sensors\") Gort was monochromatic (and no mention
of eye color in the book) so any guess is as good as any other.

 

[Phil Hobbs]

On 2023-09-13 15:17, John Larkin wrote:> On Wed, 13 Sep 2023 17:35:38
-0000 (UTC), Phil Hobbs

pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin <jjlarkin@highlandtechnology.com> wrote:
On Wed, 13 Sep 2023 15:35:37 -0000 (UTC), Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Joe Gwinn <joegwinn@comcast.net> wrote:
On Wed, 13 Sep 2023 07:51:50 -0700, John Larkin
jjlarkin@highlandtechnology.com> wrote:

On Wed, 13 Sep 2023 13:57:07 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

Don Y <blockedofcourse@foo.invalid> wrote:

[...] I can afford to move the
emitters *out* of the camera (and disable any that are internal)

In my experience that is by far the best thing to do.

Having the emitters inside the camera housing causes reflection
off the
window which reduces the contrast of the scene. If the window
\'fogs\',
even slightly, the scene will almost \'white-out\'. If the camera is
outdoors and there is the slightest mist, the light will be
reflected by
the droplets straight back into the camera lens making it unusable.

The illumination needs to come from the sides or above or below --
anywhere except directly in line with the camera. Slight
shadows will
also give a 3D effect which helps with recognising people and
objects.

Why do evil robots in movies have eyes that glow? That\'s bad optics.

X-Ray vision?


It\'s only bad if it\'s unmodulated CW.



I suppose the illuminator could be nanosecond pulsed and the imager
fast-gated. Get some time-of-flight data too. Maybe some advanced
civilization could do that.

That’s more or less my current project.

Single-photon timestamp imagers would be cool, much better than charge
integration with occasional readout and dump. But they would create a
lot of data.

Local processing would help. Where have I heard that idea before?

There\'s a lidar company called Ouster that has patented the notion of
running SPADs straight into FPGA inputs, with no TIAs at all. The idea
is to improve the time resolution by time-stamping the detection events
and averaging over a lot of them to smear out the FPGA clock granularity.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[John Larkin]

On Thu, 14 Sep 2023 21:36:56 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

Don Y <blockedofcourse@foo.invalid> wrote:

On 9/13/2023 1:01 PM, Liz Tuddenham wrote:
Was this an aftermarket product?

Yes, I installed them myself. I tried to get some without LEDs or with
a separate illumination circuit, but they all have the same design
fault.

Are they marketed as \"backup cameras\"? Or, as just \"generic cameras\"?
(i.e., in the former case, they should have been able to EXPECT external
lighting to be present; in the latter, not)

They were sold as \'Reversing cameras\' and came as a kit, with
appropriate long multicore cables and in-line connectors to allow them
to be installed in a vehicle.


Part of the problem of using an external illuminator is I
would need to be able to disable the \"internal\" ones,
yet keep the Ir filter controls (ideally, made external).

[I\'m looking at large enough quantities that I can probably just
design what I want and get someone to build them for me. Silly
for folks to put smarts -- CPU, NIC, magnetics, etc. -- in a camera
and then not do any real processing beyond \"motion detected\"
(YOU looked at the scene; tell me what *I* want to know!)]

That\'s far more complex than anything I have dealt with, but it still
needs the basic lighting set-up to be right before embarking on any sort
of software or human analysis.

I\'d love to have a backup cam on my 2008 Audi, but installing the
camera and an LCD somewhere sounds nasty.

 

[Carl]

On 9/14/23 10:14 PM, John Larkin wrote:

On Thu, 14 Sep 2023 21:36:56 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

Don Y <blockedofcourse@foo.invalid> wrote:

On 9/13/2023 1:01 PM, Liz Tuddenham wrote:
Was this an aftermarket product?

Yes, I installed them myself. I tried to get some without LEDs or with
a separate illumination circuit, but they all have the same design
fault.

Are they marketed as \"backup cameras\"? Or, as just \"generic cameras\"?
(i.e., in the former case, they should have been able to EXPECT external
lighting to be present; in the latter, not)

They were sold as \'Reversing cameras\' and came as a kit, with
appropriate long multicore cables and in-line connectors to allow them
to be installed in a vehicle.


Part of the problem of using an external illuminator is I
would need to be able to disable the \"internal\" ones,
yet keep the Ir filter controls (ideally, made external).

[I\'m looking at large enough quantities that I can probably just
design what I want and get someone to build them for me. Silly
for folks to put smarts -- CPU, NIC, magnetics, etc. -- in a camera
and then not do any real processing beyond \"motion detected\"
(YOU looked at the scene; tell me what *I* want to know!)]

That\'s far more complex than anything I have dealt with, but it still
needs the basic lighting set-up to be right before embarking on any sort
of software or human analysis.

I\'d love to have a backup cam on my 2008 Audi, but installing the
camera and an LCD somewhere sounds nasty.

I figured that surely there was a wireless solution these days. This is
the first hit I got at Amazon for \"wireless car back up camera\":
https://www.amazon.com/Reverse-Vehicle-License-Suitable-Android/dp/B0C1V7VZCX,
$31. Camera is on a bar that goes across the top of the license plate,
uses wi-fi to talk to a smartphone app on iPhone or Android at 1080P.
Picture shows 3 wires but a couple of reviews say just +12 and ground.
Either find a +12 that\'s always hot when key is on if you want that, or
tap into one of the backup light feeds so it only comes on in reverse.
Oh, yeah, in honor of the other thread it has built-in IR LEDs .

