Idle thought:

[cdave]

Colour is (badly) defined as the relative amount of one three frequencies of light waves reflected off a visible point.

Could you make a false colour ultrasound image by using three different frequencies of ultrasound? If so would they be of any use?

Comments

[cdave]

That's not right. Our vision receptors are rods and cones, and one of them (never can remember which) is responsible for night vision, and is essentially monochromatic.

You can see in 2D, because you have a 2D retina. You can see in 3D because you have binocular vision and ... hang on. This is a metaphorical dimensions of colour isn't it?

Hmm. Interesting. Talking to someone who has gone colour blind later in life is the only test I can think of.

[andrewducker]

Yes, metaphorical dimensions :->

[idaho-smith.livejournal.com]

Yes to bell-curves for sensitvity vs. wavelength for each of the colour dependant chemicals "opsins".

_C_ones for _C_olour

_R_ods for ... erm ... _R_unning about in the woods at night without a gamekeeper seeing your torch.