2010 marked the centenary of the first published infrared image. This is the Infrared 100 blog, which celebrates that centenary and discusses all aspects of infrared imaging: near and far.
The Guardian recently published a photo set matching far infrared images of Phoenix with ordinary photographs.
The images were taken by Carlos Barria, using a Flir thermal camera, which also shows a point temperature (in Fahrenheit).
It's an interesting set, taken in late July 2023 and which "reveal a Phoenix where concrete on the street registers 150F (66C), outdoor workers’ bodies reach 105F (41C) and homeless people swelter, surrounded by surfaces as hot as 143F (62C)" and it's unusual to see visual and thermal images matched in this way: you can swipe between the two.
Back in 2011 I noted some IR shots of outer planets by Mike Brown at Caltech, at a wavelength of 1.5 µm.
Last week another fascinating set of images, this time of Jupiter, emerged. These were at 4.7 µm and rather than a demonic cricket ball this time the infrared image resembled a jack-o'lantern.
This wavelength reveals a glow from relatively warm deeper layers of the atmosphere breaking through upper cloud layers. In visible light this is obscured by even higher haze in the atmosphere. The image here is a composite built from a number of so-called 'lucky' images, captured from earth during brief pauses in our atmospheric turbulence. The instrument was the Gemini North telescope on Hawaii’s Maunakea volcano, at an altitude a little over 4,200 metres.
I was somewhat surprised to see that discount supermarket Aldi's latest catalogue includes a thermal imaging camera. It's probably more expensive than anything else they sell, at £899, but to be honest that's not a bad price for a 320 by 240 resolution camera of this type. The cheapest near equivalent I could quickly track down cost over £2,000. To be honest, if what you want is either to track heat leakage on a building, a hot spot in a circuit or find an animal in the dark then this should be fine. 320 by 240 is even a reasonable resolution for some artistic thermal imaging. Of course going for 640 by 480 or even more will set you back well over £10K, so 320 by 240 is almost hi-res for a thermal device.
The make is Rothenberger who, amongst other things, produce a wide range of imaging/inspection products. The company was founded in Germany in 1949.
You won't see these in store however ... it's an online special only.
For comparison, the current FLIR One camera, which now clocks in at 160 by 120 sells for around £400 and works with your mobile phone.
Having produced some highly successful images using medium-format false-colour infrared film, Richard Mosse turned his hand to thermal imaging. Taking artistic thermal images is difficult. This is partly any equipment capable of producing images with anything like a pleasing resolution is extremely expensive and often militarily sensitive, but the way objects give off thermal wavelengths can appear to be unpredictable and somewhat messy.
In recent years, thermal cameras have appeared with resolutions comparable with HD TV, and the BBC Natural History Unit shot some fascinating night-time sequences with such a camera. I'm sure military applications have achieved even higher resolution.
Richard Mosse's book 'Incoming', published last year (and apologies for being slow to pick up on this) ventures into military territory with a combination of high resolution and a very long lens. The military have used long lenses with near-infrared photography since the second world war, making use of NIR's capability to cut through haze over long distances, over 100 miles under the right conditions. Such photos were taken with the equivalent of a telescope as the lens. (There are examples of long distance infrared photos taken using astronomical telescopes, notably at Lick Observatory in the early 1920s.) Now thermal imaging technology allows hyper-long-distance shots using far-infrared radiation, and Richard Mosse got his hands on such a device, with the intention of shooting a movie illustrating the plight of refugees. The results are, in turn, illustrated in the 'Incoming' book.
With this level of detail, and a straight monochromatic palette, the results are a surreal version of conventional photography; just slightly out of phase with our usual perception. The down-side is that the camera, with its power-pack, weighed about the same as a person and was mounted in a Steadicam designed for 'old fashioned' 35mm movies. Even then, it lacked anything like conventional controls and had to be operated using an X-Box controller.
Some of the shots are from a great distance, and exhibit extreme telephoto effects. Some are much more naturalistic, with the high resolution exposing folds of clothing and perspiration on skin. Some are tight crops. Some, in the book, may not be true thermal images. Can you take a thermal image of the moon? I'm not sure, but to be honest in this context I don't care. This camera is designed for remote surveillance and is described as allowing us "to see the way missiles see" so it may even be a hybrid.
