{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T15:59:49Z","timestamp":1778255989341,"version":"3.51.4"},"reference-count":44,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2021,4,29]],"date-time":"2021-04-29T00:00:00Z","timestamp":1619654400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100013704","name":"Consejo Nacional de Ciencia y Tecnolog\u00eda, Paraguay","doi-asserted-by":"publisher","award":["POSG17-53"],"award-info":[{"award-number":["POSG17-53"]}],"id":[{"id":"10.13039\/501100013704","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Panoramic dental radiography is one of the most used images of the different dental specialties. This radiography provides information about the anatomical structures of the teeth. The correct evaluation of these radiographs is associated with a good quality of the image obtained. In this study, 598 patients were consecutively selected to undergo dental panoramic radiography at the Department of Radiology of the Faculty of Dentistry, Universidad Nacional de Asunci\u00f3n. Contrast enhancement techniques are used to enhance the visual quality of panoramic dental radiographs. Specifically, this article presents a new algorithm for contrast, detail and edge enhancement of panoramic dental radiographs. The proposed algorithm is called Multi-Scale Top-Hat transform powered by Geodesic Reconstruction for panoramic dental radiography enhancement (MSTHGR). This algorithm is based on multi-scale mathematical morphology techniques. The proposal extracts multiple features of brightness and darkness, through the reconstruction of the marker (obtained by the Top-Hat transformation by reconstruction) starting from the mask (obtained by the classic Top-Hat transformation). The maximum characteristics of brightness and darkness are added to the dental panoramic radiography. In this way, the contrast, details and edges of the panoramic radiographs of teeth are improved. For the tests, MSTHGR was compared with the following algorithms: Geodesic Reconstruction Multiscale Morphology Contrast Enhancement (GRMMCE), Histogram Equalization (HE), Brightness Preserving Bi-Histogram Equalization (BBHE), Dual Sub-Image Histogram Equalization (DSIHE), Minimum Mean Brightness Error Bi-Histogram Equalization (MMBEBHE), Quadri-Histogram Equalization with Limited Contrast (QHELC), Contrast-Limited Adaptive Histogram Equalization (CLAHE) and Gamma Correction (GC). Experimentally, the numerical results show that the MSTHGR obtained the best results with respect to the Contrast Improvement Ratio (CIR), Entropy (E) and Spatial Frequency (SF) metrics. This indicates that the algorithm performs better local enhancements on panoramic radiographs, improving their details and edges.<\/jats:p>","DOI":"10.3390\/s21093110","type":"journal-article","created":{"date-parts":[[2021,4,29]],"date-time":"2021-04-29T10:30:41Z","timestamp":1619692241000},"page":"3110","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":57,"title":["Panoramic Dental Radiography Image Enhancement Using Multiscale Mathematical Morphology"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3698-4043","authenticated-orcid":false,"given":"Julio C\u00e9sar Mello","family":"Rom\u00e1n","sequence":"first","affiliation":[{"name":"Facultad Polit\u00e9cnica, Universidad Nacional de Asunci\u00f3n, San Lorenzo 111421, Paraguay"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3457-9017","authenticated-orcid":false,"given":"Vicente R.","family":"Fretes","sequence":"additional","affiliation":[{"name":"Facultad de Odontolog\u00eda, Universidad Nacional de Asunci\u00f3n, Asunci\u00f3n 001218, Paraguay"},{"name":"Departamento de Odontologia Restauradora, Faculdade de Odontologia de Ribeir\u00e3o Preto, Universidade de S\u00e3o Paulo, Ribeir\u00e3o Preto 14040-904, SP, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7118-2361","authenticated-orcid":false,"given":"Carlos G.","family":"Adorno","sequence":"additional","affiliation":[{"name":"Facultad de Odontolog\u00eda, Universidad Nacional de Asunci\u00f3n, Asunci\u00f3n 001218, Paraguay"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2568-7999","authenticated-orcid":false,"given":"Ricardo Gariba","family":"Silva","sequence":"additional","affiliation":[{"name":"Departamento de Odontologia Restauradora, Faculdade de Odontologia de Ribeir\u00e3o Preto, Universidade de S\u00e3o Paulo, Ribeir\u00e3o Preto 14040-904, SP, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9766-4182","authenticated-orcid":false,"given":"Jos\u00e9 Luis V\u00e1zquez","family":"Noguera","sequence":"additional","affiliation":[{"name":"Facultad Polit\u00e9cnica, Universidad Nacional de Asunci\u00f3n, San Lorenzo 111421, Paraguay"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1790-2559","authenticated-orcid":false,"given":"Horacio","family":"Legal-Ayala","sequence":"additional","affiliation":[{"name":"Facultad Polit\u00e9cnica, Universidad Nacional de Asunci\u00f3n, San Lorenzo 111421, Paraguay"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2821-7538","authenticated-orcid":false,"given":"Jorge Daniel","family":"Mello-Rom\u00e1n","sequence":"additional","affiliation":[{"name":"Facultad de Ciencias Exactas y Tecnol\u00f3gicas, Universidad Nacional de Conepci\u00f3n, Concepci\u00f3n 010123, Paraguay"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ricardo Daniel Escobar","family":"Torres","sequence":"additional","affiliation":[{"name":"Facultad de Ciencias Exactas y Tecnol\u00f3gicas, Universidad Nacional de Conepci\u00f3n, Concepci\u00f3n 010123, Paraguay"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5711-2826","authenticated-orcid":false,"given":"Jacques","family":"Facon","sequence":"additional","affiliation":[{"name":"Department of Computer and Electronics, Universidade Federal do Esp\u00edrito Santo, S\u00e3o Mateus 29932-540, ES, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,4,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"40","DOI":"10.1111\/j.1834-7819.2011.01655.x","article-title":"Interpretation of panoramic radiographs","volume":"57","author":"Perschbacher","year":"2012","journal-title":"Aust. 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