Abstract: In order to measure the driving characteristic of a piezoelectric actuator with high precision, a sub-pixel image block matching method of displacement measurement based on computer vision is proposed. Three important factors, including the searching region, the model size, and the fitting precision of sub-pixel, are analyzed and researched, and the most appropriate parameters are chosen with respect to both the experiment results and the measurement characteristic of micro/nano image sequences. The high-precision nano platform, the high power microscope and the standard grid are used together to validate the measurement precision of this method. The proposed method is used to measure the driving characteristic curve of a piezoelectric actuator practically. The experimental results of the piezoelectric actuator driving characteristic measurement are consistent with the physics analysis. Also, the proposed method, which is simple in manipulation and credible in measurement results, satisfies the requirement of high-precision micro/nano measurement.

Key words: Image block matching, Micro/nano manipulation, Piezoelectric actuator, Sub-pixel