{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T09:18:12Z","timestamp":1785403092220,"version":"3.56.0"},"reference-count":27,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2026,6,19]],"date-time":"2026-06-19T00:00:00Z","timestamp":1781827200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Innovation Fund Project for University Teachers in Gansu Province","award":["2025B-215"],"award-info":[{"award-number":["2025B-215"]}]},{"name":"Key Research and Development Program of Gansu Province\u2013Industrial Project","award":["25YFGM002"],"award-info":[{"award-number":["25YFGM002"]}]},{"name":"Scientific Research Projects of Higher Education Institutions in Gansu Province","award":["2026QB-096"],"award-info":[{"award-number":["2026QB-096"]}]},{"name":"Qingyang City Major Science and Technology Project\u2013Industrial Field Project","award":["2025JY1005"],"award-info":[{"award-number":["2025JY1005"]}]},{"name":"Doctoral Fund Project of Longdong University","award":["XYBYZK2510"],"award-info":[{"award-number":["XYBYZK2510"]}]},{"award":["XYBYZK2510"],"award-info":[{"award-number":["XYBYZK2510"]}],"id":[{"id":"https:\/\/ror.org\/03wcn4h12","id-type":"ROR","asserted-by":"publisher"}]},{"name":"Longdong University Higher Education Teaching Research 2026 Key Project","award":["LYJYJX2026A45"],"award-info":[{"award-number":["LYJYJX2026A45"]}]},{"award":["LYJYJX2026A45"],"award-info":[{"award-number":["LYJYJX2026A45"]}],"id":[{"id":"https:\/\/ror.org\/03wcn4h12","id-type":"ROR","asserted-by":"publisher"}]},{"name":"Crossing Research Project of Longdong University","award":["HXZK2547"],"award-info":[{"award-number":["HXZK2547"]}]},{"name":"Crossing Research Project of Longdong University","award":["HXZK2640"],"award-info":[{"award-number":["HXZK2640"]}]},{"award":["HXZK2547"],"award-info":[{"award-number":["HXZK2547"]}],"id":[{"id":"https:\/\/ror.org\/03wcn4h12","id-type":"ROR","asserted-by":"publisher"}]},{"award":["HXZK2640"],"award-info":[{"award-number":["HXZK2640"]}],"id":[{"id":"https:\/\/ror.org\/03wcn4h12","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Optical coherence tomography (OCT) is an optical imaging modality that provides high-resolution cross-sectional imaging of biological tissues noninvasively. In Fourier-domain OCT, axial resolution is governed by both the center wavelength and the spectral bandwidth of the light source; therefore, limited or discontinuous bandwidth degrades depth resolution and introduces sidelobes and artifacts in OCT images. To address these issues in OCT image reconstruction from gapped spectra, a sparse parameter estimation approach based on Sparse Iterative Covariance-based Estimation (SPICE) is proposed in this study. By utilizing a sparse parameter estimation framework to directly resolve depth-dependent components from discontinuous interferograms, SPICE enhances axial resolution while suppressing sidelobe artifacts inherent in standard interpolation. Experiments on multi-layered tape, oral epithelium, and finger skin show that SPICE visually suppresses gap-induced sidelobe artifacts and improves structural interpretability under representative gap conditions. Quantitative evaluations on multi-layer tape and biological tissues show that SPICE reduces axial FWHM by 30\u201345%, increases SSIM by 0.15\u20130.25, and achieves significantly lower computational cost than GAPES (p &lt; 0.01).<\/jats:p>","DOI":"10.3390\/s26123906","type":"journal-article","created":{"date-parts":[[2026,6,19]],"date-time":"2026-06-19T13:04:04Z","timestamp":1781874244000},"page":"3906","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Optical Coherence Tomography with Gapped Spectrum Using Sparse Iterative Covariance-Based Estimation"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0009-0000-9044-5772","authenticated-orcid":false,"given":"Xiaonan","family":"Pan","sequence":"first","affiliation":[{"name":"School of Intelligent Manufacturing, Longdong University, Qingyang 745000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-1674-3108","authenticated-orcid":false,"given":"Miao","family":"Yuan","sequence":"additional","affiliation":[{"name":"School of Automation, Northwestern Polytechnical University, Xi\u2019an 710072, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3042-0527","authenticated-orcid":false,"given":"Jianrui","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Intelligent Manufacturing, Longdong University, Qingyang 745000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7361-0780","authenticated-orcid":false,"given":"Xiaojun","family":"Yu","sequence":"additional","affiliation":[{"name":"School of Automation, Northwestern Polytechnical University, Xi\u2019an 710072, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1178","DOI":"10.1126\/science.1957169","article-title":"Optical coherence tomography","volume":"254","author":"Huang","year":"1991","journal-title":"Science"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1038\/s43586-022-00162-2","article-title":"Optical coherence tomography","volume":"2","author":"Bouma","year":"2022","journal-title":"Nat. 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