Re: Help with Infrered images fron a plane

["Willem-Jan Markerink" <w.j.markerink@xxxxx>]

On  6 Nov 00 at 21:06, Ing. Jose Plano wrote:

> Hi to all,
> My name is Jose, and I planinig to take photos from an air-plane to the
> crops, but my problem is... that I dont know how I can do it.
> 
> 1.- May I use a digital camera? 

Sure, compared to analog IR-film, digital is an alternative....but:

> 2.- wich is the best for it?
> 3.- The range in IR that I wont to cover are from 0,4 to 2,8 um, there are
> any     filters for this range?

um is micrometer, 10^-6m, while photographers mostly talk about 
nanometers, 10^-9....and 0.4-2.8um translates to 400-2800nm....from 
which 400-780nm isn't IR at all, only the part above 780nm....
[as a reference, 380-780nm is the visible spectrum, 380nm on the border 
of UV/Violet, 780nm on the border of red/IR]

However, IR-film only covers the invisible range 780-940nm (plus a 
significant part visible below that btw), so with film you cannot solve your 
entire problem....digital cameras go a little big higher, 
1000-1100nm, but you still need a thermal-camera for the spectrum 
above that....and if my memory is correct, most thermal cameras can 
be devided in two types, one type covering 3000-5000nm, and one 
type covering 7000-12000nm....so you would still not see below your 
2800nm....I assume sensors exist for your application, but they are 
probably much less common.

> 4.- How I can calculate an a spatial precision with the heigth of the
> air-plane     and the focal distance ?

Outch, that's a bit over my head...8-))
 
> I know that are expensive cameras for this work, but I planing start with a
> cheap system at first.

For the aerial aspect of your question, you might consider 
s_ubscribing to the Aerial Photography Mailinglist....see canned 
message below for instructions how to s_ubscribe:

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Check my homepage for the link to the PhotoForum site, 
where you can find a large overview of photo related mailinglists:

http://www.a1.nl/phomepag/markerink/mainpage.htm

This PhotoForum site also offers a nifty 'mailto:' -form for direct 
subscription, and more important: with the same ease for 
uns_ubscribing....the fastest way to uns_ubscribe a dozen of lists 
shortly before going on holiday....any other method is tedious at 
best.
Store that URL, and you'll never be searching for either command or 
list-address related to any list....it's all on one page.

Further down my homepage you will also find links to general 
overviews of mailinglists (more than just photo-related).

Also on the above URL is a full list of photo/video/image related 
newsgroups on Usenet.
 


--                 
Bye,

Willem-Jan Markerink

      The desire to understand 
is sometimes far less intelligent than
     the inability to understand

<w.j.markerink@xxxxx>
[note: 'a-one' & 'en-el'!]
*
****
*******
******************************************************
*  To remove yourself from this list, send:          *
*         UNSUBSCRIBE INFRARED                       *
*       to                                           *
*         MAJORDOMO@xxxxx                            *
*----------------------------------------------------*
*   For the IR-FAQ, IR-Gallery and heaps of links:   *
*  http://www.a1.nl/phomepag/markerink/mainpage.htm  *
******************************************************