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The National Aeronautics and Space Administration (NASA) already deployed two Raman instruments, Super Cam and SHERLOC, onboard the Perseverance Rover in the Mars 2020 mission. In the ground test, the SHERLOC team found an axial offset (~720 \u03bcm) between the ACI (Autofocus Context Imager) and the spectrometer focus, which would obviously affect the acquired Raman intensity if not corrected. To eliminate this error and, more importantly, simplify the application of Raman instruments in deep space exploration missions, we propose an automatic focusing method wherein Raman signals are optimized during spectrum collection. We put forward a novel method that is realized by evaluating focus conditions numerically and searching for the extremum point as the final focal point. To verify the effectiveness of this method, we developed an Auto-focus Raman Probe (SDU-ARP) in our laboratory. This method provides a research direction for scenarios in which spectrometers cannot focus on a target using any other criterion. The utilization of this auto-focusing method can offer better spectra and fewer acquisitions in focusing procedure, and the spectrometer payload can be deployed in light-weight bodies (e.g., asteroids) or in poor illumination conditions (e.g., the permanently shadowed region in the Lunar south polar area) in deep space exploration missions.<\/jats:p>","DOI":"10.3390\/rs16050820","type":"journal-article","created":{"date-parts":[[2024,2,27]],"date-time":"2024-02-27T05:20:32Z","timestamp":1709011232000},"page":"820","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["A Signal-Based Auto-Focusing Method Available for Raman Spectroscopy Acquisitions in Deep Space Exploration"],"prefix":"10.3390","volume":"16","author":[{"given":"Yiheng","family":"Liu","sequence":"first","affiliation":[{"name":"Shandong Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and Physics, Institute of Space Sciences, Shandong University, Weihai 264209, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7864-3140","authenticated-orcid":false,"given":"Changqing","family":"Liu","sequence":"additional","affiliation":[{"name":"Shandong Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and Physics, Institute of Space Sciences, Shandong University, Weihai 264209, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3702-6792","authenticated-orcid":false,"given":"Yanqing","family":"Xin","sequence":"additional","affiliation":[{"name":"Shandong Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and Physics, Institute of Space Sciences, Shandong University, Weihai 264209, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3414-0285","authenticated-orcid":false,"given":"Ping","family":"Liu","sequence":"additional","affiliation":[{"name":"Shandong Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and Physics, Institute of Space Sciences, Shandong University, Weihai 264209, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ayang","family":"Xiao","sequence":"additional","affiliation":[{"name":"Shandong Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and Physics, Institute of Space Sciences, Shandong University, Weihai 264209, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9260-5765","authenticated-orcid":false,"given":"Zongcheng","family":"Ling","sequence":"additional","affiliation":[{"name":"Shandong Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and Physics, Institute of Space Sciences, Shandong University, Weihai 264209, China"},{"name":"CAS Center for Excellence in Comparative Planetology, Chinese Academy of Sciences, Hefei 230026, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,2,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"042004","DOI":"10.1088\/2515-7647\/ac1cd7","article-title":"Low Frequency Coherent Raman Spectroscopy","volume":"3","author":"Bartels","year":"2021","journal-title":"J. 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Anal."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"053101","DOI":"10.1063\/1.5088039","article-title":"Raman Spectrometer for the Automated Scan of Large Painted Surfaces","volume":"90","author":"Mencaglia","year":"2019","journal-title":"Rev. Sci. Instrum."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"137","DOI":"10.1366\/11-06535","article-title":"Remote Raman Spectroscopy for Planetary Exploration: A Review","volume":"66","author":"Angel","year":"2012","journal-title":"Appl. Spectrosc."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"281","DOI":"10.1007\/s11214-007-9279-y","article-title":"Raman Spectroscopy\u2014A Powerful Tool for in Situ Planetary Science","volume":"135","author":"Tarcea","year":"2008","journal-title":"Space Sci. Rev."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"627","DOI":"10.1089\/ast.2016.1567","article-title":"The Raman Laser Spectrometer for the ExoMars Rover Mission to Mars","volume":"17","author":"Rull","year":"2017","journal-title":"Astrobiology"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"4","DOI":"10.1007\/s11214-020-00777-5","article-title":"The SuperCam Instrument Suite on the NASA Mars 2020 Rover: Body Unit and Combined System Tests","volume":"217","author":"Wiens","year":"2021","journal-title":"Space Sci. Rev."