{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T01:03:15Z","timestamp":1760230995487,"version":"build-2065373602"},"reference-count":25,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2022,8,19]],"date-time":"2022-08-19T00:00:00Z","timestamp":1660867200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004663","name":"Ministry of Science and Technology","doi-asserted-by":"publisher","award":["MOST 111-2221-E-002-162","00023116","LF-OC-20-000370"],"award-info":[{"award-number":["MOST 111-2221-E-002-162","00023116","LF-OC-20-000370"]}],"id":[{"id":"10.13039\/501100004663","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Villum Experiment","award":["MOST 111-2221-E-002-162","00023116","LF-OC-20-000370"],"award-info":[{"award-number":["MOST 111-2221-E-002-162","00023116","LF-OC-20-000370"]}]},{"DOI":"10.13039\/501100012331","name":"LEO Foundation","doi-asserted-by":"publisher","award":["MOST 111-2221-E-002-162","00023116","LF-OC-20-000370"],"award-info":[{"award-number":["MOST 111-2221-E-002-162","00023116","LF-OC-20-000370"]}],"id":[{"id":"10.13039\/501100012331","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>An astigmatic optical profilometer with a commercial optical pickup head provides benefits, such as high resolution, compact size, and low cost. To eliminate artifacts caused by complex materials with different reflectances, a z-axis modulation mode is proposed to obtain quantitative surface morphology by measuring S curves on all image pixels. Moreover, the slope of the linear region in the S curve shows a positive relationship with the surface reflectance. However, the slope was calculated using an offline curve fitting method, which did not allow real-time reflectance imaging. Furthermore, quantitative reflectance data were unavailable because of the lack of calibration. In this study, we propose a novel method for real-time reflectance imaging by measuring the amplitude of a focus error signal (FES). The calibration results displayed a linear relationship between the FES amplitude and reflectance. The reflectance image of a grating sample with chrome patterns on a glass substrate demonstrates accurate reflectance measurements with a micrometer spatial resolution.<\/jats:p>","DOI":"10.3390\/s22166242","type":"journal-article","created":{"date-parts":[[2022,8,22]],"date-time":"2022-08-22T01:56:40Z","timestamp":1661133400000},"page":"6242","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Real-Time Reflectance Measurement Using an Astigmatic Optical Profilometer"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1338-0332","authenticated-orcid":false,"given":"Hsien-Shun","family":"Liao","sequence":"first","affiliation":[{"name":"Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ya-Kang","family":"Huang","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jian-Yuan","family":"Syu-Gu","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5971-4978","authenticated-orcid":false,"given":"En-Te","family":"Hwu","sequence":"additional","affiliation":[{"name":"Department of Health Technology, Technical University of Denmark, 2800 Lyngby, Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,8,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1016\/0001-8686(94)80026-X","article-title":"Reflectometry as a tool for adsorption studies","volume":"50","author":"Dijt","year":"1994","journal-title":"Adv. Colloid Interface Sci."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Wedowski, M., Underwood, J.H., Gullikson, E.M., Bajt, S., James, A., Folta, J.A., Kearney, P.A., Montcalm, C., and Spiller, E. (2000, January 21). High-Precision Reflectometry of Multilayer Coatings for Extreme Ultraviolet Lithography. Proceedings of the SPIE, Santa Clara, CA, USA.","DOI":"10.1117\/12.390107"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"055117","DOI":"10.1063\/1.5021704","article-title":"Simultaneous reflectometry and interferometry for measuring thin-film thickness and curvature","volume":"89","author":"Arends","year":"2018","journal-title":"Rev. Sci. Instrum."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"337","DOI":"10.1177\/0967033518806637","article-title":"Medical applications of reflectance spectroscopy in the diffusive and sub-diffusive regimes","volume":"26","author":"Akter","year":"2018","journal-title":"J. Near Infrared Spectrosc."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"547","DOI":"10.1023\/B:IJOT.0000028489.81327.b7","article-title":"Emissivity Measurements on Metallic Surfaces with Various Degrees of Roughness: A Comparison of Laser Polarimetry and Integrating Sphere Reflectometry","volume":"25","author":"Seifter","year":"2004","journal-title":"Int. J. Thermophys."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"043606","DOI":"10.1117\/1.3567057","article-title":"Diffractive optical element\u2013based glossmeter for the on-line measurement of normal reflectance on a printed porous coated paper","volume":"50","author":"Oksman","year":"2011","journal-title":"Opt. Eng."