{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,22]],"date-time":"2026-03-22T06:52:08Z","timestamp":1774162328513,"version":"3.50.1"},"reference-count":34,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2023,12,29]],"date-time":"2023-12-29T00:00:00Z","timestamp":1703808000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","award":["2022YFB3902400"],"award-info":[{"award-number":["2022YFB3902400"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","award":["2022JJ10063"],"award-info":[{"award-number":["2022JJ10063"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","award":["61921001"],"award-info":[{"award-number":["61921001"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","award":["62171446"],"award-info":[{"award-number":["62171446"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","award":["62322122"],"award-info":[{"award-number":["62322122"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Distinguished Youth Science Foundation of Hunan Province","award":["2022YFB3902400"],"award-info":[{"award-number":["2022YFB3902400"]}]},{"name":"Distinguished Youth Science Foundation of Hunan Province","award":["2022JJ10063"],"award-info":[{"award-number":["2022JJ10063"]}]},{"name":"Distinguished Youth Science Foundation of Hunan Province","award":["61921001"],"award-info":[{"award-number":["61921001"]}]},{"name":"Distinguished Youth Science Foundation of Hunan Province","award":["62171446"],"award-info":[{"award-number":["62171446"]}]},{"name":"Distinguished Youth Science Foundation of Hunan Province","award":["62322122"],"award-info":[{"award-number":["62322122"]}]},{"name":"National Natural Science Foundation of China","award":["2022YFB3902400"],"award-info":[{"award-number":["2022YFB3902400"]}]},{"name":"National Natural Science Foundation of China","award":["2022JJ10063"],"award-info":[{"award-number":["2022JJ10063"]}]},{"name":"National Natural Science Foundation of China","award":["61921001"],"award-info":[{"award-number":["61921001"]}]},{"name":"National Natural Science Foundation of China","award":["62171446"],"award-info":[{"award-number":["62171446"]}]},{"name":"National Natural Science Foundation of China","award":["62322122"],"award-info":[{"award-number":["62322122"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The extraction of the micro-Doppler (m-D) feature based on time-frequency distribution (TFD) is of great significance for target detection and identification. To improve the feature extraction performance, numerous TFDs have been developed, with the majority falling under Cohen\u2019s class. Nevertheless, these TFDs basically face a trade-off between artifact suppression and energy concentration. The main reason is that each Cohen\u2019s class TFD is constructed by applying the two-dimensional Fourier transform to a kerneled ambiguity function directly, while existing kernels generally attenuate artifacts at the expense of losing valuable information. In this paper, a TFD reconstruction method employing an adaptive short-time kernel (ASTK) is developed in the framework of sparse representation (SR) theory to overcome this trade-off and enhance the m-D feature. Firstly, the task of the optimal kernel is explained from the viewpoint of the instantaneous auto-correlation function (IAF). Secondly, based on the quasi-linear frequency modulation feature of most m-D signals during short-time periods, the distribution rule of the short-time IAF (STIAF) in the ambiguity plane is concluded. Guided by this rule, an ASTK that can effectively remove unwanted artifacts with the least information loss is designed. Finally, an SR-based reconstruction procedure is conducted on the kerneled STIAF to generate an artifact-free TFD with high energy concentration, which can effectively enhance the m-D feature. Experiments using both simulated and real-world m-D signals demonstrate the effectiveness of the proposed method.<\/jats:p>","DOI":"10.3390\/rs16010146","type":"journal-article","created":{"date-parts":[[2023,12,29]],"date-time":"2023-12-29T06:18:13Z","timestamp":1703830693000},"page":"146","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Enhanced Micro-Doppler Feature Extraction Using Adaptive Short-Time Kernel-Based Sparse Time-Frequency Distribution"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0556-4847","authenticated-orcid":false,"given":"Yang","family":"Yang","sequence":"first","affiliation":[{"name":"College of Electronic Science and Technology, National University of Defense Technology, Changsha 410073, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0127-384X","authenticated-orcid":false,"given":"Yongqiang","family":"Cheng","sequence":"additional","affiliation":[{"name":"College of Electronic Science and Technology, National University of Defense Technology, Changsha 410073, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8679-1274","authenticated-orcid":false,"given":"Hao","family":"Wu","sequence":"additional","affiliation":[{"name":"College of