{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,14]],"date-time":"2025-10-14T07:14:58Z","timestamp":1760426098643,"version":"build-2065373602"},"reference-count":29,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2022,12,31]],"date-time":"2022-12-31T00:00:00Z","timestamp":1672444800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Key Research and Development Project of China","award":["2021YFD1500103","4197132","20210201044GX","XDA28100500","CASPLOS-CCSI"],"award-info":[{"award-number":["2021YFD1500103","4197132","20210201044GX","XDA28100500","CASPLOS-CCSI"]}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["2021YFD1500103","4197132","20210201044GX","XDA28100500","CASPLOS-CCSI"],"award-info":[{"award-number":["2021YFD1500103","4197132","20210201044GX","XDA28100500","CASPLOS-CCSI"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Science and Technology Development Plan Project of Jilin province","award":["2021YFD1500103","4197132","20210201044GX","XDA28100500","CASPLOS-CCSI"],"award-info":[{"award-number":["2021YFD1500103","4197132","20210201044GX","XDA28100500","CASPLOS-CCSI"]}]},{"name":"Strategic Priority Research Program of the Chinese Academy of Sciences, China","award":["2021YFD1500103","4197132","20210201044GX","XDA28100500","CASPLOS-CCSI"],"award-info":[{"award-number":["2021YFD1500103","4197132","20210201044GX","XDA28100500","CASPLOS-CCSI"]}]},{"name":"Land Observation Satellite Supporting Platform of National Civil Space Infrastructure Project","award":["2021YFD1500103","4197132","20210201044GX","XDA28100500","CASPLOS-CCSI"],"award-info":[{"award-number":["2021YFD1500103","4197132","20210201044GX","XDA28100500","CASPLOS-CCSI"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>In order to reduce the impact of noise on the accuracy of inversion products based on SAR images, many filtering algorithms have been developed for noise reduction of SAR images. This paper proposes a filtering method based on the spatial autocorrelation feature of the block fast Fourier transform (BFFT). The method statistically analyses the autocorrelation length of speckle noise on Sentinel-1B images for different features and then constructs a relationship between autocorrelation length and noise period. After that, the size of the optimal FFT filtering window radius was determined based on the relationship between the noise period and the components in the image frequency domain. Finally, we filtered the SAR image within the parcels. We compared BFFT with six commonly used filtering methods. The results show that: (1) The noise periods of the soybean, corn, paddy, and water objects on the SAR image have little difference, with noise periods of 3.36, 3.17, 3.13, and 3.14 pixels on the VV polarization and 3.49, 3.17, 2.94, and 2.42 pixels on the VH polarization; (2) after the BFFT filtering in the land parcel area, the mean value of the backscattering coefficient (BC) kept constant, whilst at the same time, the standard deviation (STD) was reduced to half of that before the filtering and (3) the BFFT and NLM filtering methods have a better effect on noise reduction inside the block. The BFFT filtering method retains the variation trend between different regions within the block and preserves the block boundary\u2019s clarity. This study provides a new idea for refined image processing.<\/jats:p>","DOI":"10.3390\/rs15010247","type":"journal-article","created":{"date-parts":[[2023,1,2]],"date-time":"2023-01-02T03:00:59Z","timestamp":1672628459000},"page":"247","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["A Block-Scale FFT Filter Based on Spatial Autocorrelation Features of Speckle Noise in SAR Image"],"prefix":"10.3390","volume":"15","author":[{"given":"Xigang","family":"Wang","sequence":"first","affiliation":[{"name":"College of Geoexploration Science and Technology, Jilin University, Changchun 130026, China"},{"name":"Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China"},{"name":"Changchun Jingyuetan Remote Sensing Test Site, Changchun 130102, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4598-087X","authenticated-orcid":false,"given":"Zhiguo","family":"Meng","sequence":"additional","affiliation":[{"name":"College of Geoexploration Science and Technology, Jilin University, Changchun 130026, China"}]},{"given":"Si","family":"Chen","sequence":"additional","affiliation":[{"name":"School of Geomatics and Prospecting Engineering, Jilin Jianzhu University, Changchun 