Verification of the FOV properties of HTC Vive Pro

[Jerry Pai]

Dear all,

I am currently working on a study regarding the magnification and minification of images in HMDs. I aim to achieve this effect by adjusting the rendered FOV, so I need to understand the initial FOV values of the HMD in order to check my scaling factor in the project.

The environment I am currently using is:

• HMD: HTC Vive Pro
• Application: Unity 2019.3.3f1
• SteamVR plugin: 2.8.0

I am currently using IVRSystem::GetProjectionRaw() to obtain the raw values of the view frustum, in order to calculate the FOV values. Below are my results.

Left eye

Right eye

Display

Vertical

Horizontal

Total

Stereo

tan_left

tan_right

tan_bot

tan_top

tan_left

tan_right

tan_bot

tan_top

Angle

FoV

FoV

Hor. FoV

Overlap

-1.349

1.202

-1.413

1.425

-1.205

1.349

-1.416

1.424

0.0°

109.7°

103.7°

106.9°

100.5°

However, there are some discrepancies between my results and the data I found on websites like Wikipedia and VRcompare. Their results are:

Horizontal: 107.06°
Vertical: 107.71°
Diagnol: 110.48°

https://en.wikipedia.org/wiki/List_of_virtual_reality_headsets#cite_note-fovnote-2
https://vr-compare.com/headset/htcvivepro
 

Therefore, I want to understand the physical and actual parameters of the HTC Vive Pro's horizontal, vertical, and diagonal FOV from the manufacture manual, to better understand what might be causing these differences.