<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>To satisfy the demands of the continuous zoom stereo microscope, a parfocality measurement method is proposed. First, the mechanical parameters of the focusing system are estimated by testing the highest and the lowest displacements of the lens group and the rotation angle of the knob simultaneously. Second, by analyzing images captured under different zoom rates, the relatively sharpest displacement under a specified zoom rate is obtained according to the values of the four definition functions, including the variance function, the gradient square function, the discrete Fourier transform function and the Walsh-Hadamard transform function. Then, an in-focus model is presented and implemented to determine whether or not the relatively sharpest displacement under a specified zoom rate is an in-focus displacement, and to obtain the discrete in-focus displacements under multirates. Finally, by using discrete in-focus displacements, a continuous zoom in-focus curve is fitted. Results from the experiments show that the proposed method can accurately and effectively measure the parfocality of a continuous zoom stereo microscope.</p></abstract>

To satisfy the demands of the continuous zoom stereo microscope, a parfocality measurement method is proposed. First, the mechanical parameters of the focusing system are estimated by testing the highest and the lowest displacements of the lens group and the rotation angle of the knob simultaneously. Second, by analyzing images captured under different zoom rates, the relatively sharpest displacement under a specified zoom rate is obtained according to the values of the four definition functions, including the variance function, the gradient square function, the discrete Fourier transform function and the Walsh-Hadamard transform function. Then, an in-focus model is presented and implemented to determine whether or not the relatively sharpest displacement under a specified zoom rate is an in-focus displacement, and to obtain the discrete in-focus displacements under multirates. Finally, by using discrete in-focus displacements, a continuous zoom in-focus curve is fitted. Results from the experiments show that the proposed method can accurately and effectively measure the parfocality of a continuous zoom stereo microscope.

A Parfocality Measurement Method of a Continuous Zoom Stereo Microscope

Ningnbo Institute of Technology Zhejiang University

International Journal on Smart Sensing and Intelligent Systems

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

{"article-title":"A Parfocality Measurement Method of a Continuous Zoom Stereo Microscope"}

To satisfy the demands of the continuous zoom stereo microscope, a parfocality measurement method is proposed. First, the mechanical parameters of the focusing...

A Parfocality Measurement Method of a Continuous Zoom Stereo Microscope

Published Online: Sep 05, 2013

Page range: 1419 - 1434

Received: Dec 30, 2012

Accepted: Jul 03, 2013

DOI: https://doi.org/10.21307/ijssis-2017-597

© 2013 Yigang Wang et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.