IR Camera Reflection Test

By Ethan Ace, Published Oct 17, 2016, 09:26am EDT

All that might stand between good video and bad in your IR dome is a ring of foam rubber, keeping infrared from reflecting into the lens. Installers may have seen this small part on any number of cameras,

The gif below shows removing and replacing this part on a Hikvision minidome:

But what does this seemingly minor component do? How much effect could it really have? We answer these questions in this report.

Small ****/**** **********

** *****, ******* **** piece ** *****, ***** are *** *** *********** problems:

  • **********:********** ** ******** ******** back **** *** ****, obscuring *********** *** ****** view ** *** ****** and ******* *** ****/**** reflected **** **** *** dome.
  • **** ******** **********: *** camera ******** ** ****** exposure ** ********** *** the ****** ***********, ******** visibility, ** ** ** the ******* *****, ****** eliminating ********** ** **** of *** *****.

With **** ** *****

**** *** **** ** place (** ******), *** subject ** ******* ******* in *** ****** ** the *****, ******** ******* properly, *** *** ***** is **** ****** ***********.

Out ** *****

******** **** ***** **** simply ******** *** ***** as ***** ** *** gif *****.

** **** *******, *** subject ****** ** ~**' from *** ******, *** can't ** **** ***** he ** ~*-*' ****. Even ** **** ********, few ******* *** ********* through *** ****/**** ********* on *** ****** ** the ****.

Practical *******

**** **** ******* ** nor ************* ********* ****** or ******** ***** ******** found ** ** *******. This **** ** ******** simply ** **** *** net ******* **** *****.

*******, ***** *** *** practical ********* ***** **** may ** ***** ******* in ****:

  1. ***-******* *****/********:** **** *****, ***** foam ********** *** *** out ** ****** ******* during *******, ******** ************* and ******** ** ** leak **** ** *** lens. ************* ** ********* the **** *** ****** or ****** ***** ******.
  2. ***** *******:**** ***** ** ***** did *** ******* ******** such ** *****, ** included **** ********* ***** of ********* *** **** from ************. **** *** a ****** ********* ** earlier ** *****, *** less ********** ** ******* models. ***** **** ******* experiencing ***** ****** ***** consider ****** **** ******** between **** *** *********** as * **** ****** (such ** **** ****** cut ** **** ** even *********).

Other *******

*** ** *** ** dome ******* ** *** tests ******** **** **** of ******** ******** ******* the **** *** ** illuminators. ** ****, ** is * **** ****** ring ******* ** *** one ***** ****. ** others, ** ** ****** or *******. **** ******* do *** ***** **** component ** ** *******/********.

**** ******** *** ***** here:

Comments (12)

That's clear, but, another problem in dome cameras, is reflection from dusty dome outside surface. And, when we clean this surface, after some time scratches appears on surface, and reflection effect becomes permanent....

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We never use IR dome style cameras outside anymore because of this. Our high salt tropical atmosphere starts degrading the image from day one. Turret style with separately located IR led and Lens are way more effective. If the really high end smart features are required we use a discrete IR device ( and charge for it!)

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https://ipvm.com/forums/video-surveillance/topics/ir-shield-technology-clinton-claims-to-overcome-rain-or-dust

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Another, appearing at any camera with integrated IR (even, when separated glasses are used for camera and IR) issue:

Also, big problem appears at high snow.

Separate IR lighting, placed at about 0.5m below camera - more times better solution, if you want good night time image.

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That rubber ring on the Axis P3225 is a bit of an annoyance, because it's so stiff, if you don't put the dome on exactly straight, it can push the camera's aim out of place.

One other thing I've noticed with some cameras is, over time, the gasket itself can leave a permanent mark on the bubble, which can then affect the image if you ever have to re-align/re-aim the camera.

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I have switched to turret and bullet after contending with all the issues with domes that you guys have mentioned.

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I've also used turret a lot to deal with this.

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Even with this ring though, you can still get some IR reflection from the light going sideways thru the glass and then bouncing off of dust or moisture on the surface.

Older bullet cameras used to have a similar ring to these domes, but now are usually thru-the-glass rings for this reason:

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We had at a period a big problem of IR reflection with dividers. The supplier has solved the problem by changing the plastic cover by another one which had been treated to herden the plastic (I don't know exactly how...). It's the supplier of the plastic dome that has done this special treatment.

And the result was good.

To avoid this problem, I prefer to use "ball cameras, like this model:

Ball camera

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Note to all, based on findings from this test and reader comments, we plan to do some testing of dust/dirt/scratch impact on IR image quality to show those specific effects.

I believe we also have a test on IR cameras in snow which I can't honestly remember the title of... but I have images from it, and yes, integrated IR when snowing obscures a lot of the FOV:

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I believe we also have a test on IR cameras in the snow...

Yes, there was a report from Jan 28, 2015 called

Testing Integrated IR Cameras In Snow

it started like

'Snowmaggedon 2015' gave us an oppportunity to test cameras in heavy snow conditions.

Integrated IR has gained in popularity, improving low light images even in low cost cameras. However, is it right in all conditions? Can these cameras' integrated illuminators actually reduce visibility under some conditions?

Cameras were tested in this FOV, shown here during the day. Outdoor lighting at night is dim, about 0.5-0.8 lux.

We tested IR bullets during heavy snow to see what impact, if any, IR illumination had on visibility, motion recording, and bandwidth.

But it is currently not found thru search.

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That's the one. Odd that it's disappeared. We'll remedy that.

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