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What's a light point?

The documentation says that the HL resolution is 1268 * 720 per eye. It also says that the hololens "light engines" produce 2.8 million light points. Another measurement is 2500 light points per radian, which is equivalent to 1 "radiant."

Light points, light engines and radiants are all new to me, though. Is there a paper somewhere that explains how these relate to standard units of measure like pixels or lumens?

James Ashley
VS 2017 v5.3.3, Unity 2017.3.0f3, MRTK 2017.1.2, W10 17063
Microsoft MVP, Freelance HoloLens/MR Developer
www.imaginativeuniversal.com

Best Answers

Answers

  • from what i understand is this. I could be dead wrong though:

    1 radian = 57.296 degrees
    1 radian = 206265”.806

    Since interference and diffraction are key to making a hologram, you would use the physics principle of super position (light point) to measure the wavelength to create the effect.

    Here is a reference for it.

    so, pretty much it's saying within in this view is 'X' amount of light points that be translated into 'Y' amount of objects.

  • james_ashleyjames_ashley ✭✭✭✭

    @cgallizzi,

    I don't think that answers the question but it's a really cool way of looking at it. HoloLens doesn't really use hologram technology, afaik (unless possibly they are somehow used in the wave guides). Holograms appear to just be a useful and easy to remember term for digital objects mixed in with the real world objects in front of the user.

    James Ashley
    VS 2017 v5.3.3, Unity 2017.3.0f3, MRTK 2017.1.2, W10 17063
    Microsoft MVP, Freelance HoloLens/MR Developer
    www.imaginativeuniversal.com

  • james_ashleyjames_ashley ✭✭✭✭
    edited March 2016

    Gotcha. I was having trouble understanding the way vanilla did the layout but it all makes sense now. Resolution = total # of light points emitted; HL Density = minimum number of light points per radian.

    Thank you so much, Ashraf! I'm very grateful for this.

    [I might have also messed up marking your answer as the "answer". sorry about that.]

    James Ashley
    VS 2017 v5.3.3, Unity 2017.3.0f3, MRTK 2017.1.2, W10 17063
    Microsoft MVP, Freelance HoloLens/MR Developer
    www.imaginativeuniversal.com

  • BryanBryan ✭✭✭

    @Ashraf_Michail said:
    We publish rendered pixel count and light point count separately because they are different counts which both contribute to hologram quality. HoloLens uses more light points than rendered pixels to produce a more accurate hologram projection.

    Very interesting. I was under the impression you were using something like a mini DLP for the display projection. Is that right (ex: with 3 colored light points per pixel per eye)? Or is this multiple light points per pixel part of an entirely new display technology? I'd love to hear more about how this works.

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