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"S97","DOI":"10.1088\/0026-1394\/40\/1\/322","article-title":"Gonioreflectometer-based gloss standard calibration","volume":"40","author":"Andor","year":"2003","journal-title":"Metrologia"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Gene, J., Jeon, M.Y., and Lim, S.D. (2021). Reflectometers for Absolute and Relative Reflectance Measurements in the Mid-IR Region at Vacuum. Sensors, 21.","DOI":"10.3390\/s21041169"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"025309","DOI":"10.1088\/0957-0233\/20\/2\/025309","article-title":"A reflectometer for the combined measurement of refractive index, microroughness, macroroughness and gloss of low-extinction surfaces","volume":"20","author":"Elton","year":"2009","journal-title":"Meas. Sci. Technol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"236","DOI":"10.1186\/1556-276X-6-236","article-title":"Anti-reflective nano- and micro-structures on 4H-SiC for photodiodes","volume":"6","author":"Kang","year":"2011","journal-title":"Nanoscale Res. Lett."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"7863","DOI":"10.1038\/s41598-018-26234-6","article-title":"Anti-reflectance investigation of a micro-nano hybrid structure fabricated by dry\/wet etching methods","volume":"8","author":"Tan","year":"2018","journal-title":"Sci. Rep."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"28","DOI":"10.1016\/j.solmat.2017.03.036","article-title":"Equipment and methods for measuring reflectance of concentrating solar reflector materials","volume":"167","author":"Sutter","year":"2017","journal-title":"Sol. Energy Mater. Sol. Cells"},{"key":"ref_13","unstructured":"Baron, E.L., Grosjean, A., Bourdon, D., Pescheux, A.-C., Vidal, F., and Disdier, A. (2020, January 11). New equipment for measurement of soiling and specular reflectance on solar mirrors. Proceedings of the AIP Conference Proceedings, Daegu, Korea."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1259","DOI":"10.1088\/0957-0233\/9\/8\/019","article-title":"A 3D optical profilometer using a compact disc reading head","volume":"9","author":"Ehrmann","year":"1998","journal-title":"Meas. Sci. Technol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"115501","DOI":"10.1088\/0957-4484\/19\/11\/115501","article-title":"Real-time detection of linear and angular displacements with a modified DVD optical head","volume":"19","author":"Hwu","year":"2008","journal-title":"Nanotechnology"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"084005","DOI":"10.1088\/0957-0233\/20\/8\/084005","article-title":"A hybrid scanning probe microscope (SPM) module based on a DVD optical head","volume":"20","author":"Hwu","year":"2009","journal-title":"Meas. Sci. Technol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1222","DOI":"10.1021\/acssensors.8b00340","article-title":"Hacking CD\/DVD\/Blu-ray for Biosensing","volume":"3","author":"Hwu","year":"2018","journal-title":"ACS Sens."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"2411","DOI":"10.1039\/c1lc20116f","article-title":"High throughput label-free platform for statistical bio-molecular sensing","volume":"11","author":"Bosco","year":"2011","journal-title":"Lab Chip"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1364\/BOE.4.000187","article-title":"Optical detection of nanoparticle-enhanced human papillomavirus genotyping microarrays","volume":"4","author":"Li","year":"2013","journal-title":"Biomed.Opt. Express"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"885","DOI":"10.2116\/analsci.29.885","article-title":"Biophysical analysis of astrocytes apoptosis triggered by larval E\/S antigen from cerebral toxocarosis-causing pathogen Toxocara canis","volume":"29","author":"Hsiao","year":"2013","journal-title":"Anal. Sci."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Liao, H.S., Cheng, S.H., and Hwu, E.T. (2022). Method for Film Thickness Mapping with an Astigmatic Optical Profilometer. Sensors, 22.","DOI":"10.3390\/s22082865"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"107002","DOI":"10.1088\/1361-6501\/aadc49","article-title":"A novel method for quantitative height measurement based on an astigmatic optical profilometer","volume":"29","author":"Liao","year":"2018","journal-title":"Meas. Sci. Technol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1172","DOI":"10.1109\/TMECH.2020.3011465","article-title":"Development of a Resonant Scanner to Improve the Imaging Rate of Astigmatic Optical Profilometers","volume":"26","author":"Liao","year":"2021","journal-title":"IEEE\/ASME T. Mech."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"103709","DOI":"10.1063\/1.4826494","article-title":"Operation of astigmatic-detection atomic force microscopy in liquid environments","volume":"84","author":"Liao","year":"2013","journal-title":"Rev. Sci. Instrum."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"053706","DOI":"10.1063\/1.4952438","article-title":"Optical imaging module for astigmatic detection system","volume":"87","author":"Wang","year":"2016","journal-title":"Rev. Sci. Instrum."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/16\/6242\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T00:12:30Z","timestamp":1760141550000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/16\/6242"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,8,19]]},"references-count":25,"journal-issue":{"issue":"16","published-online":{"date-parts":[[2022,8]]}},"alternative-id":["s22166242"],"URL":"https:\/\/doi.org\/10.3390\/s22166242","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2022,8,19]]}}}