Correcting Color Blindness With DLP Projectors

About five percent of the population is colorblind to one degree or another, and for them seeing the entire spectrum from Roy to Biv is simply impossible. Their eyes simply don’t have the cones to detect certain colors. The brain is the weirdest machine on the planet, though, and with the right tricks of light, even the colorblind can see more colors than they’re accustomed to. That’s the idea behind [PointyOintment]’s entry for the 2016 Hackaday Prize: color blindness correcting goggles.

Any device that claims to correct color blindness comes with a few caveats and a slightly loose interpretation of what ‘color blindness correcting’ actually is. For the same reason you can’t see deep infrared, someone with color blindness cannot distinguish between two colors; the eye simply doesn’t have the sensors to see a specific color of light. This doesn’t mean the ability to distinguish color in color blind individuals can’t be improved, though. The EnChroma glasses use an optical notch filter to block all colors between blue and green, and between green and red. This works, because the human brain is weird enough and can adapt to nearly anything.

[PointyOintmen] isn’t going with an optical notch filter. He’s using spinning color discs from a DLP projector and 3D ‘shutter’ glasses to present the world in different shades of color many times a second. It’s weird, untested, and will take a few hours to get used to, but it is a very interesting idea. Will it allow color blind people to see more colors? That’s a semantic issue, but if you define ‘seeing color’ as being able to differentiate between two different colors, yes, it will.

49 thoughts on “Correcting Color Blindness With DLP Projectors

        1. Yes , saw that.

          in 24 bit the common notation is #FF0000

          but in most other systems it is 16 bit with a different number of bits per color and the opposite order

          so more like 0x003F

    1. Red can be defined as the visible color we see when the wavelength is nominally between 620-750nm. Wavelength can also be interpreted as Energy (thanks Quantum mechanics), and corresponds to the energy range 1.65–2.00 eV. (Blue is 450–495 nm or 2.50–2.75 eV).
      So Red is anything emitting energy (its always photons) in the range of 1.65–2.00 eV (That’s electron Volts).

    2. It depends. I’m pretty badly colorblind with RGB, and playing video games like FIFA definitely shows. For me, when a color I cannot see is displayed, my interpretation will depend on the surrounding colors. Sometimes red will show up as a bluish purple, or even become grey. Other times, it just blends in with the surrounding colors and is hard to distinguish. It’s pretty confusing stuff, and can make multiplayer gaming very difficult :/

  1. I’m curious if you could correct color blindness with an *extremely* accurate vr display, accurate enough to paint individual cones. Once you are able to do that, select a subset of cones to be artificially sensitive to a given color.

    1. You wouldn’t be able to align it.

      In any case color blindness if just a different sensitivities to specific frequencies of light, You can increase the brigness of some colors and decrease others to correct the vision at the expense of contrast.

  2. I think a relate-able idea is that we’ve all seen false color images of various things, such as the output of an IR camera. It seems eminently doable to digitally image the scene and based on the viewer’s particular form of color blindness, remap the color space into tones which are distinguishable. Doing it with purely opto-mechanical means seems a lot trickier.

    1. As I understand it, the problem is one of dynamic range, it’s like colour blind people (me included!) can only see in good ‘ol 8bit colour. I can tell 0xFF000 from 0x00FF00, but there are shades in the middle that I just can’t distinguish.

  3. I speak as one of color blindness. I usually defer to the term “deficiency” instead of “blindness” because that is when you get to people thinking you do not see a color whatsoever. The vast majority who have the genetic anomaly have an insensitivity to a portion of the color spectrum causing color discernment problems, that is, it is difficult or impossible to distinguish between between shades of similar colors. It is rare amongst this group of people where they are completely missing a S, M, or L cone, which is what they article states.

    I do want to say that despite this, life in a field affected by such a genetic trait isn’t impossible. I’m a supervisor in a photography department of over 450 individuals. I an the go-to guy for correcting any of our locations’ color balance, gelling the on-camera strobes, determining correct exposure, and dealing with our low-light locations. Knowing color additive systems, understanding a bit about the human vision system, how the human eye differs from a CMOS/CCD sensor, et al, help with this.

    I’m curious about this project, though simply put, I’ll be surprised if it aids in the complex form of color correction of photography as that would be a true test of it’s ability to do what is claimed.

    1. This reminds me of when I worked for a guy with similar vision to your own. He could look at a row of fluorescent lights and tell me precisely which ones needed changing because their color was way off to his eyes. Apparently, the slight color change of a dying lamp, which is all but invisible to my better-than 20/20 vision, was obvious to him.

      Thanks for sharing your story.

      1. Weaknesses cause other strengths.

        For example, in our man-made world there is a very limited number of colors (nature has them all). Cars for example have only been manufactured with a very limited range of colors so for those who are color blind it is even a narrower range of shades. I can see a car so far away that you can’t tell what it is and I can tell you the make model and year-range in many cases (there are exceptions) because of it’s shade.

        Resistor color codes are arranged into shades. This worked well in the era of carbon resistors but the standard was abandoned when China started exporting metal film resistors.

        Color coded wires (pairs) that have dashed strips are also encoded by the length of the dashes.

        As [DainBramage] there are other advantages. At home I use a 5700 degrees kelvin light so that I can see more of the colors that others see.

        Another point is that color blind people generally have a far greater understanding of color than normal color perception people because normal color perception people take color for granted.

        #FF0000, #FFFFFF and #0000FF, the girls love you etc (ancient rhyme)

        Color blind people were used as spotters in WW2 to see the enemy from aircraft because color blind people are not confused by camouflage.