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1089\/ast.2022.0023","article-title":"A Deep Ultraviolet Raman and Fluorescence Spectral Library of 51 Organic Compounds for the SHERLOC Instrument Onboard Mars 2020","volume":"23","author":"Sharma","year":"2023","journal-title":"Astrobiology"},{"key":"ref_17","unstructured":"Chi, W., Yingzhuo, J., Changbin, X., Yangting, L., Jianzhong, L., Xiaohui, F., Lin, X., Yun, H., Yufen, Z., and Yigang, X. (2023). Scientific Objectives and Payload Configuration of the Chang\u2019E-7 Mission. Natl. Sci. Rev., nwad329."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/s40623-021-01496-z","article-title":"In Situ Science on Phobos with the Raman Spectrometer for MMX (RAX): Preliminary Design and Feasibility of Raman Measurements","volume":"73","author":"Cho","year":"2021","journal-title":"Earth Planets Space"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"27354","DOI":"10.1364\/OE.27.027354","article-title":"Centroid-Position-Based Autofocusing Technique for Raman Spectroscopy","volume":"27","author":"Cui","year":"2019","journal-title":"Opt. Express"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"58","DOI":"10.1007\/s11214-021-00812-z","article-title":"Perseverance\u2019s Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) Investigation","volume":"217","author":"Bhartia","year":"2021","journal-title":"Space Sci. Rev."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"30760","DOI":"10.1364\/OE.401207","article-title":"Development and Evaluation of a Hand-Held Fiber-Optic Raman Probe with an Integrated Autofocus Unit","volume":"28","author":"Yang","year":"2020","journal-title":"Opt. Express"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Chen, G., Zhu, M., and Qiu, X. (2007, January 25\u201327). The Study of Image Definition Evaluation Function Based on Wavelet. Proceedings of the 2007 IEEE Symposium on Virtual Environments, Human-Computer Interfaces and Measurement Systems, Ostuni, Italy.","DOI":"10.1109\/VECIMS.2007.4373942"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Li, S., Chen, J., Wan, J., Li, Z., and Lin, L. (2021, January 20\u201322). Image Definition Evaluation Function Based on Improved Maximum Local Variation and Focusing Window Selection. Proceedings of the Data Mining and Big Data: 6th International Conference, DMBD 2021, Guangzhou, China.","DOI":"10.1007\/978-981-16-7502-7_9"},{"key":"ref_24","unstructured":"Mahdavi, K., Harman, M., and Hierons, R.M. (2003, January 22\u201326). A Multiple Hill Climbing Approach to Software Module Clustering. Proceedings of the International Conference on Software Maintenance, Proceedings, Amsterdam, The Netherlands."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1063\/1.168325","article-title":"Spline Algorithms for Continuum Functions","volume":"3","author":"Idrees","year":"1989","journal-title":"Comput. Phys."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"281","DOI":"10.1002\/ceat.200500375","article-title":"Factors Affecting the Polymorphic Outcome of Glycine Crystals Constrained on Patterned Substrates","volume":"29","author":"Lee","year":"2006","journal-title":"Chem. Eng. Technol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"997","DOI":"10.1016\/0022-1902(79)80076-7","article-title":"The Anomalous Behaviour of 18O-Labelled Compounds\u2014XVI[1]","volume":"41","author":"Pinchas","year":"1979","journal-title":"J. Inorg. Nucl. Chem."},{"key":"ref_28","first-page":"97","article-title":"The Raman Study of Certain Carbonates","volume":"2","author":"Buzgar","year":"2009","journal-title":"Geol. Tomul L"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1544","DOI":"10.1021\/mp300035g","article-title":"Investigating the Recrystallization Behavior of Amorphous Paracetamol by Variable Temperature Raman Studies and Surface Raman Mapping","volume":"9","author":"Nanubolu","year":"2012","journal-title":"Mol. Pharm."},{"key":"ref_30","first-page":"5","article-title":"The Composition and Source of the Raw Material of Two Stone Axes of Late Bronze Age from Neam\u021b County (Romania)\u2014A Raman Study","volume":"59","author":"Buzgar","year":"2013","journal-title":"Analele Stiintifice ale Universitatii \u201cAl. I. Cuza\u201d din Iasi Seria Geologie"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1849","DOI":"10.1016\/0584-8539(71)80238-6","article-title":"The Raman Spectrum of Gypsum","volume":"27","author":"Berenblut","year":"1971","journal-title":"Spectrochim. Acta Part A Mol. Spectrosc."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Zhao, X.Y., Liu, G.Y., Sui, Y.T., Xu, M., and Tong, L. (2021). Denoising Method for Raman Spectra with Low Signal-to-Noise Ratio Based on Feature Extraction. Spectrochim. Acta Part A Mol. Biomol. Spectrosc., 250.","DOI":"10.1016\/j.saa.2020.119374"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1016\/j.icarus.2010.08.020","article-title":"Mineralogy and Geochemistry of Four Lunar Soils by Laser-Raman Study","volume":"211","author":"Ling","year":"2011","journal-title":"Icarus"}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/16\/5\/820\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T14:05:37Z","timestamp":1760105137000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/16\/5\/820"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,2,27]]},"references-count":33,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2024,3]]}},"alternative-id":["rs16050820"],"URL":"https:\/\/doi.org\/10.3390\/rs16050820","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,2,27]]}}}