Mind-blowing, eh?
January 28th 2004 -
Mind-blowing, eh?
I think this is probably the best optical illusion I’ve ever seen. We had an excellent talk on colour perception today, in a lunchtime seminar. Completely mind-blowing, especially the bits about metamerism.
The problem goes a bit like this. We’ve got very limited colour vision, obviously. We don’t see into the infra-red or ultra-violet. But it goes further than that. We’ve got sensors for red, green and blue in the cones in our retinas, and different mixes of that allow us to perceive a whole bunch of colours.
The objects that we see usually reflect/emit a very wide spectrum of light, with different frequencies emitting at different intensities. Essentially, our take on the colour of the object is done with a three-point sample. We miss a lot of the complexity of the true “colour”.
What this means, is that you can have two objects that reflect wildly different spectra, that will, none the less, appear as exactly the same colour to us because of the sampling errors of our eyes. This is called metamerism. It’s only really a factor when you create a representation of that colour – for example, a painting, a photo, or an image on a screen. To us, it looks like a good representation of the original object, but in fact, it’s lousy – it would look ridiculously wrong to someone who had, say, four or five colour receptors in their eyes (even if their colour sensors didn’t extend into UV or IR) instead of the three we have.
Apparently, various armies made use of this during wartime. Camouflage works because the object appears the be the same colour as the surroundings, to our limited colour senses. Some people are born with slightly different pigments in their eyes, and so have different “sampling points” for their colour recognition. To them, the camouflage tuned to our eyes looks completely obviously out of place.
This may be old-hat to y’all, but I don’t recall being taught this in high-school. I’m still a bit stunned.
David Carroll Says:
January 29th, 2004 at 12:17 pm
"But it does move…"
Andrew Says:
January 29th, 2004 at 2:44 pm
As an interesting follow-up, here’s a link that indicates some new ways that vision can be improved.
ChrisT Says:
January 29th, 2004 at 2:57 pm
If you use that image as wallpaper on your desktop people stop and talk to you.
baddogbot Says:
January 29th, 2004 at 9:51 pm
yes, that’s true. revolutionary otaku linbot sent me a copy of it a couple of months ago, & being in something of a (how you say?) bad mood with some of my cow-orkers, i went the whole squinty/queasy desktop route. i found that when people did stop to talk to me, the conversation usually followed the following format:
cow-orker: hey, what’s that?
me: what does it look like?
cow-orker: what *is* it?
me: my new desktop image.
cow-orker: it moves.
me: yes.
cow-orker: does it really move?
me: does it *look* like it moves?
cow-orker [squinting]: woah.
me: i am the angel of death…
of course, your mileage may vary…