Optical profilometers perform an axial scan of an object to reconstruct its height map. Since the positioning errors of the scanner are directly transferred to the measurement, it is essential to minimize them. We present a zero-cost solution to suppress such errors, based on the computational analysis of two topographies that are identical except for an axial shift. The approach iteratively computes the a priori unknown nonlinearity operation of the scanner until the differences between the two corrected topographies are consistent. Here, we propose a new method for obtaining the topography pair. We use illumination from different LEDs, thereby exploiting the longitudinal chromatic aberration of the optical system to generate the axial shift. Interestingly, since only electronic switching of the LEDs is required, the approach enables to acquire the pair of topographies with a single scan. The method yields results comparable to measurements performed with a high-quality piezoelectric-based scanning system.
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