help needed - covert IR (no red glow) at 100 yards

[mike_va 0]

As a point of reference, here is a partial crop on a Axis P3344 at 1-60s and 21dB, with and without the big Bosch. Where the culdesac curves on the right side is about 50-60 yards out. The IR is just on the ground at the right side of the pic, you can see the shadows.

[rory 0]

The other remaining aspect will be if the lenses are corrected at 950 also...

 

Wish Axis did like the 1080p Bosch and provided day and night auto focus points. The IR corrected lenses I have do provide a better picture at night even without an IR illuminator on. Wonder if anyone makes a 950nm corrected 100mm lens...May end up with separate day and night cameras.

most of the IR I did in the past never used IR corrected lenses and worked just fine.

You just have to focus it off a tiny bit to allow for the focus shift, if not using IR lenses.

[Stanislav 0]

Axial IR intensity depends on consumed power and greatly depends on beam angle. For example, changing beam angle from 20 deg to 10 deg can increase max IR intencity up to 4 times, that increases max distance up to SQRT(4)= ~ 2 times. The same IR intensity of 850nm is in 2 times more effective than 950 nm, it increases max distance in SQRT(2)=1.4 times.

I'm building some IR devices, just to play around. Found some nice tight optics and the same IR units that Bosch uses in their newer units. Should be fun. The numbers above sounded maybe a little theoretical, it can be adjusted based on published numbers from Bosch Raytec etc.

 

Going to try to get there, but I want to do it with IP cams so we shall see. I'll report back after I get something built. Decided to lay out some circuit boards.

 

The only thing that nags at me is the HID unit, since if they can do a steep cut at 850 with no red glow as they claim then they might utilize the sensor a little better. Some of the plots I've seen show the CMOS is closer and 940 vs 850 than CCD. Time to see what can be done.

 

Yes This factor "4" is based on theory. In practice other factors influence on result too. Such as dependence between optic loss and beam angle (the less angle the more loss), repeated rereflection on the scene, which more visible with wide angles. These factors decrease influense of beam angle. Therefore I wrote "up to 2 times".

 

But the theory is good too. We compared modeling in VideoCAD with field tests of 7 different IR illuminators of different manufacturers and obtained very close results for 4 of 7. See the image.

 

 

Blue markers indicate modeled distances, red markers indicate measured distances in field. 4 illuminators from 7 were modeled very good.

If you are really interested see our discussion of these tests (in Russian!!) here you can find detailed description

[rory 0]

approx 20-30% loss at 850nm, approx 50% loss at 950nm, tested in the field.

[Stanislav 0]

approx 20-30% loss at 850nm, approx 50% loss at 950nm, tested in the field.

 

The difference depends of spectral response curve of image sensor and difference in reflection factor of the target.

My accurate laboratory test with special calibrated IR LEDs (image sensor=SONY ExView HAD, target= human body) shows what 950nm is 43% in efficiently relative to 850nm. With other image sensors the factor is in the limits of 40-50%

[ak357 0]

 

The difference depends of spectral response curve of image sensor and difference in reflection factor of the target.

My accurate laboratory test with special calibrated IR LEDs (imager sensor=SONY ExView HAD, target= human body) shows what 950nm is 43% in efficiently relative to 850nm. With other image sensors the factor is in the limits of 40-50%

 

Just curios

Did you use white level (IRE) of video signal as reference point ?

Can you share more info about testing procedure /

[Stanislav 0]

 

The difference depends of spectral response curve of image sensor and difference in reflection factor of the target.

My accurate laboratory test with special calibrated IR LEDs (imager sensor=SONY ExView HAD, target= human body) shows what 950nm is 43% in efficiently relative to 850nm. With other image sensors the factor is in the limits of 40-50%

 

Just curios

Did you use white level (IRE) of video signal as reference point ?

Can you share more info about testing procedure /

 

 

Equal bright of the same pixel of the image on the screen when illuminated by different calibrated LEDs was used as a reference point.

AGC was turned off.

The difference was calculated as a ratio between irradiances (watt/m2) of 850nm calibrated LED and 950 nm calibrated LED, when the same pixel on the screen had the same bright.

CCTVCAD Lab Toolkit was used to measure bright of the pixel.

 

Here are detailed descriptions of my testing procedures.

[rory 0]

approx 20-30% loss at 850nm, approx 50% loss at 950nm, tested in the field.

 

The difference depends of spectral response curve of image sensor and difference in reflection factor of the target.

My accurate laboratory test with special calibrated IR LEDs (image sensor=SONY ExView HAD, target= human body) shows what 950nm is 43% in efficiently relative to 850nm. With other image sensors the factor is in the limits of 40-50%

Well Im only letting you know field tested results, for 10 years.

