[Gimp-user] Colour Correction In Camera Trap Images

["AUGUST, KATHERINE (PGR)" <k august 18 abdn ac uk>]

Hello,

I am a PhD student at the University of Aberdeen, Scotland. My work is looking at the population dynamics of 
goshawks, a forest specialist bird of prey, in the northern UK. As part of the monitoring, I use camera traps 
to get images of individual goshawks. I now wish to compare the eye colour of known age individuals to see if 
I can determine a relationship between eye colour and age (goshawk eyes start pale yellow and become redder 
with age, but this has never been quantified before).

In the camera setup, I include a greyscale chart to act as a colour standard as images are taken in a variety 
of lightings. I also wish to determine if the goshawk leg is a consistent enough colour that it could be used 
as a standard.

I am using GIMP to get the pixel RGB values for the eye, leg and various greyscale squares. I feed this into 
a dataset and would like to use the different colour standards to correct the eye colour. This would then 
allow me to compare the repeatability of the various standards across images of the same individual. From 
speaking to amateur photographers, I believe the usual method would be to correct the image within GIMP, but 
as I want to use multiple colour standards, I would prefer not to alter the image itself.

As it can be done within GIMP, I am assuming there is already some kind of conversion algorithm/equation for 
doing the colour correction. So, my query is, what is this conversion equation?

Any help would be greatly appreciated and appropriately recognised!

Thank you,

Katie

Katherine August
PhD Researcher NERC Case Partnership

University of Aberdeen
Room 422 Zoology Building
Tillydrone Avenue
Aberdeen
AB24 2TZ
Email: k august 18 abdn ac uk<mailto:k august 18 abdn ac uk>

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The University of Aberdeen is a charity registered in Scotland, No SC013683.
Tha Oilthigh Obar Dheathain na charthannas cl?raichte ann an Alba, ?ir. SC013683.