Hello Dbaxter,
There are a number of good resources providing information on taking
infrared pictures using digital cameras. There do seem to be a few
things you *must* have to make this work.
- a digital camera that does not incorporate an IR filter (or if it
does, it can be removed); I suggest borrowing a camera from someone
else if your camera does not work well.
- the camera must also allow manual exposure settings
- a filter that blocks most visible light and lets red / IR
frequencies through. Several sites recommend the type of filters -
generally available at a good photography store or on line.
- a photo processing program (e.g., Photoshop) to adjust the image.
If you don't have a good program, tell me what kind of computer you
have in a clarification request and I'll see what I can recommend to
use at no (or low) cost.
A couple sites also suggest using a tripod to steady the camera (or in
one case to take multiple pictures w/ and w/o a special filter). The
first reference indicates exposures of about two seconds to get some
of the effects. A "good" camera may not have this problem - you will
have to try it out to see what works best.
Let's go through a few sites found using the search phrase
digital camera infrared
and describe the steps they recommend and the illustrations they
provide.
"Infrared photography with your digital camera"
http://www.wrotniak.net/photo/infrared/
A very extensive reference with a number of illustrations of images
from a variety of digital cameras. He describes IR filter selection,
the steps to take the images, and the steps on the computer to enhance
the images. There is also a nice example of the same picture taken on
a cloudy day and a sunny day to show the differences.
"Infrared basic for digital photographers"
http://www.cliffshade.com/dpfwiw/ir.htm
Another very extensive reference site. Be sure to scroll down to the
section titled "Honey, Where's the Remote" which provides a quick
check of your camera using the TV remote control. There is also an
extensive explanation of the difference between "red", "near
infrared", and "far infrared" - this part of the explanation may say
that determining heat loss from a building will be "hard"; I can't be
sure. This may be an area where some false coloring of the image after
the picture is taken can help highlight problem areas. The page ends
with an extensive set of links (that I won't try to repeat in this
answer).
Infrared digital photography
http://www.echeng.com/photo/infrared/
A much shorter reference, but much more oriented to things to try, see
what works, and solutions to problems. Another good list of links for
further resources
Shooting digital infrared
http://bermangraphics.com/press/infrared.htm
I am including this reference due to the nice picture at the top of
the page - move the mouse over the picture to switch from a normal
image to infrared. It highlights the image differences that you can
expect with your picture.
As a comparison, you should also look up
http://www.cocam.co.uk/CoCamWS/Infrared/INFRARED.HTM
which provides an explanation of infrared photography in general. Most
of the document addresses film based photos, but digital photography
is also described.
This certainly looks like something that can be done with the
equipment you have (or can buy at low cost). If you need some
additional information on post processing ideas (or anything else),
please use a clarification request.
--Maniac |
Request for Answer Clarification by
dbaxter-ga
on
29 Jan 2003 16:47 PST
Maniac, thank you for a fine job. I scanned the sites whose links you
provided and see that some of the them specifically say that heat
cannot be easily detected:
"Heat sources from objects such as engines put out most of their
radiated energy in the form of far-infrared, in the wavelength range
of 10-100 microns or so. To detect this you need special infrared
sensors, and generally they have to be cooled with liquid nitrogen or
other temperature regulators that can get you well below 0 C. (Just as
the inside of a camera has to be dark, the body of an IR detector
intended to detect heat has to be cool ...)"
"At room or body temperatures, thermal radiation lies in the far IR at
wavelengths of 3µ (3,000 nm) or longer—well beyond the reach of most
digital cameras, which peter out around 1.2µ. Another major imaging
hurdle in the thermal IR band is the atmosphere, which is highly
transparent at visible wavelengths (0.3-0.7µ) and gloriously
transparent at NIR wavelengths (0.7-1.4µ) but quite opaque at 5-8µ, as
shown here. Glass is also opaque above 5µ.
To "see" body heat in complete darkness, you'll have to give up your
CCD for something truly exotic, like the indium antimonide (InSb)
focal plane array IR sensor in the FLIR MilCAM, which operates in the
3-5µ band. Above 5µ, you'll also have to give up glass lenses. I
don't think we're in Kansas anymore, Toto."
I also noticed that none of the links you provided actually showed a
picture of a house, which makes me think it is not possible with
typical equipment.
Check out these links for IR pictures of houses showing heat loss:
http://sirtf.caltech.edu/EPO/IRapp/heatloss.html
http://www.boldstarinfrared.com/homeimages.html
I was hoping that the pc could post-process the subtle differences
that the digital camera might capture with an infrared filter but I
think the answer is that the typical digital camera + filter does not
capture the wave length of heat I am looking for, say room
temperature, or 70 degrees.
If you feel like offering more help with this I would be eager to see
it, but you have already earned more than the meager fee I was
offering.
Thanks for a nice job.
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