{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,12]],"date-time":"2026-04-12T18:29:24Z","timestamp":1776018564839,"version":"3.50.1"},"reference-count":29,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2020,4,7]],"date-time":"2020-04-07T00:00:00Z","timestamp":1586217600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Synthetic Aperture Radar (SAR) polarimetric datasets are widely used in the detection and classification of urban areas. Most methods used today are based on the decomposition of fully polarimetric SAR data, which allows for the extraction of physical information about the nature of the medium and the application of proper classification methods. According to the theory, the main and predominant backscattering mechanism for buildings is double bounce. However, when analyzing urban environments, the observed predominant backscatter may differ from theory depending on many aspects. In this paper, we analyze fully polarimetric ALOS PALSAR data for various cities located on different continents, proving that the theory does not hold for most cases. There are many factors that have an impact on the detected backscatter mechanism, and the theoretical principle of predominant double bounce in urban areas can be met only under specific conditions. These factors are, among others, the orientation of the buildings, the dimensions of the streets, the type of construction (i.e., numerous planes on the roof), etc. This paper also mentions the canonical example of San Francisco, widely analyzed in the literature, as a case showing the impact of building deorientation on double bounce scattering. This area of interest is also discussed in terms of the impact of SAR data resolution on the detection of specific backscatter mechanisms. The findings of this work are very useful for increasing the awareness of the utilization of classification approaches where only pixels with double bounce backscatter mechanisms are classified as urban areas. Moreover, the article lists factors that should be taken into consideration when performing urban area detection based only on polarimetric data and standard algorithms, such as street and building orientation, building heights, and structures.<\/jats:p>","DOI":"10.3390\/rs12071187","type":"journal-article","created":{"date-parts":[[2020,4,8]],"date-time":"2020-04-08T05:59:47Z","timestamp":1586325587000},"page":"1187","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Effects on the Double Bounce Detection in Urban Areas Based on SAR Polarimetric Characteristics"],"prefix":"10.3390","volume":"12","author":[{"given":"Jos\u00e9 Manuel","family":"Delgado Blasco","sequence":"first","affiliation":[{"name":"RHEA Group, Via di Grotta Portella 6\/8, 00044 Frascati, Italy"},{"name":"Grupo de Investigaci\u00f3n Microgeodesia Ja\u00e9n (PAIDI RNM-282), Universidad de Ja\u00e9n, Campus Las Lagunillas s\/n, 23071 Ja\u00e9n, Spain"}]},{"given":"Magdalena","family":"Fitrzyk","sequence":"additional","affiliation":[{"name":"RSAC c\/o ESA-ESRIN, Largo Galileo Galilei 1, 00044 Frascati, Italy"}]},{"given":"Jolanda","family":"Patruno","sequence":"additional","affiliation":[{"name":"RHEA Group, Via di Grotta Portella 6\/8, 00044 Frascati, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1798-7521","authenticated-orcid":false,"given":"Antonio Miguel","family":"Ruiz-Armenteros","sequence":"additional","affiliation":[{"name":"Grupo de Investigaci\u00f3n Microgeodesia Ja\u00e9n (PAIDI RNM-282), Universidad de Ja\u00e9n, Campus Las Lagunillas s\/n, 23071 Ja\u00e9n, Spain"},{"name":"Dpto. Ingenier\u00eda Cartogr\u00e1fica, Geod\u00e9sica y Fotogrametr\u00eda, Universidad de Ja\u00e9n, EPSJ, Campus Las Lagunillas s\/n, Edif. A3, 23071 Ja\u00e9n, Spain"},{"name":"Centro de Estudios Avanzados en Ciencias de la Tierra, Energ\u00eda y Medio Ambiente CEACTEMA, Universidad de Ja\u00e9n, Campus Las Lagunillas, s\/n, 23071 Ja\u00e9n, Spain"}]},{"given":"Mattia","family":"Marconcini","sequence":"additional","affiliation":[{"name":"German Aerospace Center (DLR), Oberpfaffenhofen, 82234 Wessling, Germany"}]}],"member":"1968","published-online":{"date-parts":[[2020,4,7]]},"reference":[{"key":"ref_1","unstructured":"Lee, J.