Estimate color concentration

[blue121]

Hi everyone.
I write to ask for one advice, I'm not an expert, so I apologize if I will write nonsense.

For the purposes of scientific research, I should estimate the yellow concentration of a bird's chest, which will be captured with a video camera in nature. The idea is to use a graphics program such as photoshop to detect the concentration of yellow from the image frame. However, to prevent that the different shades of sun light can affect the color of the yellow shade in the video (and therefore in the photo), I have thought to put a piece of yellow paper, always the same, in all bird roost where there is the animals (which act as a colorchecker I think). So, I would have in the photo the animal with a certain shade of color in the chest to identify in some way, and behind it, a piece of yellow paper, with a known shade of color. I think it can be useful because my problem is that the different shade of sun light could change the shade of yellow that I have to identify, and therefore I need a way to resolve the problem of ambient light. So I would like to place a colorchecker, and compare the chest tone to the known tone of the colorchecker, to estimate the true yellow tone of the animal.

I need some ideas on how to estimate the concentration of yellow in the chest of these animals. This concentration will then be compared between birds in different areas, following the hypothesis that different areas imply different shades of yellow in the chest. Can it be done with photoshop? What do you think?

Thanks so much

 

[IamSam]

Maybe I'm not understanding, but if it's just a matter of identifying colors, the Color Sampler Tool should provide you with what you require.

In this photo.... (click to enlarge)


I have Identified three areas of color....


1. R: 229 G: 67 B: 28
C:4% M:89% Y:100%. K:1%

2. R: 251 G: 214 B: 37
C:3% M:13% Y:94%. K:0%

3. R: 250 G: 175 B: 47
C:1% M:35% Y:93%. K:0%

These would be a very small sampling of the tonal values of this particular area of the birds chest feathers.

 

[IamSam]

I need some ideas on how to estimate the concentration of yellow in the chest of these animals. This concentration will then be compared between birds in different areas, following the hypothesis that different areas imply different shades of yellow in the chest. Can it be done with photoshop?

Yes. If you sampled images of birds of the same species taken from different regions, you could see the differences in the tonal values of the birds chest feathers. But also bare in mind that this could also vary from bird to bird...........even in the same family.

 

[blue121]

Thank you very much!
Basically the birds are all great tit, but from different areas. The yellow of the chest reflects the concentration of carotenoids, so I would have to measure the concentration of yellow by photo, to get an idea of how many corotenoids there are, and compare these "chest yellows" among the great tit in different areas. There are some statistical analyzes to do, but first i need to have a numerical value that reflects me "how much yellow there is". So maybe yes, with the Color Sampler Tool I can have a numerical value that quantifies the yellow color, I thinks it's a good way,thank you : )

So yes, they are all the same birds. But, you gave me a great hint: indeed, in each yellow zone of the great tit there are different yellow, so what I should do is something like this:
1 - photograph the bird (easy)
2 - cut out a square from the yellow chest in photo, (red in the photo below), and blend all the yellow shadows into that, so as to have a unique value, only one yellow.
3 - now there is the problem that sunlight could affect the yellow of birds, and therefore animals photographed in different environments have different yellows. But they are not their true colors. So having a colorchecker behind the animal, could it allow me to correct the value somehow?

Thank you for the time you have dedicated to me