zhengyuf/IMavatar

coordinate system

UestcJay opened this issue · 3 comments

UestcJay commented

hi, yufeng
In get_camera_params functions, the z is mul -1, I wonder if the camera and world coordinate system follow the OpenCV convention[right, down, forward]?

zhengyuf commented

Hey,

It probably doesn't follow OpenCV convention.
The z is not forward, but backward. x and y are probably right and down, but I'm not sure...
I just found a way that worked and I don't dare changing the camera system anymore.😂

Best,
Yufeng

UestcJay commented

thanks for your reply! sorry to bother you again. why the fx mul -1 in optimize.py here

zhengyuf commented

It's also multiplied by -1 in the saved intrinsics, so we made sure that the main code and preprocessing code have the same camera transformations.

As for why, there is not really a good reason, I think I just followed NerFace which also multiplied fx with -1, and just kept using this.