In measurement technology and metrology, calibration is the comparison of measurement values delivered by a device under test with those of a calibration standard of known accuracy.

У меня как-то так работает: mat3 calibration_rotation_matrix_from_gravity(vec3 gravity) { /*.

Calibration Cards expire after 2 years from the date of issue. Either of them will allow you to calibrate the reflectance levels which is what calibration does.