Method for determining the position of a reference point of a scanning device relative to an incremental scale, and a reference point shaper

摘要

The position of a reference point of a scanner relative to an incremental scale with marks arranged thereon with constant spacings is roughly determined based on the marks passed along the scale multiplied by the spacing of the marks, and finely determined by interpolation between the marks. The interpolation between the marks is made by determining the projection angles between the reference point and three marks adjacently arranged on the scale, and by calculating the coordinates of the reference point according to trigonometric functions.