Color blindness simulation

[Medium]

Since this is subject to individual perception, and color blindness exists in varying degrees and "flavors", I would assume, that there can not be any "general" simulation algorithm. I would even go so far to say, that it would be impossible to simulate, because a color blind person would not be able to say, if he sees red as green or green as red (for example), since this person has no concept of red or green, and thus cannot put a "compatible" name to the perceieved sensation when presented with these colors.
If anything, you could attempt to give a conceptual impression of how a color blind person "feels" a picture when looking at it, by hue-shifting the respective colors closer to each other. But even then there is the variability in colors and strength of the blindness that needs to be addressed, and the resulting image merely would depict to a normal sighted person how good or bad a person with this particular form of simulated color blindness would be able to make out contrasts. But not at all how he would actually "see" it.

Thus, this problem becomes mildly complex, and rather useless atop of that, because it may never do more than serve illustrative purposes. Would that be worth your hassle?