Incoming's form factor is also unusual. It's around 7-inches square, over an inch thick, with black edges. Everything is full-bleed with a prevalence of black, and the ink has both a metallic sheen and a slightly oily smell. You don't so much read it as become immersed in it. Almost all pages are images, with two essays at the end one entitles "Biopolitics and the rights of man", byGiorgio Agamben, the other by Mosse himself documenting the process he and his team undertook.
More info can be found on the Mack web site, from which you can order the book as well.
Incoming by Richard Mosse
Published by Mack
576 pages
280 tritone plates
17.5 cm x 19.7 cm
€40.00 £35.00 $45.00
I have always wanted to have the opportunity to take images with a high resolution thermal camera. Some time ago I did do some shooting with the small Flir thermal imager that fits onto an iPhone, the Flir One, but this only has a thermal resolution of 80 by 60 pixels. My chance to experiment with a higher resolution device at IBC was thwarted by the courier company who sent it to Brussels instead of Amsterdam.
So in full envy mode I saw an excellent set of thermal images in the Guardian today. It's not easy to be artistic given the nature of the bizarre world of the far infrared, but photographer Grey Hutton has done just that. He also understands just how far infrared radiation behaves ... and, no, you can not see through walls or even glass.
I recommend you look at his images, both on the Guardian web site - Traces of warmth: thermal images of London's homeless - and his own website at www.greyhutton.com. He promises some thermal images from Berlin later, so we should keep checking. To be honest, his are the best artistic thermal images I have ever seen, and a poignant way to document homelessness at a really cold time.
In a similar vein I also found 328 of Joseph Giacomin's thermal images on the Getty stock photo site. If you search for infrared on the Getty site you will find quite a few nice images, mostly near-infrared. Here is one of Joseph's:
Last June I had a chance to look at the Flir One thermal add-on for the iPhone. This was based on Flir's tiny Lepton bolometer. This has a resolution of 80 by 60 pixels and is aimed at OEMs to incorporate in various devices.
The latest is an Android mobile phone from Reading UK-based CAT called the S60, which was launched yesterday at the Mobile World Congress.
The CAT literature doesn't mention thermal resolution, although there is some online speculation that Flir's Lepton is now available with 160 by 120 pixel resolution, as reported by Ars Technica last August. Whatever it is, the CAT device seems to make use of the same blending technology that the Flir one uses to give false-resolution to the thermal image, which makes it much more useful. The visible and thermal cameras are also much closer together in the CAT, which will reduce need to correct the parallax errors at close distances that the original Flir One exhibited.
This is still not really of a sufficient 'quality' to be an artistic imaging device, but if you're a plumber, heating engineer or electrician this is a kind of tool that will soon be making its way into your toolbox.
You can see the BBC's Rory Cellan-Jones trying one out, and chatting to 'the man from CAT' in this video clip.
A recent article in Scientific American, Ultrathin Graphene Could Improve Night-Vision Tech, reports on research at a number of labs in the United States on a method to produce room temperature thermal sensors based on 'sheets' of graphene. The original paper abstract says ...
By integrating graphene based photothermo-electric detectors with micromachined silicon nitride membranes, we are able to achieve room temperature responsivities on the order of ∼7–9 V/W (at λ = 10.6 μm), with a time constant of ∼23 ms.
Of course it's not as simple as a single sheet. The team have not only used graphene for the sensor itself but use thin strips to graphene to hold and thermally isolate the sensor from the main substrate.
Graphene-Based Thermopile for Thermal Imaging Applications
Allen L. Hsu, Patrick K. Herring, Nathaniel M. Gabor, Sungjae Ha, Yong Cheol Shin, Yi Song, Matthew Chin, Madan Dubey, Anantha P. Chandrakasan, Jing Kong, Pablo Jarillo-Herrero, and Tomás Palacios
Nano Letters 2015 15 (11), 7211-7216
DOI: 10.1021/acs.nanolett.5b01755
I've been hoping to have a closer look at one of the new breed of 'personal' thermal imaging cameras, and with the help of the Royal Photographic Society Journal I have been able to.