Electronic Science and Technology, National University of Defense Technology, Changsha 410073, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6087-6571","authenticated-orcid":false,"given":"Zheng","family":"Yang","sequence":"additional","affiliation":[{"name":"College of Electronic Science and Technology, National University of Defense Technology, Changsha 410073, China"}]},{"given":"Hongqiang","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Electronic Science and Technology, National University of Defense Technology, Changsha 410073, China"}]}],"member":"1968","published-online":{"date-parts":[[2023,12,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1109\/TAES.2006.1603402","article-title":"Micro-Doppler effect in radar: Phenomenon, model, and simulation study","volume":"42","author":"Chen","year":"2006","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1002","DOI":"10.1109\/TGRS.2013.2246574","article-title":"Detection and extraction of target with micromotion in spiky sea clutter via short-time fractional Fourier transform","volume":"52","author":"Chen","year":"2013","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"12165","DOI":"10.1109\/JSEN.2019.2937173","article-title":"Sparse fractional energy distribution and its application to radar detection of marine targets with micro-motion","volume":"19","author":"Zhao","year":"2019","journal-title":"IEEE Sens. J."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"914","DOI":"10.1049\/iet-rsn.2012.0327","article-title":"Micro-Doppler feature extraction for wideband imaging radar based on complex image orthogonal matching pursuit decomposition","volume":"7","author":"Luo","year":"2013","journal-title":"IET Radar Sonar Navig."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"4937","DOI":"10.1109\/JSTARS.2014.2318596","article-title":"Micro-Doppler parameter estimation via parametric sparse representation and pruned orthogonal matching pursuit","volume":"7","author":"Li","year":"2014","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"755","DOI":"10.1109\/TAP.2013.2291893","article-title":"Radar signature analysis using a joint time-frequency distribution based on compressed sensing","volume":"62","author":"Whitelonis","year":"2013","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"950","DOI":"10.1049\/iet-rsn.2012.0322","article-title":"Modulation effect and inverse synthetic aperture radar imaging of rotationally symmetric ballistic targets with precession","volume":"7","author":"Pan","year":"2013","journal-title":"IET Radar Sonar Navig."},{"key":"ref_8","first-page":"92","article-title":"Micro-Doppler analysis of multiple frequency continuous wave radar signatures","volume":"Volume 6547","author":"Anderson","year":"2007","journal-title":"Proceedings of the Radar Sensor Technology XI"},{"key":"ref_9","unstructured":"Marple, S. (2003, January 3\u20135). Sharpening and bandwidth extrapolation techniques for radar micro-Doppler feature extraction. Proceedings of the 2003 International Conference on Radar, Adelaide, Australia."},{"key":"ref_10","first-page":"260","article-title":"Large dynamic range time-frequency signal analysis with application to helicopter Doppler radar data","volume":"Volume 1","author":"Marple","year":"2001","journal-title":"Proceedings of the Sixth International Symposium on Signal Processing and Its Applications"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1309","DOI":"10.1049\/el:20071515","article-title":"Analysis of microDopplers from human gait using reassigned joint time-frequency transform","volume":"43","author":"Ram","year":"2007","journal-title":"Electron. Lett."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"679","DOI":"10.1016\/j.jfranklin.2008.04.001","article-title":"Doppler-based detection and tracking of humans in indoor environments","volume":"345","author":"Ram","year":"2008","journal-title":"J. Frankl. Inst."},{"key":"ref_13","unstructured":"Boashash, B. (2015). Time-Frequency Signal Analysis and Processing: A Comprehensive Reference, Academic Press."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"288","DOI":"10.1016\/j.sigpro.2015.07.026","article-title":"Cross-terms reduction in the Wigner\u2013Ville distribution using tunable-Q wavelet transform","volume":"120","author":"Pachori","year":"2016","journal-title":"Signal Process."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"2836","DOI":"10.1109\/78.324750","article-title":"Decomposition of the Wigner-Ville distribution and time-frequency distribution series","volume":"42","author":"Qian","year":"1994","journal-title":"IEEE Trans. Signal Process."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"386","DOI":"10.1016\/j.jappgeo.2009.03.004","article-title":"Spectral decomposition of seismic data with reassigned smoothed pseudo Wigner\u2013Ville distribution","volume":"68","author":"Wu","year":"2009","journal-title":"J. Appl. Geophys."