130118, China"}]},{"given":"Zhuangzhuang","family":"Feng","sequence":"additional","affiliation":[{"name":"Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China"},{"name":"Changchun Jingyuetan Remote Sensing Test Site, Changchun 130102, China"}]},{"given":"Xinbiao","family":"Li","sequence":"additional","affiliation":[{"name":"School of Geomatics and Prospecting Engineering, Jilin Jianzhu University, Changchun 130118, China"}]},{"given":"Tianhao","family":"Guo","sequence":"additional","affiliation":[{"name":"Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China"},{"name":"Changchun Jingyuetan Remote Sensing Test Site, Changchun 130102, China"}]},{"given":"Chunmei","family":"Wang","sequence":"additional","affiliation":[{"name":"Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, China"}]},{"given":"Xingming","family":"Zheng","sequence":"additional","affiliation":[{"name":"Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China"},{"name":"Changchun Jingyuetan Remote Sensing Test Site, Changchun 130102, China"}]}],"member":"1968","published-online":{"date-parts":[[2022,12,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"636","DOI":"10.1117\/12.7973877","article-title":"Speckle Suppression and Analysis for Synthetic Aperture Radar Images","volume":"25","author":"Lee","year":"1986","journal-title":"Opt. Eng."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"3834","DOI":"10.1109\/TCOMM.2020.2973976","article-title":"Joint Radar and Communication Design: Applications, State-of-the-Art, and the Road Ahead","volume":"68","author":"Liu","year":"2020","journal-title":"IEEE Trans. Commun."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Maity, A., Pattanaik, A., Sagnika, S., and Pani, S. (2015, January 12\u201313). A Comparative Study on Approaches to Speckle Noise Reduction in Images. Proceedings of the 1st International Conference on Computational Intelligence and Networks (CINE 2015), Bhubaneswar, India.","DOI":"10.1109\/CINE.2015.36"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"2232","DOI":"10.1109\/TGRS.2003.815240","article-title":"Polarimetric SAR Speckle Noise Model","volume":"41","year":"2003","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"244","DOI":"10.2747\/1548-1603.41.3.244","article-title":"Speckle Noise Reduction in SAR Imagery Using a Local Adaptive Median Filter","volume":"41","author":"Qiu","year":"2004","journal-title":"Gisci. Remote Sens."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"743","DOI":"10.1109\/JSTARS.2017.2768059","article-title":"A Review on Recent Developments in Fully Polarimetric SAR Image Despeckling","volume":"11","author":"Ma","year":"2018","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"253","DOI":"10.1016\/j.neucom.2022.04.066","article-title":"SAR-DRDNet: A SAR Image Despeckling Network with Detail Recovery","volume":"493","author":"Wu","year":"2022","journal-title":"Neurocomputing"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"108521","DOI":"10.1016\/j.sigpro.2022.108521","article-title":"A Systematic Review on Recent Developments in Nonlocal and Variational Methods for SAR Image Despeckling","volume":"196","author":"Baraha","year":"2022","journal-title":"Signal Process."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"226","DOI":"10.5589\/m07-023","article-title":"Polarimetric SAR Image Filtering with Trace-Based Partial Differential Equations","volume":"33","author":"Foucher","year":"2014","journal-title":"Can. J. Remote Sens."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Chan, D., Gambini, J., and Frery, A.C. (2022). Entropy-Based Non-Local Means Filter for Single-Look SAR Speckle Reduction. Remote Sens., 14.","DOI":"10.3390\/rs14030509"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Pang, Y., Jiang, S., Cheng, B., Liu, W., and Wu, Y. (2021, January 26\u201329). Design and Implement of Median Filter toward Remote Sensing Images Based on FPGA. Proceedings of the International Conference on ASIC, Kunming, China.","DOI":"10.1109\/ASICON52560.2021.9620528"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Yommy, A.S., Liu, R., Onuh, S.O., and Ikechukwu, A.C. (2015, January 14\u201316). SAR Image Despeckling and Compression Using K-Nearest Neighbour Based Lee Filter and Wavelet. Proceedings of the 2015 8th International Congress on Image and Signal Processing (CISP 2015), Shenyang, China.","DOI":"10.1109\/CISP.2015.7407868"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1097","DOI":"10.1109\/LGRS.2019.2939208","article-title":"Frost Filtering Algorithm of SAR Images with