Is ICR = IRCut?

[Kurt 0]

I notice that some manufactors state that their cam has IRC, or Auto ICR.

Do they mean the same as IRCut, a mechanical IR filter?

What does ICR stands for then; Infra Cut Red

ICR also seems to be a brand name?

 

So an IRcut filter is also responsable for a focus shift, Is a IR adjusted lens always the way to go in this combination?

How to tell a lens is IR adjusted? I've never have seen it in the spec's.

[David Yu 0]

Dear Kurt,

 

Glad to make a friend with you! This is David

 

IR Cut use the double filter to suit the D&N requirement.

IR Camera will loose the natural color, it is the shortage of the IR Camera; and B&W camera can get the natural color in the day , but it can not see in the low illumination condition. In the day the common filter to cut the infrared light and get the natural color. While the illumination is lower enough, it will turn to the other filter(ICF), it can cut most of the visible light and change to the B&W situation to support the totally night-see function. So it can get the pure and natural color in the day and more clear in the night.

 

ICR is the same meaning, but professional express way is IR Cut.

 

If you have any promble ,PLs let me know . Hope I can answer it for you.

[rory 0]

Infrared Cut Filter is simple .. without it a Day Night Camera will pick up IR in the day time also .. such as from the Sunlight .. that way the colors will be all off, or in some cases florescent like. The IR Cut Filter goes over the chip in the day time and blocks out the IR. In the nightime the camera removes the IR Cut filter and it once again can pick up IR.

 

Most color only cameras will have a fixed IR Cut Filter, while BW Cameras should not have one at all.

 

Yes as far as I know IRC is just shorthand for Infrared Cut Filter. Best to check the camera specs though to make sure it mentions a mechanical IR Cut Filter.

 

As for IR Optimized lenses, they should say that on the lens itself. However from the previous cameras I just tested, even those still have some minimal focus shift and focusing under low light conditions were still the optiomal solution, in fact I found focusing under controlled lighting is the best as you can then focus in low light and make sure it is staying in focus in full light as well as in pitch dark with IR on, and ajust as needed.

[atropine 0]

 

Most color only cameras will have a fixed IR Cut Filter, while BW Cameras should not have one at all.

 

 

My B&W box cameras all have IR filters on the CCD. They are old though and meant for use in the same situations as colour cameras. So you would need to filter out the infrared light to gain a sharp picture (assuming non IR lens).

 

Maybe B&W box cameras sold today are sold for the expressed use of low light, not general purpose so come without the filter.

[rory 0]

My B&W box cameras all have IR filters on the CCD. They are old though and meant for use in the same situations as colour cameras. So you would need to filter out the infrared light to gain a sharp picture (assuming non IR lens).

 

Maybe B&W box cameras sold today are sold for the expressed use of low light, not general purpose so come without the filter.

 

Not that many BW cameas being sold these days anymore, but yes more customers seem to be interested in IR now so I imagine that is why. I havent come across a BW camera though in the past several years that had an IR Cut Filter, but it could depend on the brand and model ofcourse.

 

How old are the ones you have, and whats the brand?

[CameraGimp 0]

 

My B&W box cameras all have IR filters on the CCD. They are old though and meant for use in the same situations as colour cameras. So you would need to filter out the infrared light to gain a sharp picture (assuming non IR lens).

 

Maybe B&W box cameras sold today are sold for the expressed use of low light, not general purpose so come without the filter.

 

An Ir cut filter on a monochrome would give a true greyscale not improve resolution.

 

In the same way IR skews colours it will also skew luminance. it's just we like it to do this in low light surveillance applications. Imagine you look at a person wearing black cotton pants and a black fleece jacket with a colour camera you will see black pants and and equally black jacket.

 

But if you look at the man with an IR sensitive mono he will have black pants and grey jacket because fleece reflects IR and so doesn't appear black. So an IR filter won't alter resolution or sharpness but it will make sure things look true to life.

[atropine 0]

Yeah I understand what you're saying CameraGimp.

 

Rory, these are all Chubb B&W cameras, standard and high resolution 1/3" CCD. Made in Portual of all places. They only go down to about 0.2 lux and do not have any DSP, so the AGC noise (when turned on) is completely useless with motion activated recorders at night, which indicates how old they must be.

[Kurt 0]

Intresting stuff,

Cameragimp, I'm a right to say when an IRfilter is used on a B/W camera that then this camera will be a little less sensitive due the filter in front of the CCD? So you have better grayscale but have to give up a little sensitivity?

 

I had a look at 2 of my box Colour cam's; when you unscrew the lens, should you see the IRcut filter/mechanisme straight away?

I don't see anything removable dough, maybe a fixed IR filter I'm not sure.