You may recall from earlier posts that this version of the FLIR One operates like a case for the iPhone 5 (more versatile versions are imminent) and uses the iPhone for viewing, operations and storage. The FLIR's case fits firmly onto the phone although it is in two parts so the thermal camera part can be easily unclipped if you don't want to carry it with you all the time. Fitting and removing the inner case to the phone is a little tricky and some users report breaking it ... so be careful. Clipped together the device is obviously heavier than the iPhone but not unduly so, and the whole thing still slips easily into a pocket. The two devices communicate via the Lightning connector and the thermal camera does not take any power from the camera; it has its own battery which is charged separately.
To operate the camera you pull down a slider switch half way until it clicks and turn on the free downloaded app. You are then prompted to pull and hold the slider a bit further, to calibrate the camera, after which you're ready to go. It's point and shoot, with options to change the colour palette, hold exposure, and select either a still photo, a panorama, time-lapse or a movie to shoot.
Thermal resolution is low, at 80 by 60 pixels, but the software neatly combines this with information from a coincident (almost) 640 by 480 visual camera, adding something like the Photoshop edges filter to form a hybrid image. For most purposes, this process, called MSX, completely ameliorates the low resolution thermal image. As the two cameras are not completely coincident there will be parallax errors if you shoot close-up. It is possible to correct for this (but sometimes I forgot). You can choose between several colour palettes. A thermal image is monochromatic but adding false colour can help show the distribution of temperatures. You can change the palette of a shot later, but for some reason the camera shrinks the image to 516 by 387 if you do this, which is weird. Another thing to note is that a FLIR logo is added to every image shot, which is slightly intrusive (imagine if Nikon or Canon did this) but is par for the course with their devices.
Straight out of the box you can shoot useful diagnostic images. For example, here is a shot that shows a cold carafe of water in the foreground and in the distance you can see a warm radiator and also the heat trace of warm pipes going up inside the wall above it. This uses a grey palette ... dark is cold and white is hot (relatively, the range is actually 12.8 to 21.2 degrees C).
Here's a shot with the temperature indicator turned on which shows heat spots of a group of transformers powering my broadband and phone equipment (iron palette). The FLIR One has a number of emissivity settings with a matte setting being the recommended one. Emissivity denotes how much infrared thermal radiation something radiates compared to what it should do if it were a theoretical 'black body'. Knowing the emissivity helps you know how accurate a remote temperature measurement is. The FLIR One has four settings for this, from matte to glossy, which is fewer that a fully professional thermal camera might have but is still useful.
I've no doubt a thermal camera such as this is a useful practical tool, especially in DIY for tracing heat loss and heating pipes (amazon.com buyers are notably enthusiastic about this kind of application), but I'm not so sure about its artistic possibilities. The low thermal resolution makes it difficult to take images as atmospheric as those that Joseph Giacomin takes, especially since I couldn't work out how to record only a thermal image with no visual embellishment. That said, it's easy to take fun thermal images and the images certainly attract attention.
I showed the FLIR One to a visiting heating engineer who immediately said he'd ask his boss for one, although for a professional with no need for panoramas or movies the new FLIR C2 [data sheet] is likely to be a better bet, especially since it is a self-contained unit with a similar price point and better analytical features.
The FLIR One in this form factor is available now from places such as the Apple store and Amazon (£180). I would wait for the newer model, which clips to the bottom of an Apple or Android phone or an iPad and should be a bit more future proof. From an artistic point of view I will pass, despite the low price. I think Joseph has convincingly demonstrated that a 640 by 480 thermal image has real artistic possibilities but I am less excited by the low resolution of the FLIR One. However this, and similar cameras, will show whether there is a market for less wallet-busting thermal cameras ... so I am delighted to see it and ignoring my arty pretensions I do think it's an impressive device and really easy to use.
To finish here are a few more results I got from the camera. Click for full size (640 by 480) versions.
The obligatory selfie. Normally with a thermal camera you wouldn't see my eyes through the glasses, but here the special processing does show them.
These thermal wavelengths (of the order of 10 µm) don't go through glass but they will go through some plastics. In this case you can see my hand inside a black bin liner. (The hand isn't touching the bag ... that would be cheating.)
