Lateral error compensation for stitching-free measurement with focus variation microscopy

This paper proposes a practical methodology to quantify and compensate lateral errors for focus variation microscopy measurements without stitching. The main advantages of this new methodology are its fast and simple implementation using any uncalibrated artefact. The methodology is applied by performing measurements with multiple image fields with and without stitching on an uncalibrated artefact and using the stitched measurements as reference. To quantify the lateral errors, the determination of their geometrical components is carried out through kinematic modelling. With the quantified errors, compensation can be applied for lateral measurements without stitching. Over the entire 200 mm lateral range, the lateral errors without stitching and without compensation can reach up to 180 µm. With the proposed error compensation methodology, the lateral errors have been reduced to around 15 µm. The proposed methodology can be applied to any Cartesian-based optical measuring instrument.