Small-size, high-resolution angular displacement measurement technology based on an imaging detector.

It is challenging to design a photoelectric encoder that is small in size while ensuring it has sufficiently high resolution and accuracy. Traditional displacement measurement via the moiré fringe signal does not facilitate high resolution at small grate sizes; photoelectric and digital photo processing can significantly improve the angle measurement resolution over traditional techniques. The primary focus of this paper includes grating displacement coding and decoding, as well as the corresponding high-resolution subdivision and measurement error factors. A small-size absolute photographic encoder was designed (50 mm diameter) that exhibits resolution of 1.24^'' (20 bit) with a standard deviation of error of 14.3^''. The results presented here may provide a theoretical and technological foundation for further research on small-size, high-resolution photographic rotary encoders.