The London Eye from Westminster Bridge. The thing growing out of the guy's head isn't a new tower block ... it's a lamppost on the bridge!
This shot, of the cab of a steam locomotive, demonstrates a colour palette that shows the very hot spots in red.
And finally some movie. Shooting a movie is straightforward, although in some circumstances you should lock the exposure (called span) to avoid changes to the palette mid-shot. The three scenes are of a London tube train (Victoria line) and a subsurface line (Circle etc) ... here you can see how the tube train, which runs deep underground, shows as warmer in relation to the platform than the subsurface one, which is at pretty much the same temperature. The wheels show very hot, as the trains are braking as they come into the stations. The third scene is of a loco at the Yarwell halt on the Nene Valley Railway, running to change ends before pulling a train towards Peterborough. I was surprised to see the hotspot at the front of the loco and by how relatively cool most of it was.
Many thanks to Dr Chris Lavers of the University of Plymouth for sending over unusual views of last week's partial solar eclipse. Here's an example ...
This was taken in the south west of England with a FLIR 320 by 240 pixel E320 thermal imaging camera. This camera covers a range of 7.5 to 13 µm, which includes a substantial atmospheric window around 10 µm.
I've mentioned Joseph Giacomin's artistic thermal images in previous posts. This is a rare art, not least because the cameras are either very expensive or of low resolution (or sometimes both).
Members of the Royal Photographic Society can get a background briefing from him in the latest edition of The Journal, entitled Heat and Light (page 802). It's clear explanation of the principles of thermography and well worth a read.
Digging around after my piece last week on the FLIR One I discovered that this isn't the only game in town when it comes to relatively inexpensive thermal imagers using smart phones for control.
I have already mentioned Andy Rawson's lo-res device, which I was told about in July 2013. Andy's web site now tells us that they have discontinued the camera because other inexpensive thermal cameras with higher resolution are now available. There was, however, another camera in the pipeline called Hema-Imager from Erik Beall, but this failed to reach its Kickstarter target. I get the feeling that these guys won't be giving up, and I wish them luck.
Israeli company Opgal have produced the Therm-App, which uses an Android phone as controller. This is more expensive that the FLIR One but has a higher thermal resolution (384 x 288 pixels and 7.4 to 14 microns ... which, of course, includes human body temperature) with a current price of $999 (full price $1600). This camera clips onto the back of your phone and connects via a small cable.
California-based Seek Thermal have announced a 206 by 156 pixel thermal camera add-on for both Android and iOS. It connects via micro USB or Lightning (depending on the device)and slots onto the bottom of your smart phone. Examples on their web site look good and so do the specs: vanadium oxide microbolometer detecting between 7.2 and 13 microns. The price, in the US, is $199.
All the companies marketing these inexpensive thermal cameras hope to build a market to help DIY (aka home improvement) by detecting hidden pipes and checking the temperature of food as well as seeing in the dark security.
There may be even more such devices out there ... if you know of one then let me know in the comments.
FLIR's iPhone add-on thermal camera, the FLIR One, which I discussed back in January is now available from the US Apple Store. Availability in other territories should follow.
It turns out that the resolution of the thermal camera is 80 by 60 pixels but this is merged with a 640 by 480 pixel visible light camera and the image is enhanced depending on which mode you use. The image below is a composite image used by FLIR for promotion.
You can see the softness of the thermal information but I have to admit the blend with the visual image makes for a quite usable result.
The cost in the US is $350 and you have to use an iPhone 5 or 5s. The device will not fit on either iPhone 6 and it would seem that FLIR have no plans to produce a new one. That was always the risk but this still brings thermal imaging into a completely new area of use, appealing to small businesses and hobbyists alike.
Gizmodo got their hands on one in August and explain just what you might want to do with it (if you don't know already). They also did a review, but they were unsure whether it's worth the money. Given the usual way tech prices inflate as they cross the Atlantic that may be a bigger issue over here in the UK. That said, to echo one of the commentators on the review, it's still cheap for a thermal imager.
