**
Red chanel : NIR reflected (not just white in B/W image of plain NDVI )
Green Chanel : NIR +Red reflected (not just red as in plain NRG )
Blue channel : Green reflected
How it works :
One shoot of the scene is shot at visible plus NIR ,(customised IR camera without any filter ..)
one another shot at NIR only (<=...plastic filter cap (dark purple) from a remote contol used to cut visible light ) ..
The "visible + Nir" photo then duplicated.
The first of the two duplicates , becomes a B/W (black'n'white ) pic with a
red filtering (
red wls pass as white light in processed B/W pic ) .
This is the "indicator layer " of how much red is reflected,from plant .The brighter ,the more reds are reflected.
This layer becomes the
green chanel of final NDVI / NRG pic .
(so you see reds as greens/yellows .....)
The second duplicate layer becomes another one B/W pic with a
green filtering (
green wls pass as white light in processed B/W pic ) .
This is the "indicator layer " of how much green is reflected,from plant .The brighter ,the more green wls are reflected.
This layer becomes the
blue chanel of final NDVI / NRG pic .(so you see greens as blues .....)
The "only NIR " photo stays as is (colour photo) and becomes the
red chanel of final NDVI / NRG pic.
(so you see FR/NIR as reds ... )
In final NDVI / NRG combined pic , the red colour is the reflected FR/NIR from plants....
If green is shown ,something red is there...(that is not photosynthesizing )
If blue is shown ,something green is there ..(that is not photosynthesizing) ..
-In plain NRG images ,all colors are as in reality(greens are greens ,blues are blues ,yellows are yellows ,ect ) ,
except reds which are FR/NIR ...And 'real' reds which are more ambers/yellows ....
-In plain NDVI images ,(which are always B/W or monochromatic ,as being ,in fact a 'photo imaged' ratio .... ) ,
the ' light '(white ) is " FR/NIR - Reds " reflected , while the 'shadows (blacks )are "FR/NIR + Reds ",reflected...
..plain NDVI=> ..
Blue=FRL - RL ..(Reflected to camera => red is absorbed )
Black = FR + R (Reflected to camera )
Or with better IR cut filter (better "grade " reflectance analysis ,but worse pic quality )
..
The yellow area (maximal red wls absorbtion ,max FR/NIR reflectance/emission ),is exactly
under the panel of 10x CW ,10 x 630 nm ,2 x WW & 2x UVA/Violet....
Hmmmm...Although yellow,might mean " overloaded " photosynthetic systems....
Leaves ,under those panels seem of a deep green /bluish -kinda color...
Kinda under stress....
We've got some protective anthocyanins production there ,maybe ?
Weird...