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"781","DOI":"10.1063\/1.1931206","article-title":"Generalized phase-space distribution functions","volume":"7","author":"Cohen","year":"1966","journal-title":"J. Math. Phys."},{"key":"ref_18","unstructured":"Flandrin, P. (1984, January 19\u201321). Some features of time-frequency representations of multicomponent signals. Proceedings of the ICASSP \u201984: IEEE International Conference on Acoustics, Speech, and Signal Processing, San Diego, CA, USA."},{"key":"ref_19","unstructured":"Cohen, L., and Posch, T.E. (1985, January 26\u201329). Generalized ambiguity functions. Proceedings of the IEEE International Conference on Acoustics, Speech, Signal Processing, Tampa, FL, USA."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"862","DOI":"10.1109\/ASSP.1989.28057","article-title":"Improved time-frequency representation of multicomponent signals using exponential kernels","volume":"37","author":"Choi","year":"1989","journal-title":"IEEE Trans. Acoust. Speech Signal Process."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"263","DOI":"10.1016\/0165-1684(93)90001-Q","article-title":"Signal-dependent time-frequency analysis using a radially Gaussian kernel","volume":"32","author":"Baraniuk","year":"1993","journal-title":"Signal Process."},{"key":"ref_22","unstructured":"Cohen, L. (1995). Time-Frequency Analysis, Prentice Hall."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1589","DOI":"10.1109\/78.212733","article-title":"A signal-dependent time-frequency representation: Optimal kernel design","volume":"41","author":"Baraniuk","year":"1993","journal-title":"IEEE Trans. Signal Process."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"2361","DOI":"10.1109\/78.469854","article-title":"An adaptive optimal-kernel time-frequency representation","volume":"43","author":"Jones","year":"1993","journal-title":"IEEE Trans. Signal Process."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"6698","DOI":"10.1109\/TSP.2015.2477056","article-title":"Reduced interference sparse time-frequency distributions for compressed observations","volume":"63","author":"Jokanovic","year":"2015","journal-title":"IEEE Trans. Signal Process."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1016\/j.dsp.2015.06.011","article-title":"A sparsity-perspective to quadratic time\u2013frequency distributions","volume":"46","author":"Amin","year":"2015","journal-title":"Digit. Signal Process."},{"key":"ref_27","first-page":"1","article-title":"Time\u2013Frequency Feature Enhancement of Moving Target Based on Adaptive Short-Time Sparse Representation","volume":"19","author":"Yang","year":"2022","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"3963","DOI":"10.1109\/TSP.2021.3089291","article-title":"Design of an optimal piece-wise spline Wigner-Ville distribution for TFD performance evaluation and comparison","volume":"69","author":"Boashash","year":"2021","journal-title":"IEEE Trans. Signal Process."},{"key":"ref_29","first-page":"127","article-title":"Time-frequency signature sparse reconstruction using chirp dictionary","volume":"Volume 9484","author":"Nguyen","year":"2015","journal-title":"Proceedings of the Compressive Sensing IV"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"136","DOI":"10.1109\/TSP.2020.3039871","article-title":"Ridge-Aware Weighted Sparse Time-Frequency Representation","volume":"69","author":"Tong","year":"2021","journal-title":"IEEE Trans. Signal Process."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"2974","DOI":"10.1109\/TSP.2010.2044839","article-title":"Time-Frequency Energy Distributions Meet Compressed Sensing","volume":"58","author":"Flandrin","year":"2010","journal-title":"IEEE Trans. Signal Process."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"479","DOI":"10.1109\/TAES.2014.140080","article-title":"Cross-term-free time\u2013frequency distribution reconstruction via lifted projections","volume":"51","author":"Deprem","year":"2015","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"289","DOI":"10.1109\/TSP.2008.2007606","article-title":"A Fast Approach for Overcomplete Sparse Decomposition Based on Smoothed \u21130 Norm","volume":"57","author":"Mohimani","year":"2009","journal-title":"IEEE Trans. Signal Process."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"3949","DOI":"10.1007\/s00034-014-9832-3","article-title":"High resolution time-frequency distribution based on short-time sparse representation","volume":"33","author":"Liu","year":"2014","journal-title":"Circuits Syst. Signal Process."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/16\/1\/146\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T21:44:04Z","timestamp":1760132644000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/16\/1\/146"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,12,29]]},"references-count":34,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2024,1]]}},"alternative-id":["rs16010146"],"URL":"https:\/\/doi.org\/10.3390\/rs16010146","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,12,29]]}}}