-S., and Pottier, E. (2009). Polarimetric Radar Imaging: From Basics to Applications, CRC Press."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Patruno, J., Fitrzyk, M., and Delgado Blasco, J.M. (2019). Monitoring and detecting archaeological features with multi-frequency polarimetric analysis. Remote Sens., 12.","DOI":"10.3390\/rs12010001"},{"key":"ref_3","first-page":"68","article-title":"An entropy based classification scheme for land applications of polarimetric SAR","volume":"35","author":"Cloude","year":"1997","journal-title":"Entropy"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"963","DOI":"10.1109\/36.673687","article-title":"A three-component scattering model for polarimetric SAR data","volume":"36","author":"Freeman","year":"1998","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1699","DOI":"10.1109\/TGRS.2005.852084","article-title":"Four-component scattering model for polarimetric SAR image decomposition","volume":"43","author":"Yamaguchi","year":"2005","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1278","DOI":"10.1109\/TGRS.2017.2750211","article-title":"Polarimetric phase and implications for urban classification","volume":"56","author":"Atwood","year":"2017","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Yamaguchi, Y., Yajima, Y., and Yamada, H. (2006). A four-component decomposition of POLSAR images based on the coherency matrix. IEEE Geosci. Remote Sens. Lett., 3.","DOI":"10.1109\/LGRS.2006.869986"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1090","DOI":"10.1109\/LGRS.2011.2157078","article-title":"Four-component decomposition of polarimetric SAR images with deorientation","volume":"8","author":"An","year":"2011","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Pottier, E., and Ferro-Famil, L. (2012, January 22\u201327). PolSARPro V5. 0: An ESA educational toolbox used for self-education in the field of POLSAR and POL-INSAR data analysis. Proceedings of the 2012 the IEEE International Geoscience and Remote Sensing Symposium, Munich, Germany.","DOI":"10.1109\/IGARSS.2012.6351925"},{"key":"ref_10","unstructured":"Pottier, E., and Lee, J.-S. (1999, January 26\u201329). Application of the <H\/A\/alpha> polarimetric decomposition theorem for unsupervised classification of fully polarimetric SAR data based on the wishart distribution. Proceedings of the SAR Workshop: CEOS Committee on Earth Observation Satellites, Toulouse, France."},{"key":"ref_11","unstructured":"Du, L.J., and Lee, J.S. (1996, January 31). Polarimetric SAR image classification based on target decomposition theorem and complex Wishart distribution. Proceedings of the IGARSS\u201996. 1996 International Geoscience and Remote Sensing Symposium, Lincoln, NE, USA."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Tan, C.P., Lim, K.S., and Ewe, H.T. (2007, January 27\u201329). Image processing in polarimetric SAR images using a hybrid entropy decomposition and maximum likelihood (EDML). Proceedings of the 2007 5th International Symposium on Image and Signal Processing and Analysis, Istanbul, Turkey.","DOI":"10.1109\/ISPA.2007.4383730"},{"key":"ref_13","unstructured":"Pottier, E. (1994, January 8\u201312). Radar target decomposition theorems and unsupervized classification of full polarimetric SAR data. Proceedings of the IGARSS\u201994-1994 IEEE International Geoscience and Remote Sensing Symposium, Pasadena, CA, USA."},{"key":"ref_14","unstructured":"Fang, C., Wen, H., and Yirong, W. (2006, January 16\u201319). An improved Cloude-Pottier decomposition using H\/\u03b1\/span and complex Wishart classifier for polarimetric SAR classification. Proceedings of the 2006 CIE international conference on radar, Shanghai, China."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"4710","DOI":"10.1016\/j.eswa.2011.09.082","article-title":"Evolutionary RBF classifier for polarimetric SAR images","volume":"39","author":"Ince","year":"2012","journal-title":"Expert Syst. Appl."