Rotation representation

[zhangy76]

Hi,

Thank you for presenting this intereting work!

I notice the output of your model is in axis-angle representation. I wonder how did you convert them to Azimuth, Pitch, and Roll and impose the feasible range loss?

[TerenceCYJ]

Hi.

In our experiments, we directly use MANO's pose parameters as Azimuth, Pitch, and Roll.

[zhangy76]

Thanks for the reply! May I ask where did you define the Azimuth, Pitch, and Roll parameters in the code?

[TerenceCYJ]

Please refer to examples/losses.py#L143, examples/traineval_util.py#L378 and examples/utils/freihandnet.py#L208.

[zhangy76]

Thanks. Could you please also point out where you define the function to compute the rotation matrix using Azimuth, Pitch, and Roll? Since I only find a "rodrigues" function, I am confused about the rotation representation.

[TerenceCYJ]

Please also refer to examples/utils/hand_3d_model.py#L59.

[zhangy76]

examples/utils/hand_3d_model.py#L59 tries to obtain 3D hand mesh given hand model parameters. In this part, the only function to compute rotation matrix given hand pose parameters is "rodrigues", which computes rotation matrix from axis-angle pose parameters but not Azimuth, Pitch, and Roll. I wonder if my understanding is correct?