VERNIER: an open-source library pushing marker pose estimation to nanometric resolutions

At the small scales, few solutions exist to capture the pose of an object with nanometric and microradian resolutions over relatively large ranges.Over the years, we have proposed several fiducial marker and pattern designs to achieve reliable performance for various microscopy applications.VERNIER is an open source phase processing library designed to provide accurate pose measurement based on these results.Centimeter ranges are possible using binary encoding methods, while nanometer resolutions can be achieved using phase processing of the periodic patterns.Moreover, the detection has proven to be particularly robust to noise, defocus and occlusion thanks to a local thresholding algorithm based on the phase.The paper presents the measurement principles and the patterns implemented in VERNIER addressing different application needs.