Slashdot Mirror

for your clicking convenience...

The human is a blocked tetrachromat
Tetrachromacy

Some researchers think human's are "blocked tetrachromats". The fourth group of cones in this case is in the near ultra-violet, not refining green, yellow and red. Further, the lens of a normal human eye absorbs those UV wavelengths so strongly that the UV cones mostly see dark. Only when the lens is removed, as cataract surgery, are the UV cones activated.

I don't know how accepted this theory is, plus current physiology can't fully map the nerves of the retina to the brain.

From the samsung definition, it didn't seem to me that they were individually controlling the values of the sub-pixel colors. by this I mean: the four green pixels are probably still being excited from the same single driving line. What I think is different, is that the four green pixels are affected by their neighbouring pixels, and the hardware automatically does the anti-aliasing...

The article doesn't mention anywhere that they have increased the quality of the digital to analog signal converter precision of the LED drivers. It's using a standard RGB signal feed, so it can't be using a 0-2047 color range for the green.

Sorry, I know that wasn't clear.

http://www.photo.net/photo/edscott/vis00010.htm is a clear description of the eye. http://acept.la.asu.edu/PiN/rdg/color/color.shtml is another page that describes things as I have previously been taught them. I'm not sure which is right. Most literature seems to use a log scale, showing the eye to be less sensitive to blue than red or green. Such as: http://www.4colorvision.com/files/photopiceffic.ht m. I believe that we may be referring to different things. Blue cones are more efficient, and more sensitive to radiation than red or green cones, but red and green cones FAR outnumber blue cones. For this reason, we see blue as being less intense. http://www.cis.rit.edu/people/faculty/montag/vandp lite/pages/chap_9/ch9p1.html

One thing I find really interesting is that the eye is actually sensitive to the near-UV. We can see light below 400nm, as I have frequently experienced while teaching a spectroscopy lab. Students build their own Czerny-Turner spectrometer, and observe the emission bands from a mercury pen lamp. Some of the UV peaks are visible (not to all students), although very dimly due to our poor UV-response.

This is old news. Studies published in 2000 based on data from the early 90s have talked of the tetrachromat phenomenon. See this article. There is even a mention of it in wikipedia. Some people even think that all humans are blocked tetrachromats.

Temperature measured in F or C is an interval scale and thus percentage differences are not meaningful. But temperature measured in K is a ratio scale that is nice and linear and so it is entirely reasonable to measure percentage differences.

Similary, wavelegnth is also a ratio scale, simply distance per cycle. In other words, if it makes sense to talk about percentage difference between two distances then it makes just as much sense to talk about percentage difference between two wavelengths.

We use everything from radio waves to x-rays in appliances these days. With a dynamic range spanning so many orders of magnitude, how could it possibly make sense to talk about a percent difference? How about orders of magnitude different? I'm not saying it's mathematically impossible to have a percentage of a wavelength, but it's pointless.

Comparing the effects on life is just as meaningless, since anyone can pick any life, any range of wavelengths and any effects. Way too arbitrary for ~ to have any useful meaning either.

the eye moves (involuntarily) to make a smooth image out of a number of samples,

Where did you hear this? That isn't how the eye works at all.