{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:40:38Z","timestamp":1760244038161,"version":"build-2065373602"},"reference-count":10,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2009,12,24]],"date-time":"2009-12-24T00:00:00Z","timestamp":1261612800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A focusing procedure in the calibration process of image sensors based on Incoherent Optical Fiber Bundles (IOFBs) is described using the information extracted from fibers. These procedures differ from any other currently known focusing method due to the non spatial in-out correspondence between fibers, which produces a natural codification of the image to transmit. Focus measuring is essential prior to carrying out calibration in order to guarantee accurate processing and decoding. Four algorithms have been developed to estimate the focus measure; two methods based on mean grey level, and the other two based on variance. In this paper, a few simple focus measures are defined and compared. Some experimental results referred to the focus measure and the accuracy of the developed methods are discussed in order to demonstrate its effectiveness.<\/jats:p>","DOI":"10.3390\/s100100047","type":"journal-article","created":{"date-parts":[[2009,12,25]],"date-time":"2009-12-25T09:26:52Z","timestamp":1261733212000},"page":"47-60","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["A Focusing Method in the Calibration Process of Image Sensors Based on IOFBs"],"prefix":"10.3390","volume":"10","author":[{"given":"Pedro R.","family":"Fern\u00e1ndez","sequence":"first","affiliation":[{"name":"Electronics Department, Superior Polytechnic School, University of Alcal\u00e1, Universitary Campus, Alcal\u00e1 de Henares 28871, Madrid, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5048-7134","authenticated-orcid":false,"given":"Jos\u00e9 L.","family":"L\u00e1zaro","sequence":"additional","affiliation":[{"name":"Electronics Department, Superior Polytechnic School, University of Alcal\u00e1, Universitary Campus, Alcal\u00e1 de Henares 28871, Madrid, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7887-4689","authenticated-orcid":false,"given":"Alfredo","family":"Gardel","sequence":"additional","affiliation":[{"name":"Electronics Department, Superior Polytechnic School, University of Alcal\u00e1, Universitary Campus, Alcal\u00e1 de Henares 28871, Madrid, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"\u00c1ngel E.","family":"Cano","sequence":"additional","affiliation":[{"name":"Telecommunication Department, University of Oriente, Av. de las Am\u00e9ricas, SN, Santiago de Cuba 90900, Cuba"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6964-0036","authenticated-orcid":false,"given":"Ignacio","family":"Bravo","sequence":"additional","affiliation":[{"name":"Electronics Department, Superior Polytechnic School, University of Alcal\u00e1, Universitary Campus, Alcal\u00e1 de Henares 28871, Madrid, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2009,12,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2996","DOI":"10.1109\/TIM.2009.2016807","article-title":"Location of Optical Fibers for the Calibration of Incoherent Optical Fiber Bundles for Image Transmission","volume":"58","author":"Fernandez","year":"2009","journal-title":"IEEE Instrum. Meas. Trans"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"8215","DOI":"10.3390\/s91008215","article-title":"Calibration of Sensor Based on IOFB Used For Remote Image Transmission","volume":"9","author":"Gardel","year":"2009","journal-title":"Sensors"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"128","DOI":"10.1049\/ip-vis:20040395","article-title":"Image Focus Measure Based on Chebyshev Moments","volume":"151","author":"Yap","year":"2004","journal-title":"IEE Proc.\u2014Vis. Image Signal Pro"},{"key":"ref_4","unstructured":"Wu, S., Lin, W., Jiang, L., and Xiong, W. (,  2005). An Objective Out-of-Focus Blur Measurement. Bangkok, Thailand."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"864","DOI":"10.1109\/34.709612","article-title":"Selecting the Optimal Focus Measure for Autofocusing and Depth-from-Focus","volume":"20","author":"Subbarao","year":"1998","journal-title":"IEEE Trans. Patt. Anal. Mach. Int"},{"key":"ref_6","unstructured":"Shen, C., and Chen, H. (,  2006). Robust focus Measure for Low-Contrast Images. Las Vegas, NM, USA."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Sezan, M.I., Pavlovic, G., Murat, A., and Tanju, A. (,  1991). On Modelling the Focus Blur in Image Restoration. Toronto, Ont., Canada.","DOI":"10.1109\/ICASSP.1991.150905"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Subbarao, M., and Tyan, J. (,  1995). The optimal Focus Measure for Passive Autofocusing and Depth-from-Focus. Philadelphia, PA, USA.","DOI":"10.1117\/12.220891"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2824","DOI":"10.1117\/12.147706","article-title":"Focusing Techniques","volume":"32","author":"Subbarao","year":"1993","journal-title":"J. Opt. Eng"},{"key":"ref_10","unstructured":"Tsai, T., and Lin, C. (,  2008). A New Auto-Focus Method Based on Focal Window Searching and Tracking Approach for Digital Camera. St. Julians, Malta."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/10\/1\/47\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T22:12:06Z","timestamp":1760220726000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/10\/1\/47"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2009,12,24]]},"references-count":10,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2010,1]]}},"alternative-id":["s100100047"],"URL":"https:\/\/doi.org\/10.3390\/s100100047","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2009,12,24]]}}}