Processing LRGB and NIR

[smccully]

So i am having some trouble trying to figure out how to go about combining my additional NIR filters, i am wondering if somebody could an explanation or point out some resource that would help in combining L + R+ G+ B+ NIR1 (700 - 800) + NIR2 ( 800 - 900) + NIR3 (900 - 1000). At first i thought i would combine the NIR and RGB and then try to use the NIR as sort of alpha (opacity) channel. But i am not terribly sure how to do that.

[dave_galera]

HI,

NIR is normally combined as a luminance channel with the RGB as NIRRGB, however, as you already have Luminance you have the following options which are both worth trying.

Create synthetic Luminance by combining L + NIR1 + NIR2 + NIR3 then combine with RGB
OR
Create synthetic Luminance by combining NIR1 + NIR2 + NIR3 then combine with RGB and ignore the Luminance that you already have

Hope this helps

Dave

[Juan Conejero]

Vicent and I wrote a tutorial where we describe how we generated RGB images with Alhambra Survey data. We combined data acquired with 23 filters from 3500 Å to 9700 Å and the standard JHK NIR bands. We defined synthetic RGB filter sets by assigning different weights to each original filter band. This is a completely different way to face this problem, but I think you may find it interesting and hopefully applicable to your data.