I'm not totally convinced this is the right approach knowing your 'relative' requirements..
Unless there is some sort of pre-defined list.. (and I think this would have to be dynamic in some sort of way)..
How is '93' yo relative going to understand a bunch of RGB values displayed on a screen?
Depending on the available light.... I would guess this sensor can return slightly different values each time.
I dont think this project is very viable.
You wouldnt really be able to tell if the sensor if seeing the same 'thread'.. but returning a slightly different value based on ambient lighting..etc.. (or any other external influence)... or if it truly is a thread that is a shade different?
- I suppose it all depends on how granular you need to get?
I almost feel this is would be better represented if you could check the 'item' for color.. and then display the COLOR (like a color picker).. and not a textual name or RGB values...