Sunday, October 19, 2014

Project update 1

My project in AP 186 knowing how good is the color display if you use quantum dots as your light-emitting devices instead of light-emitting diodes, or other devices.

How can I know how good is a color display? This is when the CIE xy chromaticity coordinates come through.

So first, how does the eye perceive color? We know that our color primaries (red, green, blue) can form a color and a mixture of this is a color pixel in a color display like a TV. The CIE color matching functions are like the spectral sensitivity of the eye to the color primaries. It is because they are derived from a human observer.

To do this I need to plot an CIE xy chromaticity diagram.
So I used these equations:

where K is a normalizing function, P is the power distribution of some object Q, and X,Y,Z are the color matching functions that I downloaded from the web. The power distribution that I used is the dirac delta function for every monochromatic wavelength from 380 nm to 780 nm with increments of 5nm. This is so that I can form the bounds of the CIE xy chromaticity diagram. [1]

Now you can get the CIE xy chromaticity coordinates using these equations[1]:



and 


I already have plotted the CIE color matching functions, and using Scilab and it is shown below.


And I plottted the CIE xy chromaticity diagram using equations 1-5.



Figure 1. Computed CIE xy tongue.

Figure 2. Reference CIE xy tongue from Wikipedia.org
Now I need to do the measuring the Gamut of color displays, so I can see if quantum dots as color display is better than an LED display.


References:
[1]J.Soriano, AP 186 manual - CIE xy Chromaticity Diagrams 2010, 2014.

[2]CIE 1931 color space, http://en.wikipedia.org/wiki/CIE_1931_color_space

For CIE xy tongue comparison map:
[3] http://upload.wikimedia.org/wikipedia/commons/thumb/3/3b/CIE1931xy_blank.svg/450px-CIE1931xy_blank.svg.png

For colloidal quantum dots:
[4] http://www.nano-reviews.net/index.php/nano/article/view/5202/5767#F0003

For the CIE's color matching functions:
[5] http://www.cvrl.org/cmfs.htm

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