I helped build a similar tool at 99designs. I blogged a bit about how we built it here: http://99designs.com/tech-blog/blog/2012/08/02/color-explorer/ http://99

I helped build a similar tool at 99designs. I blogged a bit about how we built it here: http://99designs.com/tech-blog/blog/2012/08/02/color-explorer/ http://99designs.com/tech-blog/blog/2012/08/02/color-explore... It uses R-trees to index colors in the Lab color space to do fast perceptual nearest neighbour color search. We open sourced the code behind it too, so you can implement search by color type features on your own set of images: https://github.com/99designs/colorific https://github.com/99designs/colorific - for extracting colors from images https://github.com/dhotson/colordb https://github.com/dhotson/colordb - for doing fast perceptual nearest neighbour color search