Thermal Imaging Camera with a difference ! It may be watching you  - Page 1
Forum section: electronics / general

author: Fraser
author_rank: Super Contributor
timestamp: March 17, 2013, 12:35:41 pm
content: I recently won a very neat thermal imaging camera for GBP6 + GBP6 postage on e*ayThe reason it was so cheap? I doubt most people would have known that it was a TIC as it looks like a common smoke detector. The giveaway was the Germanium lens in the centre of the unit, and the fact that I had tested such a unit some years ago so I recognised it.The seller had no idea what its true value was. The unit is made in the UK so I contacted the manufacturer, who is only 10 miles from where I live....it gets even better....the support manager has provided me with all the documentation and engineering software to view the thermal camera output (Raw thermal images) on a PC screen.The history behind the unit is a little sad. The unit came from a chain of UK stores that have gone bust recently It is a high-tech people counter and tracking system that is commonly used in shops to count footfall on the premises and to analyse shopping behaviour. TESCO use them extensively for real time data collection.One chap on the internet even managed to use one to establish whether you are a male or female shopper by using the different walking gates ! The unit can see your lateral movement. I think girls ‘wiggle more’. They certainly do when viewed from behind !This COTS product is capable of logging multiple targets and their movement patterns, linear, meander, circling or stationary! A classic retail use is to detect shopper behaviour around display stands to ascertain the effectiveness of the sales technique. Lots of shoppers congregating or circling the stand is good. The TESCO queue management system uses them to automatically warn floor managers that the checkout queues have more than ‘X’ people in them, and so more checkouts can be opened. This unit is exempt from the CCTV rules on capturing public data as it does not capture faces or identifications of the targets. The old techniques used CCTV and had issues with holding images of the general public.The whole unit is the size of a common smoke detector and it contains the TIC, DSP, embedded computer and software for multiple target acquisition and reporting ! Humans are identified by the shape they present to the TIC when viewed from above. Each target is allocated a number and tracked whilst it is in view. Many targets can be simultaneously tracked and a bread crumb trail is logged for show tracking behaviour.A really neat piece of technology that cost a small fortune when new, mine for less than GBP13. It really is worth keeping an eye on e*ay sometimes.The TIC auction was here:http://www.ebay.co.uk/itm/271158452825?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649I am only interested in the raw TIC images that the unit provides as I have no use for people tracking in the domestic environment.Fraser

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 17, 2013, 01:10:44 pm
content: 1-off end-user price on these is around £750.They are only marginally useable as a TIC as they are unshuttered, and only pick up temp differences. Irisys did make a handheld TIC with the same sensor with a motorised shutter (IRI1011), but the 16x16 resolution makes it very hard to use as it's difficult to tell what you are actually looking at - I wouldn't reccommend it, even for cheap!I designedThis productaround it, adding an internal processor board to decode their datastream into something more meaningful.FYI this is what the sensor looks like :

author: Fraser
author_rank: Super Contributor
timestamp: March 17, 2013, 01:33:45 pm
content: Hi Mike,Thanks for this. I was going to buy your Irisys unit when you sold it but the bidding went out of my range. As you say, a 256pixel sensor, even when cleverly interpolated is the major limitation. I have my Argus 1 & 2 plus the Agema 570 for quality images but I couldn't resist the opportunity to play with this low resolution Irisys technology. What Irisys have achieved with the sensor is impressive. They also use intercell thermal leakage to determine whether a heat source is in the middle of a cell or towards the edge. Very clever as this effectively increases the resolution in some applications, like the people tracking.My BST based TIC's use a shutter wheel so I am familiar with the need in a staring array but a panning array creates it own thermal change at the sensor. I am not ceratain whether I can run a non synchronised shutter wheel or whether I will have to make the TIC physically scan a scene to create change. I must say Irisys were very helpful and mentioned the need for a shutter of some description. As it stands its would make one hell of an intruder detector !The detailed product Patents, plus the University thesis on identifying gender were also very usefull sources of inforamtion on the technology used. Your project using these units looks excellent as well !I have a lovely AGEMA Thermovision 800 series industrial TIC that uses a scanner system and 1 pixel thermal sensor. Sadly it requires Liquid Nitrogen though. I would love to fit the Irisys uncooled sensor into it, but I believe that will be beyond my skills.I am envious of your FLIR=Fire unit !Many ThanksFraser

author: Marco
author_rank: Super Contributor
timestamp: March 17, 2013, 01:50:06 pm
content: Quote from: mikeselectricstuff on March 17, 2013, 01:10:44 pmWhat is the difference between a temp difference and absolute temperature sensor? Black pixels and processing?

author: Fraser
author_rank: Super Contributor
timestamp: March 17, 2013, 02:09:17 pm
content: From memory a sensor such as the BST or Pyroelectric vidicon only output changes in cell/surface state, wheras a sensor like the Microbolometer used in modern TIC's presents a change of resistance in the cell, calibrated to give absolute temperature. From memory the BST sensor is much like a capacitor, it will equalise its charge if no change is introduced to it and so no p.d. is present to 'read'. On an unshuttered BST or PyroVidicon TIC, a static heat source will be shown brightly as it comes into view, but if the TIC or target does not move, the charge in the sensor equalises and the heat source just blends into the back ground.In the case of a BST or Pyrovidicon TIC, a shutter wheel is used to create regular change in the sensors view. For the Irisys people counter/tracker the lack of a shutter wheel is actually deliberate so as to remove spurious static heat sources from the view, such as radiators etc. People move and generate the required change at the sensor. Clever thinking.Fraser

author: nctnico
author_rank: Super Contributor
timestamp: March 21, 2013, 02:10:09 am
content: Quote from: mikeselectricstuff on March 17, 2013, 01:10:44 pmWhat do the sensors cost and where can you get them?

author: Neilm
author_rank: Super Contributor
timestamp: March 21, 2013, 06:59:17 pm
content: Quote from: Aurora on March 17, 2013, 12:35:41 pmYou can also check the front thermal image - girls have a couple of warmer areas in the chest region.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 21, 2013, 07:06:14 pm
content: There are some sensors avaialble that are getting fairly close, all around the GBP£30 mark - Panasonic do an 8x8 sensor (which the bastards at Digikey won't ship to the UK!), Omron have 4x4 and 1x8 (with 16x16 promised) , plus the Melexis 16x4 used in IR-Blue

author: nctnico
author_rank: Super Contributor
timestamp: March 21, 2013, 10:21:45 pm
content: OK, that is interesting. I'm currently working on a project which is about detecting people in places where they shouldn't be.

author: Fraser
author_rank: Super Contributor
timestamp: March 21, 2013, 10:55:35 pm
content: Interesting usageFraser