help required evaluating Axis 221 day/night camera at night

[jwexqm 0]

I'm currently investigating the use of IP-based cameras for a project. I'm also venturing into night time surveillance for the first time.

 

I have an Axis 221 day & night camera on evaluation. I wanted to compare it with some other camera in the same conditions. So as a reference I also tested a very generic budget analogue 1/3" sony CCD external day/night camera. This camera doesn't have the mechanical IR cut filter that the Axis 221 has and presumably achieves its night mode completely through electronic processing. The generic camera has a ring of 20 or so IR leds around its lens although these didn't really reach even a third of the way down the driveway test site. I fed the video out of this camera into a composite input on an ATi graphics card and grabbed at 720x576.

 

I used a Derwent covert IR MFLED with 20 degree beam to illuminate the driveway. There was some overspill visible light on the scene from nearby windows, but other than that, the scene was in darkness.

 

Here are some test grabs from captured video...

Axis close subject

Video close subject

Axis distant subject

Video distant subject

 

I might be wrong here, but from my limited testing I feel that there are issues with doing night time surveillance using a night time IR sensitive camera...

- hyper sensitivity to IR light levels (camera easily bleaches subjects if too much IR light is reflected back at the camera)

- any visibile light source (headlight, torch, security light) tends to have a dramatic bleaching effect on the picture.

- lots of grain on the picture

- long exposure times reduce frame rate to <10 FPS so blur makes face ID difficult

 

I tried tweaking all of the settings on the Axis' web interface but just didn't really get away from the above issues.

 

I'm just left with the feeling that if I'm to do this installation with covert IR and the camera in night mode then I'm going to need a lot of low intensity IR light sources bathing the area rather than relying on a spot. Maybe the other option is to push the client into visible light illumination and ditch the IR altogether.

 

I actually felt like the cheap analogue camera (which is completely automatic) adapted to varying lighting conditions a little better than the Axis. Sure, it wasn't as sensitive to the IR flood light as the Axis was in night mode, but it still made a difference and the bleaching problem wasn't there at all. Plus the cheap camera 'made the best' of any additional available visible light sources rather than the more 'precious' Axis that would just bleach out.

 

The axis camera station software gives you the option of doing motion detection on the camera or in the camera station application that runs on the PC. Doing motion detection on the PC is just like Geovision, wastes network bandwidth and feels like a step backwards. For this reason I tested using the camera's motion detection facility. I found that the recordings I made using camera station usually had missing frames (particularly at the beginning) and I felt that the the pre-motion-buffer function didn't work as well as I've seen with Geovision. I suspect though that this might be to do with the amount of buffer RAM the camera has on-board.

 

To be honest I was expecting better from the Axis, but I don't know how fair that expectation is. My client was excited about the Axis' progressive scan CCD feature. At night though, progressive scan doesn't really seem to make much difference because the long exposure blurring problem dominates. In the day though it's definitely a nice feature. The 640x480 0.3 megapixel CCD in the Axis feels a bit low too, particularly with those IQinvision >1MP cameras surfacing now.

 

The Axis build quality is very impressive though and the convenience of IP-based video is super attractive. Manual zoom control also makes setting up each camera location much more flexible. I'm fairly sure the Axis 225FD (fixed dome) is almost a 221 in weatherproof dome clothing which could be a good option for where a 221 in weatherproof housing would be too big and chunky.

 

I'm not entirely convinced by the camera station software though, particularly considering it's licensing model and cost. I know Geovision looks like they had the crack pipe on the go when it was being written but it does actually do quite a bit, so I've got that in the back of mind when I'm playing with camera station.

 

So based upon the above, I'm looking for some guidance, either in terms of things I could try to improve the results with the 221 or to fix some element of my knowledge about night time surveillance. I'd be grateful to hear anyone's opinions.

 

James

[Securitymaster 0]

Uhm, what kind of genetic camera are you using?

[rory 0]

Hi, and welcome to the forum.

 

Dont judge IR by the cameras used in this example .. not all cameras are made alike. What was the other camera, brand name and specs? Axis is not considered a high end camera for Infrared Applications either.

 

There are 2 different applications

 

1-Day Night

2-Infrared Day Night

 

Visible light will always be better than using Infrared.

 

IR Sensitive is not the same as IR Optimized (or IR Corrected).