        It may also interest you to know that colors don’t actually exist outside of your brain. See that RED pen on your desk … wrong , there is no such thing as RED in the real world. You call it RED because you have been taught to associate the perception your brain creates as RED. If you were taught that it is BLUE then you would call it BLUE. You have absolutely no idea of what the perceived color is, except what you have been taught.

        I expect a few bites on that last point lol.

    2. “…the eye simply doesn’t have the sensors to see a specific color of light.”

      That’s not strictly true. The sensors are broadband, they sense only the presence or absence of light. It’s the filters in front of the sensors that are the problem. One or more of the filters is not correct. Think of an RGB sensor, now imagine what would happen if, say, the filters over the R and G sensors were both the same color.

      // color blind, or, as I like to say, “chromatically challenged”

    1. I didn’t know that these could shatter in use. Do you think the lower operation temperature in my application would make it less likely? Regardless, I’ll add some shielding to the prototypes, and my future custom filter wheels will likely be made of some kind of shatterproof plastic.

  4. Might want to add some protection to the exposed color wheels but otherwise excellent idea! I had an idea a while back for a modified DLP projector that projects RGBCY to give a better image for certain applications.
    The big problem is likely to be rainbow artifacts due to the slow refresh rate however, this is why I never pursued it.

    1. The wheels I have right now are actually RGBCMY; a project log post addressing this will be posted soon.

      Rainbow artifacts could be problem, depending on how the brain combines the images, though the wearer might have to move their head slowly anyway due to the wheels acting as gyroscopes (at least until I make custom ones that can counter-rotate).

    2. I dunno, they’ve got some decent refresh rates now on DLP projectors. Re-programming it to support the extra colours would be a bugger, simple-ish in theory, but the hardware details and keeping it all synced would be a bit of a nightmare without original source code.

      Do you think it’d make much of a perceptible difference? We still only have 3 colour cones in our eyes. I heard some TVs, from Sony or somebody, use yellow pixels.

  5. I’m affected of Deuteranomaly, if there is some=thing I hate are the colour coded resistors.

    Anyway, I read around about a gene therapy in experimenting, I don’t think that smart glasses can give me a better colour feeling, just reduce the wole spectrum.

    1. We had an electronics instructor in high school that was always asking students what value a resistor was…

      We thought it was a pop quiz thing, but it turns out he was color blind and could not read the code. ;)

  6. In a way, having only finite number of colour-sensitive molecules, and our vision covering only a narrow band of EM spectrum, we all are more or less colour-blind. A generalized solution for the problem would empower everyone.

  7. It’s a little know fact that people who have perfect color vision are less common than those who have normal vision and in that context – all but a small few are to some degree – color blind.

    1. I remember reading a book on colour vision. The author stated that if you can see yellow on an RGB display, you are colourblind.

      Basically, everyone is colourblind – depending on how you choose to define colourblind. For the most basic version, those with a deficiency in any of the red green or blue cones are colourblind. However, in a more general sense – the ability to “correctly” discern any colour – we are all colourblind. Under the right conditions, almost any colour can be incorrectly interpreted. Colour doesn’t exist in the real world – it exists in the brain; it’s how we interpret the light energy. The brain can be fooled in many ways.

  8. “About five percent of the population” should read – 10% of men (almost no women are affected by this).
    Doing an online Ishihara colour test will tell you if you are at all colour deficient, but is not an accurate gauge of how bad. See an optometrist for more info.

    1. “Population” refers to both men and women, males and females.
      And it is the number, the quantity within a population, what counts

      Think about it: around 50% of the population are males and about around 50% are females …
      What extra value you get stating: “100% of males are males …”

      1. No lol, 100% of males are not males for the purpose of this question because for some – they’re dead! Males die at a higher rate at every stage of life so there are NOT 50% males and %50 females.

  9. There is existing technology doing this from Enchroma (http://enchroma.com/). According to their site it is not ‘blindness’ but a variation in the ability to differentiate blue, red and green. Their lens introduce notch filters so the eyes can clearly differentiate the colors. See their site for the details because I’ve probably muddled it a bit.

    I’ve been tempted to get a pair of their glasses but their test indicates the glasses may not help my situation.

    What I’d like to see is a smartphone app that provides the same notch filters. I suggested this to them as a way of determining if their lenses will work for a purchaser. Similarly, I know there are apps that will change the colors in a browser so why not apply the notch filters… especially on hackaday.io .

    1. Both my project description and this blog post mention EnChroma. However, as you found, their product doesn’t work for everyone. Mine should, I hope.

      The problem I see with a smartphone app like you describe is that each subpixel of the screen emits certain wavelengths that cannot be altered in software. For that to be possible, it would need to be a hyperspectral display, which I don’t think exists. (Same goes for the wavelengths sensed by the camera.) Therefore, a screen cannot simulate a notch filter’s actual effect, only what it might look like to a person with a particular kind of color blindness. (It’s related to how the color rendering index of lighting works, I suppose.) You might be able to achieve the desired effect by adding a notch filter layer to the LCD/OLED stack, or by tuning the red and green subpixels’ wavelengths.

      A similar idea is a smartphone app that maps wavelengths that the camera can see to ones that you can see. That would work, I think, but would not have exactly the same effect. It would instead show one or two colors at a time, and tell you which ones, letting your brain combine them into full color, like my goggles will.

    1. Exactly. The question really comes to, how long until this is available, and what will the cost be?
      I feel it necessary to point out, though, that I haven’t heard of anyone DIYing gene therapy…
      While we’re at it though, I seem to recall mantis shrimp… 16 colors, multispectral, tunable, polar… Though no infrared…

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