High Speed and Large Effective Range Autofocusing based on Numerical Wavefront Propagation

摘要

Autofocusing is widely used in microscopy since it provides sample details with high resolution and contrast. However, massive image recording along optical axis is often indispensable in classical autofocusing tactics, obviously decreasing autofocusing speed. To increase processing efficiency, we propose numerical wavefront propagation based autofocusing with high speed and large effective range. Firstly, quantitative sample phase is retrieved from multi-focal images according to transport of intensity equation with Gerchberg-Saxton algorithm. Then, various intensities along optical axis are numerically computed via wavefront propagation, thus focal position can be determined according to in-focus criterion. Finally, in-focus image is recorded via sample stage shifting. Since the proposed autofocusing approach can be easily integrated into commercial microscopes, additionally, it considerably reduces image captures as well as time consuming, we believe it can be adopted for rapid autofocusing in microscope.