Focal length has 2 values

[ehedlin]

Hey, I have a question about cameras.h5. Each camera seems to have 2 focal lengths (shape 2x1). All other entries seem to make sense to me (translation is a 3x1, rotation matrix is a 3x3x1, etc). Which is the right value or is there something I am missing?

[una-dinosauria]

Great catch! Apparently our documentation is wrong 😅

They are both right. Often the x and y components of the focal length can differ due to a number of reasons; eg from http://ksimek.github.io/2013/08/13/intrinsic/

• Flaws in the digital camera sensor.
• The image has been non-uniformly scaled in post-processing.
• The camera's lens introduces unintentional distortion.
• The camera uses an anamorphic format, where the lens compresses a widescreen scene into a standard-sized sensor.
• Errors in camera calibration.

I'll be very thankful if you submit a PR correcting the documentation.