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| An Auto-focusing Algorithm of Cross-line Target Based on MTF |
| WANG Li-gang,DING Xiang,HONG Bao-yu,LI Fei |
| National Institute of Metrology, Beijing 100029, China |
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Abstract The cross-line target is the common target in focusing systems. Its focusing accuracy is the key factor affecting measurement results. The traditional focusing function cant fully meet the requirements in terms of sensitivity and real-time performances. The focusing curve is drawn by continuously measuring MTF values of multiple images at fixed frequencies with the automatic focusing evaluation function based on MTF(modulation transfer function), and the focus position is gotten at the only extreme point of the focusing curve. In the Matlab environment, the result shows that the focusing function based on the MTF of the digital image can only use 0.01 s to calculate the definition value of a single image. The algorithm has the better real-time performance, higher sensitivity and application value.
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Received: 30 January 2019
Published: 13 August 2020
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2020, Vol. 41 
