Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Polychromatic Pixels

compoundsemiconductor.net

Post reply on HN
Print view View original

81–90 of 149 posts

Re: Polychromatic Pixels

#81

Post by lsaferite »

layer8 wrote: post #32
jjmarr wrote: post #16

My ultimate hope is that this will allow us to store and display color data as Fourier series. Right now we only represent colour as combinations of red, green, and blue, when a colour signal itself is really a combination of multiple "spectral" (pure) colour waves, which can be anything in the rainbow. Individually controllable microLEDs would change this entirely. We could visualize any color at will by combining t…

Color data has three components for the simple reason that the human eye has three different color receptors. You can change the coordinate system of that color space, but three components will remain the most parsimonious representation.

I started working with a hyperspectral imager a while back and the idea of storing image data in 3 wide bands seems so odd to me now. Just the fact that my HSI captures 25 distinct 4nm bands inside a single 100nm band of what we are used to with a 3-band image is awesome.

Sorry, I get excited every time I work with hyperspec stuff now and love talking about it to anyone that will listen.

Re: Polychromatic Pixels

#82

Post by Y_Y »

etrautmann wrote: post #70
jessriedel wrote: post #54

Earlier quoted context omitted.

Ha, yea, in particular these monochromatic pixels can't simply be white. Notably ctrl-f'ing for "white" gives zero results on this page. Relatedly, the page talks a lot about pixel density, but this confused me: if you swap each R, G, or B LED with an adjustable LED, you naively get a one-time 3x boost in pixel area density, which is a one-time sqrt(3)=1.73x boost in linear resolution. So I think density is really a…

It would be interesting to plot all of the achievable colors of this LED on the chromaticity diagram. Presumably it'd be some sort of circle/ellipse around white but might have some dropouts in certain parts of the spectrum?

Presumably they wouldn't need to do a pixel-to-pixel mapping, but could account for the wavelengths of neighbouring pixels to produce a more faithful colour reproduction at an effectively lower resolution.

Re: Polychromatic Pixels

#83

Post by thomassmith65 »

jmu1234567890 wrote: post #64
GrantMoyer wrote: post #45

A single wavelength can't reproduce all visible colors. These pixels are variable wavelength, but can only produce one at a time, so you'd still need at least 2 of these pixels to reproduce any visible color. The fundamental problem is that color space is 2D[1] (color + brightness is 3D, hence 3 subpixel on traditional displays), but monochromatic light has only 1 dimension to vary for color. [1]: https://en.wikipedi…

However, you would have more flexibility to do tricks sub-pixel to improve resolution?

Surely the 'tricks' we have for RGB displays would be more effective when every element has the same color range as every other. For example, the subpixel rendering of typography for RGB displays had an unavoidable rainbow halo that would no longer be an issue for most colors of text with polychromatic pixels.

Re: Polychromatic Pixels

#85

Post by meindnoch »

lsaferite wrote: post #81
layer8 wrote: post #32

Earlier quoted context omitted.

Color data has three components for the simple reason that the human eye has three different color receptors. You can change the coordinate system of that color space, but three components will remain the most parsimonious representation.

I started working with a hyperspectral imager a while back and the idea of storing image data in 3 wide bands seems so odd to me now. Just the fact that my HSI captures 25 distinct 4nm bands inside a single 100nm band of what we are used to with a 3-band image is awesome. Sorry, I get excited every time I work with hyperspec stuff now and love talking about it to anyone that will listen.

Hyperspectral imaging has its applications. A hyperspectral display on the other hand makes no sense (unless your target audience consists of mantis shrimps).

Re: Polychromatic Pixels

#86

Post by modeless »

mensetmanusman wrote: post #76
modeless wrote: post #49

I understand that one of the big issues with microLED is huge brightness variation between pixels. Due to some kind of uncontrollable (so far) variations in the manufacturing process, some pixels output 1/10 the light (or less) as others. Ultimately the brightness of the whole display is constrained by the least bright pixels because the rest have to be dimmed to match. Judging by their pictures they have not solved…

It is solvable with enough capital investment though, question is how much will it cost to solve.

Is it? I feel like there has already been a lot of capital investment by the various organizations working on microLED.

Re: Polychromatic Pixels

#87

Post by daniel_reetz »

jessriedel wrote: post #54
GrantMoyer wrote: post #45

A single wavelength can't reproduce all visible colors. These pixels are variable wavelength, but can only produce one at a time, so you'd still need at least 2 of these pixels to reproduce any visible color. The fundamental problem is that color space is 2D[1] (color + brightness is 3D, hence 3 subpixel on traditional displays), but monochromatic light has only 1 dimension to vary for color. [1]: https://en.wikipedi…

Ha, yea, in particular these monochromatic pixels can't simply be white. Notably ctrl-f'ing for "white" gives zero results on this page. Relatedly, the page talks a lot about pixel density, but this confused me: if you swap each R, G, or B LED with an adjustable LED, you naively get a one-time 3x boost in pixel area density, which is a one-time sqrt(3)=1.73x boost in linear resolution. So I think density is really a…

Don't forget about bond wires that need to be run to each die and/or connected to a backplane.

Re: Polychromatic Pixels

#88

Post by cubefox »

GrantMoyer wrote: post #45

A single wavelength can't reproduce all visible colors. These pixels are variable wavelength, but can only produce one at a time, so you'd still need at least 2 of these pixels to reproduce any visible color. The fundamental problem is that color space is 2D[1] (color + brightness is 3D, hence 3 subpixel on traditional displays), but monochromatic light has only 1 dimension to vary for color. [1]: https://en.wikipedi…

> These pixels are variable wavelength, but can only produce one at a time

Citation needed. The article doesn't say anything about how the colors are generated, and whether they can only produce one wavelength at a time.

Assuming they are indeed restricted to spectral colors, dithering could be used to increase the number of colors further. However, dithering needs at least 8 colors to cover the entire color space: red, green, blue, cyan, magenta, yellow, white, black. And two of those can't be produced using monochromatic light -- magenta and white. This would be a major problem.

Re: Polychromatic Pixels

#89

Post by ricardobeat »

daniel_reetz wrote: post #87
jessriedel wrote: post #54

Earlier quoted context omitted.

Ha, yea, in particular these monochromatic pixels can't simply be white. Notably ctrl-f'ing for "white" gives zero results on this page. Relatedly, the page talks a lot about pixel density, but this confused me: if you swap each R, G, or B LED with an adjustable LED, you naively get a one-time 3x boost in pixel area density, which is a one-time sqrt(3)=1.73x boost in linear resolution. So I think density is really a…

Don't forget about bond wires that need to be run to each die and/or connected to a backplane.

Doesn't the fact they have successfully demonstrated displays at 2000, 5000 and 10000 DPI alleviate those concerns a little bit?

Re: Polychromatic Pixels

#90

Post by FriedPickles »

lsaferite wrote: post #73
FriedPickles wrote: post #61

Earlier quoted context omitted.

An imager/camera: by illuminating a scene (or light box) solely with the tunable LED, sweeping it across the spectrum, and capturing it with an achromatic camera.

> achromatic camera Is that the same as a panchromatic camera? Edit: Asking because I have a 410x410px hyperspectral imager that has an aligned 1886x1886px panchromatic imager that is use to perform pan-sharpening of the HSI data bringing it up to 1886x1886. I'd never heard of a panchromatic camera before I got involved in this business and I've never heard of an achromatic camera either. All I seem to find is achrom…

Yes, "panchromatic" is probably the more accurate term for it. It's just a camera with no color filters and a known spectral response curve that's high enough across the frequencies being imaged.
Post reply on HN