Is an angular standard necessary for rotary encoders

TLDR: SelfA as mentioned in this paper is a self-calibratable angle device that can detect a variety of angle deviation sources by itself, and has the ability to output an angular calibration value.

Abstract: A rotary encoder is an angular readout device that reads an optical pattern written on the circumference of a shaft similar to a 360 degrees protractor and outputs angle position information. Since the output of a rotary encoder deviates from the true angle position due to optical pattern errors or eccentricity of the shaft about the rotation axis, users have encountered difficulty in ensuring the reliability of the angle information derived from an encoder. In order to solve this problem, "SelfA: A Self-calibratable Angle device" was developed. The SelfA can detect a variety of angle deviation sources by itself, and has the ability to output an angular calibration value. This SelfA can detect the angle deviation value from an optical encoder which has been a black box until now and enables "visualization" of these factors quantitatively.