I just saw a real nice article at Hackaday.com discussing a method and implementation for determining the perceived dominant color in an image. In a quick search I could not clearly find what algorithm/logic Hyperion is currently using to determine the output color(s); though it does a great job. Not necessarily a meant as an improvement, but this article might bring some inspiration for future development.
When someone can point me to the code/algorithm used by Hyperion; I'd love to get to know more about it --> someday I will probably build a FPGA based setup (I'm a FPGA/VHDL developer by daylight).
edit: just found some extra info in the linked articles about the Hue camera app