Rolling shutter artifacts are caused by camera sensors reading lines sequentially instead of simultaneously (global shutter). With the correct settings, Gyroflow is capable of correcting for rolling shutter artifacts.
Frame readout time determination
There are multiple ways of determining the frame readout time. One approach is by recording a rapidly flashing source of light with a known frequency or pulse width, and analyzing the resulting image. For a known pulse width, the size of the bands can be used in order to find the frame readout time. For a known frequency, the number of bands can be counted. Using LED's for rolling shutter measurements is described in this blog post: https://joancharmant.com/blog/measuring-rolling-shutter-with-a-strobing-led/