Adaptive Windowing and Adaptive Tuning Factor","volume":"17","author":"Sun","year":"2020","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2373","DOI":"10.1109\/36.964973","article-title":"Filtering of Multichannel SAR Images","volume":"39","author":"Quegan","year":"2001","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Lattari, F., Leon, B.G., Asaro, F., Rucci, A., Prati, C., and Matteucci, M. (2019). Deep Learning for SAR Image Despeckling. Remote Sens., 11.","DOI":"10.3390\/rs11131532"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"356","DOI":"10.1109\/7.53462","article-title":"A SAR Processor Based on Two-Dimensional FFT Codes","volume":"26","author":"Franceschetti","year":"1990","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"288","DOI":"10.1002\/mrm.1910210213","article-title":"Filtering Noise from Images with Wavelet Transforms","volume":"21","author":"Weaver","year":"1991","journal-title":"Magn. Reson. Med."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"851","DOI":"10.1109\/36.917910","article-title":"Toward Edge Sharpening: A SAR Speckle Filtering Algorithm","volume":"39","author":"Dong","year":"2001","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1953","DOI":"10.1109\/36.729367","article-title":"Analysis of Speckle Noise Contribution on Wavelet Decomposition of SAR Images","volume":"36","author":"Simard","year":"1998","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_20","unstructured":"(2022, December 18). Sentinel-1\u2014Overview\u2014Sentinel Online\u2014Sentinel Online. Available online: https:\/\/sentinels.copernicus.eu\/web\/sentinel\/missions\/sentinel-1\/overview."},{"key":"ref_21","unstructured":"(2022, October 02). Sentinel-1 Toolbox\u2014Sentinel Online. Available online: https:\/\/sentinel.esa.int\/web\/sentinel\/toolboxes\/sentinel-1."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"282","DOI":"10.1007\/978-3-642-02256-2_24","article-title":"Multiplicative Noise Cleaning via a Variational Method Involving Curvelet Coefficients","volume":"Volume 5567","author":"Durand","year":"2009","journal-title":"Scale Space and Variational Methods in Computer Vision"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Salehi, H., Vahidi, J., Abdeljawad, T., Khan, A., and Rad, S.Y.B. (2020). A SAR Image Despeckling Method Based on an Extended Adaptive Wiener Filter and Extended Guided Filter. Remote Sens., 12.","DOI":"10.3390\/rs12152371"},{"key":"ref_24","unstructured":"(2022, October 02). Marcoleonetti1 (2022). Speckle Autocorrelation\u2014File Exchange\u2014MATLAB Central. Available online: https:\/\/ww2.mathworks.cn\/matlabcentral\/fileexchange\/94765-speckle-autocorrelation?s_tid=srchtitle_speckle%20autocorrelation_1."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"191","DOI":"10.1007\/978-3-030-73616-3_14","article-title":"At Issue: The Gaussian Autocorrelation Function","volume":"153 LNCE","author":"Maes","year":"2021","journal-title":"Lect. Notes Civil Eng."},{"key":"ref_26","first-page":"9392648","article-title":"SAR Ship Image Speckle Noise Suppression Algorithm Based on Adaptive Bilateral Filter","volume":"2022","author":"Li","year":"2022","journal-title":"Wirel. Commun. Mob. Comput."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Rubel, O., Lukin, V., Rubel, A., and Egiazarian, K. (2021). Selection of Lee Filter Window Size Based on Despeckling Efficiency Prediction for Sentinel SAR Images. Remote Sens., 13.","DOI":"10.3390\/rs13101887"},{"key":"ref_28","first-page":"1054","article-title":"Statistical Analysis of Speckle Noise Reduction in C-Band SAR Image Using FFT Based Circular Pass Filter And Circular Cut Filter","volume":"25","year":"2021","journal-title":"Ann. Rom. Soc. Cell Biol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1016\/j.softx.2017.11.005","article-title":"Short-Time Fourier Transform with the Window Size Fixed in the Frequency Domain (STFT-FD): Implementation","volume":"8","author":"Mateo","year":"2018","journal-title":"SoftwareX"}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/15\/1\/247\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:49:24Z","timestamp":1760147364000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/15\/1\/247"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,12,31]]},"references-count":29,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2023,1]]}},"alternative-id":["rs15010247"],"URL":"https:\/\/doi.org\/10.3390\/rs15010247","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2022,12,31]]}}}