[ak357 0]

 

The difference depends of spectral response curve of image sensor and difference in reflection factor of the target.

My accurate laboratory test with special calibrated IR LEDs (imager sensor=SONY ExView HAD, target= human body) shows what 950nm is 43% in efficiently relative to 850nm. With other image sensors the factor is in the limits of 40-50%

 

Just curios

Did you use white level (IRE) of video signal as reference point ?

Can you share more info about testing procedure /

 

 

Equal bright of the same pixel of the image on the screen when illuminated by different calibrated LEDs was used as a reference point.

AGC was turned off.

The difference was calculated as a ratio between irradiances (watt/m2) of 850nm calibrated LED and 950 nm calibrated LED, when the same pixel on the screen had the same bright.

CCTVCAD Lab Toolkit was used to measure bright of the pixel.

 

Here are detailed descriptions of my testing procedures.

 

Thanks

Spasibo drug

by the way

skolko tu xochesh za programu s ruskogovoryshim customeru

[Stanislav 0]

approx 20-30% loss at 850nm, approx 50% loss at 950nm, tested in the field.

 

The difference depends of spectral response curve of image sensor and difference in reflection factor of the target.

My accurate laboratory test with special calibrated IR LEDs (image sensor=SONY ExView HAD, target= human body) shows what 950nm is 43% in efficiently relative to 850nm. With other image sensors the factor is in the limits of 40-50%

Well Im only letting you know field tested results, for 10 years.

 

I am glad that concerning ratio 850/950nm our results are practically the same But concerning White light/IR there is a difference

 

 

Thanks

Spasibo drug

by the way

skolko tu xochesh za programu s ruskogovoryshim customeru

 

Thank you for your appreciation. Please contact me in case of any questions.

Cena odinakova v Rossii i za rubejom.

[skane 0]

Interesting idea, but I'm trying to be invisible to the jokers that come and take the GPS in the middle of the night. It's fine being visible as a deterrent, but when it comes to prosecution I'd like as little connection as possible. A month or two ago, two guys walked down the culdesac (pretty rare) since enclosed and tried the neighbors car doors. As they were coming across I think they saw my dome cams and left. Two other times I've seen people inside cars down at the end of the culdesac rummaging around. Classic situation people around here have too much money (2nd median income in the country) and don't lock the car doors. So people know where to come for an easy GPS.

 

They may have seen the IR units, but you have to know what they are. Anyway, just trying to be as invisible as possible to the neighbors, thieves and teen vandals...

 

I like the idea though.

 

If this is residential application and the punks are victimizing occupied properties, consider using outdoor motion detectors during the activity-timeframe, and catch them in the act.

[mike_va 0]

FWIW, just tested some osram 1A 940nm LED units (as it appears Bosch uses) and there is still a red glow...granted it is a lot less, but still.

[rory 0]

FWIW, just tested some osram 1A 940nm LED units (as it appears Bosch uses) and there is still a red glow...granted it is a lot less, but still.

I never used the Bosch 940nm LEDs,

I used the UF500 (not LEDs) made by Extreme CCTV at the time.

[Stanislav 0]

FWIW, just tested some osram 1A 940nm LED units (as it appears Bosch uses) and there is still a red glow...granted it is a lot less, but still.

 

Actually 850nm and 950nm IR are completely invisibly for human eye. The "red glow" is visible because of little side peak of radiation of IR LED within the visible range.

Thus, in theory, using special IR filters which cut visible range it would be possible to reduce the red glow. Such filters are used in photography, but they are expencive. There are filters of different density. I suppose the same filters are used in IR illuminators with incandescent lamp (like UF500).

Did anybody try such filters with IR LED illuminators?

[mike_va 0]

I tried some, to no avail. You're right, it's that side peak like I posted the data from. The magnalight uses a borosilicate filter, maybe this is what the old Bosch used?

[rory 0]

I tried some, to no avail. You're right, it's that side peak like I posted the data from. The magnalight uses a borosilicate filter, maybe this is what the old Bosch used?

That would explain the UF100 being invisible also, as it had a similar filter like from the UF500, in front of the LEDs as well.

[rory 0]

FWIW, just tested some osram 1A 940nm LED units (as it appears Bosch uses) and there is still a red glow...granted it is a lot less, but still.

 

Actually 850nm and 950nm IR are completely invisibly for human eye. The "red glow" is visible because of little side peak of radiation of IR LED within the visible range.

Thus, in theory, using special IR filters which cut visible range it would be possible to reduce the red glow. Such filters are used in photography, but they are expencive. There are filters of different density. I suppose the same filters are used in IR illuminators with incandescent lamp (like UF500).

Did anybody try such filters with IR LED illuminators?

now that I recall I did use the UF100 940nm .. that has LEDs I think . never opened it up.