Day Night doesn't mean it is IR Optimized (or IR Corrected).

 

Typical Day Night is easy to achieve, once there is sufficient light and the right camera and lens is used. The Digital day nights do not compare to the True Day Nights which use Mechanical Filters to Switchover between Color and BW, though there is some new technology coming out now.

 

Sensitivity to Infrared greatly depends on the camera. The Color IR camera you used in the example above appears to be a generic OEM box camera with a lens that has some IRs on it, its not considered A Day Night camera, merely a Color IR camera, has no physical switchover to BW mode. Therefore as it has no IR pass filters it will not be as sensitive to IR and especially the higher IR wavelengths, and without IR Cut Filters the day time image will be slightly washed out due to the IR produced from the sunlight.

 

The IR Bleed effect and the glare also depends on which camera is used, and also, what lens is used. Extreme CCTV designs their cameras specifically for Infrared Applications, so they would be an example of a professional IR camera. Using an IR corrected lens also gets rid of most of the focus shift issues between Day, Low Light, Night, and Night with IR. A few years back those lenses didnt exist and i had to use regular lenses, they worked okay, but would go slightly out of focus at times.

 

Now it is easier, but those IR Corrected lenses arent cheap. Still, even with IR Optimized cameras and IR corrected Lenses, nothing beats a seperate color camera for day time, and BW for night time, especially when dealing with IR, but even in normal Day night apps, at night time the standard BW camera and a single color camera for daytime will outperform a single Day Night camera.

 

Now, that said, Ive used Sanyo Day Night box cams and they came out great for IR apps, though not as good as I would have liked. Would i use them again for IR apps, no, Ill just make the client spend he extra couple hundred $$ for an easier job and better IR image. Though at 1/3 the cost of the Extreme IR cams and basic home application it was fine. It takes alot of time from the design to the installation, so honestly in the long run, its better and cheaper sometimes to just buy something like the Extreme CCTV All in one IR cameras, or the All in one Day Night IR optimized cameras, then add the IR that is required. (no housings, no IR bleed, etc).

 

As for the glare, ive come across that myself, its basically that you have to choose the IR for the location. Unfortunately even with the short range IRs like the one you used, if it is too close to the subject it will produce glare on their face and you wont be able to make them out. Moving it up higher, pointed upwards more, or mounted off to the side can help.

 

Each IR from Derwent (same as Extreme) have different beams, lenses, and power options and settings. You can drop the Infrared Output from the greatest distance of IR - either by using the IR level adjuster (only on a couple of them however), by using higher IR wavelengths (requires a IR sensitive camera that specs the actual IR response in nanometers), or on the power supplies tapping the output from the transformer down so the bulb gets less power. Each of these can drop it by 20% approx, or more, depending on the IR illuminator used.

 

Hope this helps some ..

 

Rory

Edited January 15, 2006 by Guest

[Securitymaster 0]

Rory, I say time after time and again and again.

 

You have too much time in your hands dude.

[nextan 0]

Check out the ACTi's answer to AXIS 221, the CAM-5120:

 

http://www.acti.com/Web_AdministratorV2/CatalogV2/DataSheet/{03C40ECE-27CA-4085-9022-76A2FBE70D4.PDF

 

The ExView CCD used by CAM-5120 has better low light performance than the WFine CCD used by the AXIS 221.

 

ACTi also has a better MPEG4 codec than the AXIS, with 30 fps capability at full D1 (720x480) compares to AXIS 24 fps at VGA (640 x 480).

 

Price wise, ACTi is at least 30% cheaper.

[jwexqm 0]

thanks for the replies - particularly Rory - a real wealth of info there.

 

the video camera is unbranded - cost £90. All I know is that it's apparently got a sony 1/3" CCD. I have a picture of it.

 

[rory 0]

no problem, dont expect much from that camera, its a cheap one, Sony makes so many different grades of CCDs from low to high end.

 

I rate those type of cameras as more of a DIY camera. Especailly as its a bullet camera, the ones i was talking about were Box cameras, which are much better than bullets for quality and performance, and yep, they cost 4 times as much.

[JMANOFNVS 0]

Why not try an extreme cam and run it into a video server?? It would be about the sam price as that axis cam. What are you trying to accomplish anyways.