The question when calculating focal_pixel

[Xin-97]

Hi @szymanowiczs,

Thanks for your great work. I am a new one in this field. I found a formula for focal_length to focal_pixel, F(mm) = F(pixels) * SensorWidth(mm) / ImageWidth (pixel). When you calculate focal_pixel here

splatter-image/scene/dataset_readers.py

Line 114 in a2cbd6d

focal_lengths_px = focal_lengths_ndc * image_side / 2

Why you set sensorwidth to 2? Thanks!

[StellarCheng]

Thanks for your work! And I also wonder how to find some parameters in the configs too.

[szymanowiczs]

Hi @Xin-97 this is because CO3D cameras are in NDC coordinates: see bottom of the page here. https://pytorch3d.org/docs/cameras.