{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,12]],"date-time":"2026-03-12T07:08:06Z","timestamp":1773299286801,"version":"3.50.1"},"reference-count":32,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2021,3,24]],"date-time":"2021-03-24T00:00:00Z","timestamp":1616544000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["2019R1A2C1089813"],"award-info":[{"award-number":["2019R1A2C1089813"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"name":"the Korea Medical Device Development Fund grant","award":["9991007146"],"award-info":[{"award-number":["9991007146"]}]},{"name":"Korea Medical Device Development Fund grants","award":["202012E02"],"award-info":[{"award-number":["202012E02"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>High-frequency ultrasound (HFUS) imaging has emerged as an essential tool for pre-clinical studies and clinical applications such as ophthalmic and dermatologic imaging. HFUS imaging systems based on array transducers capable of dynamic receive focusing have considerably improved the image quality in terms of spatial resolution and signal-to-noise ratio (SNR) compared to those by the single-element transducer-based one. However, the array system still suffers from low spatial resolution and SNR in out-of-focus regions, resulting in a blurred image and a limited penetration depth. In this paper, we present synthetic aperture imaging with a virtual source (SA-VS) for an ophthalmic application using a high-frequency convex array transducer. The performances of the SA-VS were evaluated with phantom and ex vivo experiments in comparison with the conventional dynamic receive focusing method. Pre-beamformed radio-frequency (RF) data from phantoms and excised bovine eye were acquired using a custom-built 64-channel imaging system. In the phantom experiments, the SA-VS method showed improved lateral resolution (&gt;10%) and sidelobe level (&gt;4.4 dB) compared to those by the conventional method. The SNR was also improved, resulting in an increased penetration depth: 16 mm and 23 mm for the conventional and SA-VS methods, respectively. Ex vivo images with the SA-VS showed improved image quality at the entire depth and visualized structures that were obscured by noise in conventional imaging.<\/jats:p>","DOI":"10.3390\/s21072275","type":"journal-article","created":{"date-parts":[[2021,3,24]],"date-time":"2021-03-24T21:36:51Z","timestamp":1616621811000},"page":"2275","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["Synthetic Aperture Imaging Using High-Frequency Convex Array for Ophthalmic Ultrasound Applications"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4182-7130","authenticated-orcid":false,"given":"Hae Gyun","family":"Lim","sequence":"first","affiliation":[{"name":"Department of Biomedical Engineering, Pukyong National University, Busan 48513, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6353-5550","authenticated-orcid":false,"given":"Hyung Ham","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Convergence IT Engineering, Pohang University of Science and Technology, Pohang 37673, Korea"}]},{"given":"Changhan","family":"Yoon","sequence":"additional","affiliation":[{"name":"Department of Biomedical Engineering, Inje University, Gimhae 50834, Korea"},{"name":"Department of Nanoscience and Engineering, Inje University, Gimhae 50834, Korea"}]}],"member":"1968","published-online":{"date-parts":[[2021,3,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1016\/0301-5629(94)00083-2","article-title":"A 40\u2013100 MHz B-scan ultrasound backscatter microscope for skin imaging","volume":"21","author":"Turnbull","year":"1995","journal-title":"Ultrasound Med. 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