Thermal imaging cameras being as expensive as they are, it's interesting to see how observation of animal behaviour can provide clues to some aspects of temperature distribution in the environment. The classic is how to detect that a car has only recently arrived at a property ... if you can't touch the bonnet (hood). A thermal camera will show a warm spot on the bonnet, or (in classic detective mode) you might see that a cat has decided to lie there. Pigeons can also be useful detectors. You will often see birds roosting on top of one building in a group and this is often simply because that roof is warmer; either because of a local heat source such as an air outlet or because that roof is less insulated than the others. Snow will fulfil the same function.
A similar, but inverse, phenomenon has been observed by researchers in Australia. They were using thermal imaging to study how koalas regulate their body temperature, given the hot climate. Hugging trees was one mechanism, the tree trunk being cooler than the surroundings. The animals were observed moving from the top leaves where they feed in winter down to cooler parts of the tree in summer. Conveniently this would provide a perch where the koala could either lie spread on top of a shady branch (as some big cats are seen to do) or wedge themselves in a junction between a large branch and the trunk. Thermal imaging revealed how the koala uses the tree trunk and/or branch as a heat sink.
The study is published (freely accessible) in the Royal Society journal Biology Letters [Biol. Lett. June 2014 vol. 10 no. 6 20140235] and you can read (and see) more on the BBC web site which also outlines other research into how animals can exploit microclimates in trees and other means to combat high temperatures.
Similar themes can be explored from an earlier blog post on toucans and trees.
As I was in the West End last week I went over to the new Photographers Gallery just off Oxford Street to have a look at Richard Mosse's extraordinary infrared photographs from the Congo (see the previous post). The good news is they look stunning in the huge prints on show. I was very surprised by just how small the grain in the film is, so I have to assume the aerochrome was actually developed using the 'correct' aerochrome process rather than the E6 most of us used. The bad news is that there are only a handful of the prints on display and I had hoped to see more.
So, I went down to the bookshop in the basement and chatted with the very helpful sales assistant. I had hoped to get a copy of either of the books of Mosse's photos but that was not to be. They are completely sold out, not just at the Gallery but everywhere it seems, and are now selling for high prices.
Despite being disappointed by this (and kicking myself for not buying his Infra book online from Aperture when I could) I got to thinking that this took the book into the realm of photographic collectors items. They may well be the first books of infrared photography to truly get there, and prize-winning photography at that. I know there are a couple of other IR photo books that go for high prices but I think these are in a class of their own.
Changing wavelength, I am getting a little worried that FLIR's inexpensive iPhone add-on thermal camera may be having difficulties. The general consensus in the Apple rumour mill is that the iPhone 6 will be along soon and will have a larger form factor. This means that the FLIR One, as publicised, will be designed to use an obsolescent smart phone body. I still hope that the promise it showed when previewed at CES in January will be realised and it would definitely be a game changer for a wider use of thermal imaging.
Last June, I noted research in Singapore which promised a wide-ranging imaging sensor based on graphene. The hyperspectral detection of graphene ranges from ultraviolet to far infrared but there has been a problem with very low sensitivity of the single layer of carbon atoms.
A paper in Nature Nanotechnology, published on March 16 2014, outlines a method devised by researchers at the University of Michigan whereby electrons freed by photons hitting a first layer of graphene tunnel through an insulating barrier layer and into a second graphene layer. This affects current flowing through the second graphene layer and this is what is detected. The result is a dramatic increase in sensitivity as well as IR detectors that perform well at room temperatures. This is all explained in a press release from the University of Michigan. The 'trick' was to look into how the signal could be amplified, rather than making the signal itself stronger. (I haven't read the whole paper but I would ask what noise does this generate.)
"We can make the entire design super-thin," said Zhaohui Zhong, assistant professor of electrical and computer engineering at Michigan, and one of the inventors. "It can be stacked on a contact lens or integrated with a cell phone." This mention of contact lenses led the Register to ask "Want to see at night? Here comes the infrared CONTACT LENS".
A patent, 'Photodetector based on double layer heterostructures', has been applied for.
Professor Joseph Giacomin and his artistic thermal images have featured before on this blog.
Thermal art is basically as rare as hen's teeth, mainly because thermal cameras are very expensive beasts (although that may be about to change).