Have a look at the pic's. (strange they don't come through, first I had this message for new users, but now, not anymore but still don't work?!? Pls. follow the link. What am I doing wrong?

first pic:

and the second;

 

Oh, yes, ICR should stand for Ir Cut Removable.

Mostly those Tawain & Korean manufactors make a mess of their discriptions of the camera's. My guess is to look for 'True IRcut' to find a cam with mech. IRcut. But sometimes you see Day/Night, IRcut, ICR,....

[CameraGimp 0]

Hi Kurt,

 

I'd say a monochrome camera with an IR cut filter will be quite a bit less sensitive than one without. It would be about as sensitive as a similar colour camera. I worked for a camera manufacturer for 12 years and in that time we never once made a monochrome camera with an IR cut filter and I can only remember coming across one camera by another manufacturer with an IR cut filter. That was a Phillips or Bosch Dinion and that was weird at the time.

 

It makes no sense to do it unless there was some machine vision / footfall application that needed the resolution of a mono as far as I could figure.

 

Ten years ago people bought monochrome cameras for one of two reasons, they were cheaper (this is back in the day that you could buy monochrome multiplexers) or they wanted the low light performance.

 

Nowadays colour cameras are cheap and you don't get mono muxes so you only need a monochrome for sensitivity or resolution but most end users don't look at a monochrome image and say "hey thats got great resolution" do they. Kind of makes you realise that 520tvl colour cameras might be more marketing led than end user led. Anyways..

 

It isn't easy to see from the pictures you've linked to but an IR cut filter is a piece of cyan glass (actually a crystal). It should be sat in front of the CCD. It looks like it is there because I can see the green/blue tint.

 

If you had a true day/night camera there would be some kind of mechanical device that would slide the piece of glass out of the way. They should replace the filter with another piece of glass of identical optical characteristics (so you don't need to adjust the back focus). Only this piece of glass doesn't have the IR cut part and passes IR.

[rory 0]

good info CameraGimp, also something to note that on a couple Day Night bullets and one Day Night dome I recently dissected the Mechanical IR Cut filter was part of the lens, it sits between the focus and the zoom, and to get to it you remove the zoom (dont do it less you have time and patience and dont mind rendering the camera useless if you loose the tiny screws and have no spares ). Least it was on the CNB, Eclipse, Sanyo, and as far as I can tell (though I didn't not disect that completely) the Nuvico.

[vin2install 0]

ICR (Infrared Cut-Filter Removal) works in two ways. On box cameras the the filter sits in front of the CCD module. The filter is rectangular in shape and is split into two parts. One side is IR sensitive the other blocks out IR to achieve the correct colors. It is powered by magnets to switch it on or off. When there is an electric field it will slide the correct side over. This is controlled by the separate ICR chip. The chip is activated by an external CDS sensor. So when it gets dark then the ICR is activated. Its kinda like the ones that turn on the LED's. I work for a camera manufacturer and i repair these all day. These are the first things that go bad on day/night cameras. I'm guessing because of the mechanical nature of the ICR.

[atropine 0]

Here's an example of the infra red filter moving into place. I quickly recorded this with my phone cam, so not focussed perfectly.

 

Edited May 2, 2008 by Guest

[Kurt 0]

That helped me a lot.

Now I'm sure I have no mech. IRcut filter on my box cam's.

Originally I thought I had, because they change to B/W at night and especialy the Philips Dinion gives a good image.

Rory, any change you have a picture of these lenses with build mech. IRcut filter?

I can't image how it can work? Where does it get it signal & power from to operate? Are these removable mini board lenses?

I noticed some True D/N tubes & domes in the Tracer range, I think they will be using this lens also.

 

I made another picture: I think the left one (Tracer TS730EH) is using a IR pass filter and the right one (Philips Dinion LTC0455) is using an IRcut filter.

These 2 models don't have a mech IRcut filter. But is a TRUE D/N cam with mech. IRcut filter using an IRcut filter at one side and a IR pass filter at the other side of the sliding filter holder?

[Securame 0]

It isn't easy to see from the pictures you've linked to but an IR cut filter is a piece of cyan glass (actually a crystal). It should be sat in front of the CCD. It looks like it is there because I can see the green/blue tint.

 

ICR (Infrared Cut-Filter Removal) works in two ways. On box cameras the the filter sits in front of the CCD module. The filter is rectangular in shape and is split into two parts. One side is IR sensitive the other blocks out IR to achieve the correct colors. It is powered by magnets to switch it on or off. When there is an electric field it will slide the correct side over. This is controlled by the separate ICR chip. The chip is activated by an external CDS sensor. So when it gets dark then the ICR is activated. Its kinda like the ones that turn on the LED's. I work for a camera manufacturer and i repair these all day. These are the first things that go bad on day/night cameras. I'm guessing because of the mechanical nature of the ICR.

 

Old thread, but thanks a lot on this info!