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2583","DOI":"10.1109\/JSTARS.2016.2527242","article-title":"Extraction of urban areas from polarimetric SAR imagery","volume":"9","author":"Azmedroub","year":"2016","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2249","DOI":"10.1109\/36.789621","article-title":"Unsupervised classification using polarimetric decomposition and complex Wishart classifier","volume":"37","author":"Lee","year":"1999","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"2299","DOI":"10.1080\/01431169408954244","article-title":"Classification of multi-look polarimetric SAR imagery based on complex Wishart distribution","volume":"15","author":"Lee","year":"1994","journal-title":"Int. J. Remote Sens."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"835","DOI":"10.1080\/01431169208904157","article-title":"Bayesian classification of polarimetric SAR images using adaptive a priori probabilities","volume":"13","author":"Burnette","year":"1992","journal-title":"Int. J. Remote Sens."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Ergen, M. (2018). Characteristics of urban agglomeration in different continents: History, patterns, dynamics, drivers and trends, urban agglomeration. Urban Agglomeration, IntechOpen.","DOI":"10.5772\/intechopen.70025"},{"key":"ref_21","unstructured":"Marconcini, M., Gorelick, N., Metz-Marconcini, A., and Esch, T. (2018, January 10\u201314). Mapping the global settlement growth from 1985 to 2015-the world settlement footprint evolution dataset. Proceedings of the AGU Fall Meeting Abstracts, Washington, DC, USA."},{"key":"ref_22","unstructured":"Marconcini, M., Gorelick, N., Metz-Marconcini, A., and Esch, T. (2019). Accurately monitoring urbanization at global scale \u2013 the world settlement footprint. Proceedings of the 20th World Bank Conference on Land and Poverty, Washington, DC, USA, 25\u201329 March 2019, World Bank."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"469","DOI":"10.1007\/s11442-007-0469-z","article-title":"Measuring urban sprawl in Beijing with geo-spatial indices","volume":"17","author":"Jiang","year":"2007","journal-title":"J. Geogr. Sci."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Chan, C.-S., Dang, A., Tong, Z.A., and Tong, Z. (2005). A 3D model of the inner city of Beijing. Computer Aided Architectural Design Futures 2005, Springer.","DOI":"10.1007\/1-4020-3698-1_5"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Goldfield, D. (2006). Encyclopedia of American Urban History, Sage Publications.","DOI":"10.4135\/9781412952620"},{"key":"ref_26","first-page":"133","article-title":"Change in the urban spatial structure of the Greater Cairo metropolitan area, Egypt","volume":"XXXVIII","author":"Hassan","year":"2011","journal-title":"Archives"},{"key":"ref_27","unstructured":"Gorelick, N. (2012, January 3\u20137). Google earth engine. Proceedings of the AGU Fall Meeting Abstracts, San Francisco, CA, USA."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1016\/j.rse.2017.06.031","article-title":"Google Earth Engine: Planetary-scale geospatial analysis for everyone","volume":"202","author":"Gorelick","year":"2017","journal-title":"Remote Sens. Environ."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"4687","DOI":"10.1109\/TGRS.2015.2406793","article-title":"The characteristics of the multipath scattering and the application for geometry extraction in high-resolution SAR images","volume":"53","author":"Zhang","year":"2015","journal-title":"IEEE Trans. Geosci. Remote Sens."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/12\/7\/1187\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T09:16:22Z","timestamp":1760174182000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/12\/7\/1187"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,4,7]]},"references-count":29,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2020,4]]}},"alternative-id":["rs12071187"],"URL":"https:\/\/doi.org\/10.3390\/rs12071187","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,4,7]]}}}