{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,6]],"date-time":"2026-06-06T15:07:47Z","timestamp":1780758467083,"version":"3.54.1"},"reference-count":41,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2022,10,7]],"date-time":"2022-10-07T00:00:00Z","timestamp":1665100800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>An algorithm for a sharpness evaluation of microscopic images based on non-subsampled shearlet wave transform (NSST) and variance is proposed in the present study for the purpose of improving the noise immunity and accuracy of a microscope\u2019s image autofocus. First, images are decomposed with the NSST algorithm; then, the decomposed sub-band images are subjected to variance to obtain the energy of the sub-band coefficients; and finally, the evaluation value is obtained from the ratio of the energy of the high- and low-frequency sub-band coefficients. The experimental results show that the proposed algorithm delivers better noise immunity performance than other methods reviewed by this study while maintaining high sensitivity.<\/jats:p>","DOI":"10.3390\/s22197607","type":"journal-article","created":{"date-parts":[[2022,10,10]],"date-time":"2022-10-10T05:12:21Z","timestamp":1665378741000},"page":"7607","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["A Method for Medical Microscopic Images\u2019 Sharpness Evaluation Based on NSST and Variance by Combining Time and Frequency Domains"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6682-3734","authenticated-orcid":false,"given":"Xuecheng","family":"Wu","sequence":"first","affiliation":[{"name":"School of Mathematics and Computer Science, Zhejiang A & F University, Hangzhou 311300, China"},{"name":"Zhejiang Provincial Key Laboratory of Forestry Intelligent Monitoring and Information Technology, Hangzhou 311300, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7915-8684","authenticated-orcid":false,"given":"Houkui","family":"Zhou","sequence":"additional","affiliation":[{"name":"School of Mathematics and Computer Science, Zhejiang A & F University, Hangzhou 311300, China"},{"name":"Zhejiang Provincial Key Laboratory of Forestry Intelligent Monitoring and Information Technology, Hangzhou 311300, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Huimin","family":"Yu","sequence":"additional","affiliation":[{"name":"College of Information Science & Electronic Engineering, Zhejiang University, Hangzhou 310027, China"},{"name":"State Key Laboratory of CAD & CG, Hangzhou 310027, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Roland","family":"Hu","sequence":"additional","affiliation":[{"name":"College of Information Science & Electronic Engineering, Zhejiang University, Hangzhou 310027, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Guangqun","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Mathematics and Computer Science, Zhejiang A & F University, Hangzhou 311300, China"},{"name":"Zhejiang Provincial Key Laboratory of Forestry Intelligent Monitoring and Information Technology, Hangzhou 311300, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Junguo","family":"Hu","sequence":"additional","affiliation":[{"name":"School of Mathematics and Computer Science, Zhejiang A & F University, Hangzhou 311300, China"},{"name":"Zhejiang Provincial Key Laboratory of Forestry Intelligent Monitoring and Information Technology, Hangzhou 311300, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5304-3010","authenticated-orcid":false,"given":"Tao","family":"He","sequence":"additional","affiliation":[{"name":"School of Mathematics and Computer Science, Zhejiang A & F University, Hangzhou 311300, China"},{"name":"Zhejiang Provincial Key Laboratory of Forestry Intelligent Monitoring and Information Technology, Hangzhou 311300, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,10,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1166\/jamr.2015.1229","article-title":"Digital Analysis of Microscopic Images in Medicine","volume":"10","year":"2015","journal-title":"J. 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