Thanks to the Press
Officer at London Zoo allowing access with less than 24 hours
notice, one of the most rewarding series of shots with the
borrowed thermal imaging camera, happened on the day before it
was due to be returned, on a cold, drizzly 3 January 2007.
Several of the images later made it to the national national
newspapers and are now in demand internationally. Amateur
Photographer magazine wanted to do a feature on the piece and
so, with support from FLIR Systems and the zoo, another day of
shooting took place on a very warm and sunny 27 May. Amateur
Photographer's feature should be ready in July.
The May images are not so good
as January's as the ambient heat was closer to the animals' in
the outdoor compounds. As can be seen in the giraffe picture to
the right, the heat of the sun had warmed the outside up so much
that hard surfaces had become quite hot.
In the gorilla compound,
the chief male sat in a cool cave whilst his subordinates had to
make do with the outside. Notice the red (hot) and white
(hotter) on the two subordinate gorillas, whilst the big male languished
in the cool (dark blue though to black) of the cave that,
had he been generous enough, would have had room for three.
Note the red (hot) and white (hotter) heat detected on the
subordinate gorillas and the relative lack of these colors on
the mainly yellow (warm) and green (cooler) chief.
Here is a sample of the base images captured. This 'base image
set', like all others, is still being reviewed and worked on, as
there are so many different ways to manipulate them.
Each original image has, within it, details of the average
temperature identified for each pixel. The temperature range
that is visually represented can be changed in various ways and
an appropriate temperature-color scale can be added when
The original thermal images can
also be stitched together and cropped. Experiments are
ongoing and various examples of work on the original animal pictures
will soon be on the Experiments page. More images will be added
to this page soon.
These first four butterfly pictures, show
how one original thermal image can be reinterpreted though
different heat-color spectrums of the same temperature
The respective heat
spectra used are: 'Greyscale' (black=cold, white=hot); 'IronScale'
(black=cold, through purple, red, and yellow to white=hot); 'RainbowHC'
(black=cold, through purple, blue, green, yellow, brown, and red
to white=hot, where the infra-red processor has added a hard
edge to each area of defined average temperature) and finally,
'Rainbow' (black=cold, through dark blue, light blue, green,
yellow and then red to white=hot)
On the left is an
enlarged crop of a butterfly picture along with an appropriate
temperature scale. What is interesting is the fact that the
butterfly's abdomen looks hotter than its thorax. This seems odd
as one would guess that its heavily worked wing muscles would make
the thorax hotter. Perhaps a butterfly anatomist might offer an
Heat from delicate butterfly veins can be seen in the picture to
the top right. Other heat sources can also be seen on this
yellow-warm table top in the Zoo's butterfly house, but what are
To the bottom right is a normal picture taken at roughly the same
time. Can you identify all the heat sources? Notice also that,
virtually unseen in the visual picture, is a drop of water just
below the big butterfly's wing. Cooled by evaporation this shows up
as an additional green circle in the thermal image.
Often, a thermal image can be more colorful than a real image, as
can be seen in the comparison of real to thermal images of sacred
ibis (left) and penguins (below and right). The penguins' camouflage
probably helps protect them in the real world, from seals waiting
offshore to ambush them.
Clockwise, from top left, these
images focus on dealing with the cold. Remember to check each
thermal image's unique temperature - to color - scale. See how, in
winter, the llama's thick fur traps its body heat.
The flamingos' feathers perform a
similar trick and they even seem to slow the blood to one of their
legs to prevent further heat loss.
The camels have a thick winter
coat on top, but by late May this has largely fallen off (bottom
left) so that they can instead enjoy the heat of the sun.