Dan Kaminsky’s iPhone/Android app corrects for color blindness (in anomalous trichromats anyway)…just point your phone at what you want to see in color and make a few adjustments.

The vast majority of color blind people are in fact what are known as anomalous trichromats. They still have three photoreceptors, but the ‘green’ receptor is shifted a bit towards red. The effect is subtle: Certain reds might look like they were green, and certain greens might look like they were red.

Thus the question: Was it possible to convert all reds to a one true red, and all greens to a one true green?

The answer: Yes, given an appropriate colorspace.