The Straight Dope

Go Back   Straight Dope Message Board > Main > Comments on Cecil's Columns/Staff Reports

Reply
 
Thread Tools Display Modes
  #1  
Old 03-09-2012, 12:55 AM
Jerry in Canada Jerry in Canada is offline
Guest
 
Join Date: Jul 2010
side note on color blindness

I recall seeing an article several years ago about a farmer in Saskatchewan (one of the new ones with a university degree) who had discovered a way to filter out the reflected wavelength of chlorophyll and developed a pair of sunglasses that allowed him to see diseased or infested plants long before they were visible to the naked eye, by removing the color of chlorophyll all of the foliage reverted to it's autumn coloration revealing significant changes in color that were masked by the chlorophyll green.

As an unexpected side bonus, the American military was said to have bought up the whole process, patents, models and experimental models; and the whole thing dropped off of the radar.

I can see why: I saw one image taken of a Tank, a 105mm Howitzer and a Truck at the edge if a field, in a treeline and covered all in Forest Camo Net.
In normal color they were practically invisible.

Filtered they stood out green against a background of yellow and orange; and you go back to the normal color and NOW you can see them.

Can you verify any of this ?

Thanks
Jerry in Canada

**********************************
LINK TO COLUMN: http://www.straightdope.com/columns/...nary-advantage

Last edited by C K Dexter Haven; 03-17-2012 at 08:09 AM.. Reason: Added link -- CKDH
Reply With Quote
Advertisements  
  #2  
Old 03-09-2012, 01:29 AM
sitchensis sitchensis is offline
Guest
 
Join Date: May 2010
I believe what you are talking about is infrared mapping. It has been used by the military in the past, but I don’t believe it is used very much today, thermal images seem to have surpassed infrared for military uses. Infrared photography can still be very useful in agriculture, in mapping moisture distribution on irrigated fields and in mapping certain types of plants for invasive and noxious weed studies.

Last edited by sitchensis; 03-09-2012 at 01:29 AM..
Reply With Quote
  #3  
Old 03-09-2012, 04:09 PM
gnoitall gnoitall is offline
Guest
 
Join Date: Jul 2009
Quote:
Originally Posted by sitchensis View Post
I believe what you are talking about is infrared mapping. It has been used by the military in the past, but I don’t believe it is used very much today, thermal images seem to have surpassed infrared for military uses. Infrared photography can still be very useful in agriculture, in mapping moisture distribution on irrigated fields and in mapping certain types of plants for invasive and noxious weed studies.
Many Earth-observing climate/weather satellites use combinations of infrared and visual light imaging (plus quite interesting processing algorithms) to detect the type and state of health of vegetation. Going waaaaay back to Landsat in the 1970s.

The selective use of visual light spectra along with IR is just a very sophisticated application of color-filtering sunglasses, if you think about it.

ETA: Here's the Landsat program's page about agricultural applications of Landsat sensing.

Last edited by gnoitall; 03-09-2012 at 04:11 PM..
Reply With Quote
  #4  
Old 03-12-2012, 06:29 PM
njtt njtt is offline
Guest
 
Join Date: Jul 2004
Clearly, Jerry in Canada's story about the farmer in Saskatchewan has nothing to do with infra-red sensing. Glasses that filter out the wavelength of chlorophyll will not somehow make the eyes sensitive to infra-red.

Incidentally, sitchensis, I am pretty sure that infra-red sensing/photography and thermal imaging are (in this context) exactly the same thing.

And
Quote:
Originally Posted by gnoitall View Post

The selective use of visual light spectra along with IR is just a very sophisticated application of color-filtering sunglasses, if you think about it.
as the human eye is insensitive (by definition) to infra-red, no it isn't, if you actually do think about it.

Last edited by njtt; 03-12-2012 at 06:29 PM..
Reply With Quote
Reply



Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 06:13 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.

Send questions for Cecil Adams to: cecil@chicagoreader.com

Send comments about this website to: webmaster@straightdope.com

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Publishers - interested in subscribing to the Straight Dope?
Write to: sdsubscriptions@chicagoreader.com.

Copyright 2013 Sun-Times Media, LLC.