But it also had the same type of filter over the front of it that the UF500 did

In fact all their IR lights use a similar filter, even the EX26 LED and the little EX12

[Stanislav 0]

I just checked UF100 spec. It has halogen bulbs, no LED.

 

There is another path in theory to make illuminator less visible - we should increase shining area. The more the shining area is the less brightness of the area when radiating the same power.

IR LED chips are small but irradiate high power.

[rory 0]

Ok maybe I as thinking about the EX26LED then, I have one here and it has the same type of red filter in front of it, but this one is 840nm so no way to tell.

 

BTW this illuminator is great, has power levels in a rear compartment, and easy to adjust. Just for smaller areas though, lights up my location great (plus I got it free, 2nd hand, new it did cost approx $400)

 

It runs off 12VDC also. I have the EX26LED, a TDN Bullet, and another 3 cameras on the same 2A power supply .. no issues

[mike_va 0]

Yes, the UF100 uses halogen and thus is probably a glass filter, due to the heat.

 

The Bosch units some at least use black perspex 962, which allows some red glow through.

 

Also tested some older Osram small 5mm black 940nm, which did not have a red glow. Maybe it was just distributed and less contribution from each. Did 9x to get a similar power to the 1A units. However, they also have slightly different curves so this makes sense.

[mike_va 0]

FWIW, just tested some osram 1A 940nm LED units (as it appears Bosch uses) and there is still a red glow...granted it is a lot less, but still.

 

Actually 850nm and 950nm IR are completely invisibly for human eye. The "red glow" is visible because of little side peak of radiation of IR LED within the visible range.

Thus, in theory, using special IR filters which cut visible range it would be possible to reduce the red glow. Such filters are used in photography, but they are expencive. There are filters of different density. I suppose the same filters are used in IR illuminators with incandescent lamp (like UF500).

Did anybody try such filters with IR LED illuminators?

now that I recall I did use the UF100 940nm .. that has LEDs I think . never opened it up.

But it also had the same type of filter over the front of it that the UF500 did

In fact all their IR lights use a similar filter, even the EX26 LED and the little EX12

[Stanislav 0]

The Bosch units some at least use black perspex 962, which allows some red glow through.

 

The Perspex 962 light transmission curve seems interesting. It transmits 90% in IR range and close visible range. Did you test it with 850nm and 940nm IR LED? It must decrease red glow, but practice experiment is needed.

You can use several layers to increase the filter effect. 6 layers will decrease 840 nm power in two times, thus it becomes like 940 nm in efficiency. It would be interesting to compare red glow between 840nm+6*Perspex 962 and 940nm clear with the same power consumption.

 

Also tested some older Osram small 5mm black 940nm, which did not have a red glow. Maybe it was just distributed and less contribution from each. Did 9x to get a similar power to the 1A units. However, they also have slightly different curves so this makes sense.

 

These curves don't cover visible range. The side peak in visible range is too small therefore it is invisible in the spectral distribution curves in real scale.

[rory 0]

..

LOL .. no need for a photo, i have the UF100 and 2 UF500 940nm's sitting in the garage .. just dont go in there much these days ..

[rory 0]

Since we are on this topic, I just got my hands on a KT&C TDN IR Bullet, Sony Effio Exview 700TVL, its the one with 20LEDs, the slightly cheaper model (still not cheap compared to others).

 

Anyway Didnt know it but was wondering why I could not see the LEDs ... well there was what looked like it might have been a very dim glow, so little It looked like they were not even on, and I could only see it if I was right up in front of it. No way anyone else would even notice those. Anyway, reading the manual turns out its what they call "invisible" and that would seem so, since compared to other IR bullets the IR in this case is barely 20' or so. Basically the camera itself sees like the CNB monalisa, sees in next to no light without IR so it works out okay anyway, with the dusk to dawn light on its in full color - basically if you want an IR bullet stay clear of this, its useless for that. Otherwise it will work fine where I need it, there are all kinds of street lights.

 

Maybe the 45LED model is better for IR .. costs $50-70 more though and the client decided he didnt need it.

 

In addition to that camera I have an $89 IR bullet branded by 123, its a color IR with 4-9mm and 600TVL. My dusk to dawn kills it, unlike the KT&C which handles it just fine. But this camera has alot of IR for a cheap camera, sees out to at least 50-60 feet in total pitch dark. Its going in the narrow back of a building and there wont be light, so it works out well.

[rory 0]

this shows the IR beam only ..

 

600TVL 2.8-11mm Color IR dome

Very visible IRs ...

 

 

700TVL KT&C with next to invisible IR

They dont say what wavelength it is

 

 

 

This is the $89 Color IR Bullet

outside of the IR beam it is nothing but noise ..