Detailed parameters of cameras when generating renders results from Objaverse about zero123

[ruoshiliu]

Hi @ZexinHe , fov is the same thing as camera_angle_x in NeRF's blender dataset, which is 49.1 degree or 0.857 rad as stated in the appendix section of the paper. I might be wrong but I think rotation is not part of the camera intrinsics for NeRF. It describes the rotation angle between two consecutive viewpoints.

[ZexinHe]

Thanks for your timely feedback! I've found the details now. And you are right about rotation, the information is contained in the sequence of transformation matrices.

[yjcaimeow]

Hi @ZexinHe , So，I want to make sure whether right using the following equations to obtain the intrinsic K for objaverse dataset ?

H, W = imgs[0].shape[:2]
camera_angle_x = float(meta['camera_angle_x'])
f = 1 / np.tan(camera_angle_x / 2) * (W / 2)

Best,
Ying

[ZexinHe]

Hi @yjcaimeow ,

I think you are correct. The above code obtains the focus, which leads to the intrinsic K matrix.
K=[[f,0,W/2], [0,f,H/2], [0,0,1]]

Bests,
Zexin