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Mixed reality inaccuracy
I'm not using mixed reality, but have created something similar. So I have a uwp Unity app that is getting the pose and rotation information from the hololens and overlaying the video feed from the hololens over the unity world. The only problem is when I create a hologram annotation based off of a ray cast, the annotation in not in the same place on both the hololens and uwp app. I am able to calibrate using the frustum, field of view, and aspect ratio settings, but it seems like the calibration will only work for one distance. Trying to place the annotation on anything closer or farther than that distance will result in inaccuracy. Is it possible to account for this in some other way? Also the field of view for the main camera in the UWP app I'm using is 25 degrees, but the docs say that the physical camera has a 45-degree fov. What could be the reason for that discrepancy?
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Figured it out, had to move the camera's Z position up .03925 since the camera is above the eyes. So when I would try to place something based on what the camera was seeing, it was actually a slightly elevated view from what the wearer's perspective was. After that is accounted for, just needed to adjust the frustum to right dimensions so that the annotations are accurate.
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How do you get the pose and rotation information from the hololens? If you're creating a frame of reference, the frame itself generates a new set of coordinates. Meaning, wherever you create it, it will be 0,0,0 and whatever pose you get after moving, is relating to that frame.
Also, one thing I've noticed, is that the coordinates from a frame in the real world, if you do one step foward, the Z goes negative, while in Unity3D the Z goes positive.
I'm not sure I understand your issues, maybe if you explain a bit more. But I'm giving these notes to maybe help out a bit.
www.irisprime.com
my linkedin here
@Palma I'm getting the position and rotation information by getting the transform information, breaking down into its parts, and sending them over a datastream as bytes which are then read in by the UWP app so they have the same position info. I don't have any problem with that necessarily, but there seems to be an issue with where each side is rendering the annotation that I create.
@hereswilson
With HoloLens, we enjoy unintentionally our stereo-view ability in front of the two (left & right) display panels of HoloLens. But, the views (displays) of HoloLens are fixed at 2 m from the center of projection (COP), eventhough the disparity of our eyeballs are not fixed and varying unintentionally.
@CurvSurf so what I'm trying to do is not possible because the displays are fixed at 2m, but the distance that I place holograms at are different than 2 meters? I don't think this is my problem though. The hololens is going to place the hologram in the "correct" position I just want to be able to mirror what the hololens is seeing on the video side so when I click on the video to place a hologram I don't miss.
I think it might have something to do with the parallax between the eyes and the camera.
@hereswilson
'Hologram stability'
https://developer.microsoft.com/en-us/windows/holographic/hologram_stability#hologram_render_distances
Section 'Hologram render distances'
Figured it out, had to move the camera's Z position up .03925 since the camera is above the eyes. So when I would try to place something based on what the camera was seeing, it was actually a slightly elevated view from what the wearer's perspective was. After that is accounted for, just needed to adjust the frustum to right dimensions so that the annotations are accurate.
How did you compute this value? I have exactly the same issue. I would like to comprehend this in detail. Thank you very much.
Hello hereswilson
I have the same problem.
How did you solve it?