Rush Hour by Joseph Giacomin
He has now launched a web site dedicated to his thermograms (or is it thermographs?): Perception Enhancement Studios with a fascinating collection of images captured using a 320 by 240 pixel camera. This is standard res for thermal devices, anything higher counts as HD. One useful feature is that you can choose to view the set of images from three tonal scales. Two are false colour, red-blue and iron, and the third is grey-scale. Personally, I prefer the grey-scale. The false colour scales are designed to exaggerate differences in temperatures, which I feel can often be a bit over the top for art. That said, false colour shouldn't be ignored and I suggest you go to the web site and make your own mind up.
Deianira by Joseph Giacomin
I have come across other artistic thermal images, but I find Joseph usually has the edge when it comes to artistic flair (or should that be artistic Flir ... in-joke).
The leading manufacturer of thermal images, FLIR, have launched a prosumer thermal imager at CES. I mentioned the $200 IR-Blue in an earlier post but this new device appears to be much more like the existing thermal images we've seen from FLIR and others while having a retail price point of only $350. This is an amazing price point and opens up a whole raft of new applications in a whole new market.
The unit fits onto an iPhone 5 (and 5s) and uses an iPhone app for control, display and recording - including movies - linking via USB. I couldn't find any information on spatial resolution but my guess is that the display is something like 320 pixels across. This is augmented by the ability to blend in a visual image to provide some detail to help identify features. The thermal core is FLIR's Lepton, which is a tiny microbolometer-based unit designed for consumer manufacturing scale. The thermal range for the scene is zero to 100 Celsius with a resolution of a tenth of a degree, which should suffice for most consumer uses and will certainly pick out a person in the dark.
What is telling is that much of the FLIR promotional material is aimed at people who don't even really know what thermal imaging is or what it can do. A thermal image is (IIRC) regarded as a search in the US so there may be privacy concerns but a thermal image of a person does not show any significant detail. (That judgement was based partly on thermal imaging devices not being generally available to the public.) Hopefully we won't see any of the hysteria that greeted near-infrared photography and its so-called (and insignificant) X-Ray capability! Oh, and to save you asking, it's the area between the eyes and the bridge of the nose that best shows the body temperature, not the forehead.
I see this as a really significant piece of kit and welcome FLIR's initiative. Worldwide launch is Spring 2014 'at popular retail outlets'.
The BBC's new natural history series The Great British Year has shown some fascinating, and very artistic, uses of thermal imagery. (Best if you expand the videos ... but sorry they probably won't work outside the UK.)
And there's a movie showing something of the technology.
Shows you don't have to wander the plains of Africa to get exciting thermal footage, and I have to say it's nice to see something more subtle than the usual blue/red heat pattern. Also worth a read (and with the 'usual' colouring in many cases) is a web page on 10 wildlife secrets revealed by thermal cameras ... even a hot plant!
Your usual thermal imaging camera costs thousands of dollars, often tens of thousands. Now a guy named Andy Rawson in the US has developed (with funding via Kickstarter) a much cheaper device called IR-Blue. It uses your iPhone (or many similar) to connect via Bluetooth to both display the thermal image and superimpose it on a visual image, as the video above will show.
The down side is that IR-Blue has very limited resolution with only 64 'zones' of IR image and those concentrated in a central band. So you won't get a detailed thermal image. That said, it's cheap ($160 kit or $195 assembled) and has real-world applications such as hot-spot-tracing. And for that price it's a fun thing to have ... and it does 'see' in the dark.
[My thanks to open-hardware enthusiast Andrew Back for pointing this out.]
The manhunt for the remaining Boston Marathon bomber ended when he was discovered hiding in a boat in a back yard. As this page from NBC's Photo Blog shows, the fugitive's body can clearly be seen even though he was underneath a kind of tarpaulin that was protecting the boat from the weather. There's (over compressed) movie (pity about the commercial) but, further down, a couple of hi-res stills.
A further story explains more about the thermal imaging and, eventually, explodes the myth that you can see outlines of people through walls using far infrared/thermal imaging ... despite what CSI would have us believe. You can however see through thin sheets of plastic, such as a bin liner, at these wavelengths which can not be imaged with a conventional camera.
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