Wednesday, 18 April 2018

Infrared photos on 'Britain from Above'

My attention was recently drawn to an amazing, and freely viewable, archive of aerial images on the Britain from Above site. This features images from the Aerofilms collection of 1.26 million negatives dating from 1919 to 2006 which also includes the AeroPictorial (1934-1960) and Airviews (1947-1991) collections.

As you probably expect, I tried a search on infrared and up came 39 hits, all from the 1930s. This is the link to that search and here is an example image ...


The photograph shows the River Thames in London from Westminster Bridge to the sea, seen from the west, and was taken in 1934.

As with all the images here, there is some patterning from the original negatives but they look to have been taken from the open cockpit of a biplane (wing struts are visible in some) and date from 1932, 1934 and 1937. In 1932, off-the-shelf infrared plates were just appearing in shops, from Kodak and Ilford (and possibly others) so this is really early days. The earliest images in the collection predate the aerial shots published in the Times, and are not of such good quality, but I count them as historic nonetheless.

If you're interested in further aerial infrared adventures from the 1930s then please check out my post Biggles shoots infrared photographs over Mount Everest.

Tuesday, 27 February 2018

Artistic thermography

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:

Embed from Getty Images

It looks as if the game is afoot for artistic thermography, despite the equipment being tens of thousands in cost. Glad to see it.

[March 21st: Grey's images from Berlin are now on his web site]

Monday, 26 February 2018

Near infrared optical coherence tomography

I recently had a bit of a false alarm, or a false positive in data terms, with my eyes. A routine eye test threw up a structural condition that could result in glaucoma and so I was sent off to visit a specialist eye clinic. As I said, the problem wasn't actually there, but in the course of the test I came across a use of near-infrared light that was new to me: OCT or Optical Coherence Tomography.

The test experience was somewhat like that slit-scan sequence from the movie 2001, with me seeing moving rectangles and triangles expanding and contracting in my field of view. The result was a cross-sectional view of my retinas looking something like this:


This is an OCT scan of the cross-section of a retina at 800nm with an axial resolution of 3µm. Near infrared will easily penetrate a few millimetres into human tissue and by using a pulsed laser and a lot of computing an image of this type (described as being like 'visual ultrasound') can be built up. If you want to see the techicalities (and some maths) then check out the Wikipedia entry. The particular equipment used for my test was by a company named Optovue.

[Image is copyright: GNU-FDL, origin medOCT-group, Dept of Med. Physics, Med. Univ. Vienna, Austria, 2004 via Wikipedia]

Thursday, 4 January 2018

Infrared or infra-red

Over time, the balance has shifted between these two names for the radiation with wavelengths beyond red. William Herschel, who discovered infrared radiation, called them calorific rays and the earliest citation is for the word infra-red in the Oxford English Dictionary is 1881 in Nature; a lecture on solar physics by Captain (later Sir) William de Wiveleslie Abney. In a paper the previous year Abney had called it ultra-red, presumably influenced by the term ultraviolet. (The term ultraviolet had appeared in a paper by Sir John Herschel in February 1840; although he preferred to call them lavender rays, considering ultraviolet to be an uncouth appellation).

I had, from my researches in newspapers and online, come to the conclusion that infra-red gave way to infrared in the 1960s and if you do a Google search on each term today you will find that infra-red nets approximately 2.47 million hits while infrared nets 38.4 million.

Having discovered Google's Ngram tool I thought I'd run the terms through that. This is the result (infrared is in blue) ...


In this case, based on the words in books Google has scanned, we see a distinct cross-over in 1940. Click on the image to go to the actual Ngram result. I have included infra red, but there are very few instances of that and some are errors where the hyphen was missed out. There are some results prior to 1880 but on closer inspection they seem to be spurious, either due to incorrect document dating or scanning errors.

[Citation for Google Ngram research: Jean-Baptiste Michel*, Yuan Kui Shen, Aviva Presser Aiden, Adrian Veres, Matthew K. Gray, William Brockman, The Google Books Team, Joseph P. Pickett, Dale Hoiberg, Dan Clancy, Peter Norvig, Jon Orwant, Steven Pinker, Martin A. Nowak, and Erez Lieberman Aiden*. Quantitative Analysis of Culture Using Millions of Digitized Books. Science (Published online ahead of print: 12/16/2010)]

Thursday, 7 December 2017

APS biography of Professor Wood

The American Physical Society published a biography of Professor RW Wood in October. It was part of their This Month in Physics History series and commemorated Wood's Royal Photographic Society lecture in 1910. (The biog says this was the first publication of infrared photographs, but that was actually in The Century Magazine in February 1910.)

If you are unfamiliar with this fascinating, and omnitalented, chap then I suggest you give the piece a read:

www.aps.org/publications/apsnews/201710/physicshistory.cfm

[Thanks to Professor Paul Feldman of Johns Hopkins for the heads up]