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Spatial Mapping In The Dark

Hey guys, so I recently decided to try to make a HoloLens version of the popular horror game Slender since I feel that'd be a perfect way to play that game. However, this is a game that's best played in the dark. The problem is, when I tested the game, I discovered that in the darkness, even semi darkness, the HoloLens spatial mapping does not work. It can't seem to detect anything at all and as a result none of my games or apps will function because it will keep attempting to search for the environment around me. Just wondering if this is a definite limitation of the HoloLens or if there's a way around this?

Answers

  • I'm pretty sure this is a definite limitation of HoloLens. It needs at least some light in order to map the world. I've tried this as well using a light that can be dimmed and we were able to get the light to be pretty dim/low and still have spatial mapping capabilities. But once we went past a certain threshold (to almost completely dark), then the spatial mapping just failed.

  • Jarrod1937Jarrod1937 ✭✭✭
    edited August 2016

    It uses infrared for spatial mapping but visible light for the position/object/anchor tracking. Only way to make this better would be for them to use more sensitive cameras (CCD I assume is what they're currently using) or a longer exposure time, which may be difficult to stabilize with the head jitter and rapid motion associated with it's use. Originally I was thinking they could use different bands within the infrared spectrum, one for spatial and the other for tracking. However, different materials react differently to infrared, so it may not work well for anchor tracking. I'd also assume they're probably using a wide band already for the spatial mapping to aid in noise rejection from ambient sources. I'd be interested in talking to an engineer here, the tech is interesting, but not sure if they'd be allowed :-\

  • @holoben said:
    I'm pretty sure this is a definite limitation of HoloLens. It needs at least some light in order to map the world. I've tried this as well using a light that can be dimmed and we were able to get the light to be pretty dim/low and still have spatial mapping capabilities. But once we went past a certain threshold (to almost completely dark), then the spatial mapping just failed.

    I tried using a flashlight in a dark room, but it wasn't good enough either.

    @Jarrod1937 said:
    It uses infrared for spatial mapping but visible light for the position/object/anchor tracking. Only way to make this better would be for them to use more sensitive cameras (CCD I assume is what they're currently using) or a longer exposure time, which may be difficult to stabilize with the head jitter and rapid motion associated with it's use. Originally I was thinking they could use different bands within the infrared spectrum, one for spatial and the other for tracking. However, different materials react differently to infrared, so it may not work well for anchor tracking. I'd also assume they're probably using a wide band already for the spatial mapping to aid in noise rejection from ambient sources. I'd be interested in talking to an engineer here, the tech is interesting, but not sure if they'd be allowed :-\

    Do you suppose there's a way to run an app without spatial mapping or any of the tracking features? I know you can run the HoloLens in a "Limited Mode" but which ignores spatial mapping, but as soon as I start up a game, it returns to standard mode and tries to map my surroundings.

  • If the specific application requires spatial mapping, not sure what you could do. Even if you could force it to work, the fact that it was designed with spatial mapping in mind means it wouldn't operate properly.

  • I tried following those instructions to manually handle tracking loss, but I can't uncheck the display tracking loss image option. It's all greyed out for me in the settings panel.

  • You could market your app with special 'light points' kind of like the HTC Vive, that would help the HoloLens know what area the app is played within.

    Alternatively, you could try making the actual app be darker inside of Unity itself.
    With the limited FoV, the experience would be similar to that of HoloTour.
    :smile:

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