Hi CCTV Forum,

I work for a company that is interested in getting accurate counts of the number of people entering a exiting bars and clubs throughout the evening. I'm sure a number of users on here have used tracking cameras and software. Through testing we have found that most cameras that work in low light situations don't track all that well overall. The cameras that track best (95%+ accuracy) are pretty worthless in low light situations. By far the best camera we have found is the 3D camera found here: http://goo.gl/ozuPj. The 3D camera allows the tracking software to calculate height, so things like shadows and drapes, that would normally "trick" a conventional camera are a non-factor. Unfortunately, the camera doesn't work at all in conditions under about 6 lux, which is maybe half the environments we are targeting for installs.

What we would like to do is explore the possibility of taking this camera off the shelf and converting it into a camera that is able to detect IR light. Then, we can flood the viewing area in IR light and have this track in low light. In December we gutted one of these cameras and replaced the IR blocking filters and replaced them with IR filters that allow IR light to pass. Some pictures of the camera and innards are attached. We were able to see IR light, but couldn't get the lens focused very well. I think that we could make this camera a low light camera if the right person can play around with it. Does anyone here think they might be able to tweak this camera to make it work with IR light? Does you know anyone that might be able to help us with this project?

Sorry if any of this is unclear. If you have questions I will answer them as best I can.

If you know of any low light cameras that track well that would also be helpful.

Thanks!

According to the link you provided, the camera is B&W:

This probably means there is no IR cut filter (or the filter is removable under software control). Add some IR illuminators and you should be good to go.

There is an IR filter (that blocks IR light) in the camera by default. I bought two IR filters (that allow IR filter to pass) and swapped them in for the factory filters. I used the BP850-R14 filters (specific details found here http://www.machinevisionfilters.com/bp850.html). Once I booted the camera back up the scene was extremely blurry. The lenses on this camera are calibrated and cemented in the factory. I made a little tool to allow me to adjust the lenses, but I had trouble getting the focus correct. Not to mention that getting both lenses calibrated so that height could be properly calculated was nearly impossible to do by hand.

The replacement filters are 2mm thick and the default filters were 1mm thick, which might have been part of the reason I was having so much trouble getting the camera focused. I think what I need to get this to work is someone with a mechanical device that can adjust and calibrate the camera using mechanical means (it's just too tough by hand)

Have you considered using a thermal camera? At least the image would be consistent day and night making it a lot easier to calibrate for people counting. I've never tried this but it's just a thought.

Colin B
http://www.zeecure.com

Yes, we have considered using thermal cameras. In fact, we have tested three different thermal cameras, but they are generally very expensive and are subject to the many of the same issues as a non-3D optical camera as well as a some unique ones. We have seen issues like "heat shadows", blasts of wind when it is either very warm or cold outside, people bundled in winter clothing, hot food, or cold drinks throwing off thermal cameras.

I guess what I'm really asking is if anyone is (or knows someone who is) an optics expert and would be able to take a look at the camera to see what they could do to make this work as an IR cam (i.e. putting in a filter that permits IR light to pass and calibrate both lenses).

I appreciate all the feedback from everyone on the forum though!

Nice to know about the analytics on thermal, I wouldn't have thought about that but it makes sense.

Where about are you located? I know a couple places near me (Toronto area) that might be able to help but you would need to take it in to them because I don't have any personal relationship with these camera repair shops.

Colin B
http://www.zeecure.com

I'm in Chicago, but would be willing to ship the camera to another location for them to take a look. I have contacted a few different camera shops (that either do SLR IR conversions in house or ship them to a third party) but didn't get very far with those conversations. If you have some names, emails, or phone numbers you could pass along that would be much appreciated! You can send me a personal message with that information if you don't want that floating around the interwebs too.

Thanks!

Sounds to me like you've really exhausted every resource, at least beyond what I can think of. The only people I know local to me that might be willing to take a look at it is http://www.nortownphoto.com Don't be thrown by the simple website they really know their stuff when it comes to imaging technology. It's a long shot but they are privately owned so they may be a bit more helpful or at least be able to refer you to someone who can help. The other guy I know has told me this is too complicated for him, and he's probably right. Sorry I can't be of more help.

Colin B
http://www.zeecure.com

Thanks for making a few calls to help out Colin. I'll contact Nortown Photo to see what they have to say. Hopefully I can come back in a week or two with an update saying we got everything working!