Color Analytics
Some sample videos on YouTube:
These samples use 3D plots (histograms with "bubble" size representing the frequency of a color in the picture) in a bi-cone HSL color space - or as Wikipedia correctly states, rather in a Hue-Chroma-Lightness space. This way the distance between points reflects the human perception more closely. Not too close, unfortunately, recommended reading: CIELAB, color metamerism ...