--
Regards,
Carl

 

[Liz Tuddenham]

Martin Brown <\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 13/09/2023 15:51, John Larkin wrote:
On Wed, 13 Sep 2023 13:57:07 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

Don Y <blockedofcourse@foo.invalid> wrote:

[...] I can afford to move the
emitters *out* of the camera (and disable any that are internal)

In my experience that is by far the best thing to do.

Having the emitters inside the camera housing causes reflection off the
window which reduces the contrast of the scene. If the window \'fogs\',
even slightly, the scene will almost \'white-out\'. If the camera is
outdoors and there is the slightest mist, the light will be reflected by
the droplets straight back into the camera lens making it unusable.

Ideally you want something to cast a rain shadow onto the camera lens or
window - something that not all motorway monitoring cameras have.

Something like FIDO ?


--
~ Liz Tuddenham ~
(Remove the \".invalid\"s and add \".co.uk\" to reply)
www.poppyrecords.co.uk

 

[Liz Tuddenham]

Carl <carl.ijamesxx@yyverizon.net> wrote:

On 9/14/23 10:14 PM, John Larkin wrote:
On Thu, 14 Sep 2023 21:36:56 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

Don Y <blockedofcourse@foo.invalid> wrote:

On 9/13/2023 1:01 PM, Liz Tuddenham wrote:
Was this an aftermarket product?

Yes, I installed them myself. I tried to get some without LEDs or with
a separate illumination circuit, but they all have the same design
fault.

Are they marketed as \"backup cameras\"? Or, as just \"generic cameras\"?
(i.e., in the former case, they should have been able to EXPECT external
lighting to be present; in the latter, not)

They were sold as \'Reversing cameras\' and came as a kit, with
appropriate long multicore cables and in-line connectors to allow them
to be installed in a vehicle.


Part of the problem of using an external illuminator is I
would need to be able to disable the \"internal\" ones,
yet keep the Ir filter controls (ideally, made external).

[I\'m looking at large enough quantities that I can probably just
design what I want and get someone to build them for me. Silly
for folks to put smarts -- CPU, NIC, magnetics, etc. -- in a camera
and then not do any real processing beyond \"motion detected\"
(YOU looked at the scene; tell me what *I* want to know!)]

That\'s far more complex than anything I have dealt with, but it still
needs the basic lighting set-up to be right before embarking on any sort
of software or human analysis.

I\'d love to have a backup cam on my 2008 Audi, but installing the
camera and an LCD somewhere sounds nasty.


I figured that surely there was a wireless solution these days.

I considered that -- but as I was partly re-wiring the vehicle to
convert it into a stealth camper, it was more straighforward to just run
the extra cables. As you say [below], you still need a power feed.
The only snag was getting the moulded-on connectors through the
\'bellows\' cable ducts by the hinges of the back doors. I eventually cut
the cable, threaded it through and soldered it back together again.

Either find a +12 that\'s always hot when key is on if you want that, or
tap into one of the backup light feeds so it only comes on in reverse.

I removed the elaborate radio system and installed the screen in the
space that left in the dashboard, then added a toggle switch alongside
it, so I could switch it on when I needed it. Sometimes it is helpful
to be able to check what is going on behind the van when parked up. A
much simpler (but perfectly adequate) car radio is now installed on the
overhead parcel shelf.

There are two cameras, one giving a wide horizontal view and one giving
a downwards view for accurate parking. I had thought about the
possibility of switching on the LEDs in whichever camera wasn\'t in use
at the time, so each one became the other\'s illuminator. That would
have been done manually when necessary, not automatically at the speed
of light, as suggested by other contributors. Unfortunately it would
have needed an extra wire and would have meant replacing the wiring
going into the waterproof housings. I was trying to avoid too much
alteration or any extra risk of water ingress, so decided the extra
benefit (if indeed it was a benefit, because the cameras were so close
together) wasn\'t worth the risks.

--
~ Liz Tuddenham ~
(Remove the \".invalid\"s and add \".co.uk\" to reply)
www.poppyrecords.co.uk

 

[Martin Brown]

On 14/09/2023 08:46, Jasen Betts wrote:

On 2023-09-13, John Larkin <jjlarkin@highlandtechnology.com> wrote:
On Wed, 13 Sep 2023 13:57:07 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

Don Y <blockedofcourse@foo.invalid> wrote:


Why do evil robots in movies have eyes that glow? That\'s bad optics.

Arthur C. Clarke and Stanley Kubrick started it.

https://villains.fandom.com/wiki/HAL_9000

I think Terry Nation\'s Dr Who Daleks ~1964 were amongst the first evil
robots to have glowing eye stalks but what colour they were is hard to
say since it was B&W. Here is one rising out of the water under London.

https://en.wikipedia.org/wiki/The_Dalek_Invasion_of_Earth#/media/Filealek_Invasion_of_Earth.jpg

I suspect that on their first appearance in 1963 the eye stalks didn\'t
glow largely because the special effects had run out of time and money.

--
Martin Brown

 

[Martin Brown]

On 14/09/2023 08:36, Jasen Betts wrote:

On 2023-09-12, Don Y <blockedofcourse@foo.invalid> wrote:
On 9/12/2023 12:28 AM, Martin Brown wrote:

Suggestions as to which will give me most *effective* control
vs. power dissipated?

Using the least amount of illumination you can get away with.

The question is whether that can be obtained by running a bunch
of emitters at a low current *or* a fewer number at a higher
current.

Then the answer is YES!

However current can be varied in more steps than emitter count can.

But you only really need to control a photographic exposure to the
nearest stop ( power of two in power) or half stop if you are fussy.

Increasingly mobile phones take multiple images at different very short
exposures centred on nominal 1/4, 1, 4x to create an even higher dynamic
range - their sensors now are tiny with shallow electron wells.

--
Martin Brown