Error analysis and compensation of linear structured light scanning probes

For polynomial fitting measuring model of a linear structured light scanning probe, the extraction and compensation methods for systematic errors of the probe are presented. By measuring fixed lines at different height, the proposed method extracts the measuring errors in positions with different depth of the field. And systematic errors of the probe at different measuring height are separated from the extracted errors, and the first error compensation in the height direction can be implemented. According to the calibrating result and error compensation lattice in the height direction, a comparison is made between the spatial lattice obtained by calibrating image grid lattice and the practical calibrating spatial grid lattice. The remaining errors of measuring results after compensation in the height direction are further extracted. And the second error compensation and correction are implemented simultaneously. The experimental results show that the measuring depth of field can be expanded effectively and reached 150 mm with the presented method. A high accuracy (±50 μm) can be ensured in a large range of depth of field on common mechanical accuracy platforms (single axis positioning accuracy: 15 μm) driven by step motor with open-loop style.