{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T01:11:32Z","timestamp":1760231492893,"version":"build-2065373602"},"reference-count":30,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2022,9,21]],"date-time":"2022-09-21T00:00:00Z","timestamp":1663718400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003725","name":"National Research Foundation (NRF) of Korea funded by the Ministry of Science and ICT","doi-asserted-by":"publisher","award":["2022R1A5A7000765","NRF-2022R1A2C2010298"],"award-info":[{"award-number":["2022R1A5A7000765","NRF-2022R1A2C2010298"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003725","name":"Basic Science Research Program through the National Research Foundation (NRF) of Korea funded by the Ministry of Education","doi-asserted-by":"publisher","award":["2022R1A5A7000765","NRF-2022R1A2C2010298"],"award-info":[{"award-number":["2022R1A5A7000765","NRF-2022R1A2C2010298"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A channel modeling method and deep-learning-based symbol decision method are proposed to improve the performance of a visual MIMO system for communication between a variable-color LED array and camera. Although image processing algorithms using color clustering are available to correct distorted color information in a channel, color-similarity-based approaches are limited by real-world distortions; to overcome such limitations, symbol decision is defined as a multiclass classification problem. Further, to learn a robust classifier against channel distortion, a deep neural network learning technique is applied to adaptively determine symbols from channel distortion. The network designed herein comprises the channel identification and symbol decision modules; the channel identification module extracts a channel identification vector for symbol determination from an input image using a two-dimensional deep convolutional neural network (CNN); the symbol decision module then generates a feature map by combining the channel identification vector and information on adjacent symbols to determine the symbol via learning correlations between adjacent symbols using a one-dimensional CNN. The two modules are connected together and learned simultaneously in an end-to-end manner. We also propose a new channel modeling method that intuitively reflects real-world distortion factors rather than the conventional additive white Gaussian noise channel to efficiently train deep-learning networks. Lastly, in the proposed channel distortion environment, the proposed method shows performance improvement by an average of about 41.8% (up to about 54.8%) compared to the existing Euclidean distance method, and about 6.3% (up to about 9.2%) on average compared to the SVM method.<\/jats:p>","DOI":"10.3390\/s22197176","type":"journal-article","created":{"date-parts":[[2022,9,22]],"date-time":"2022-09-22T23:07:55Z","timestamp":1663888075000},"page":"7176","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Deep-Learning-Based Adaptive Symbol Decision for Visual MIMO System with Variable Channel Modeling"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5170-2676","authenticated-orcid":false,"given":"Jai-Eun","family":"Kim","sequence":"first","affiliation":[{"name":"Department of Electronic Engineering, Kookmin University, Seongbuk-gu, Seoul 136-702, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6784-5591","authenticated-orcid":false,"given":"Tae-Ho","family":"Kwon","sequence":"additional","affiliation":[{"name":"Department of Electronic Engineering, Kookmin University, Seongbuk-gu, Seoul 136-702, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5052-3844","authenticated-orcid":false,"given":"Ki-Doo","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Electronic Engineering, Kookmin University, Seongbuk-gu, Seoul 136-702, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,9,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2047","DOI":"10.1109\/COMST.2015.2476474","article-title":"Visible Light Communication, Networking, and Sensing: A Survey, Potential and Challenges","volume":"17","author":"Pathak","year":"2015","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"3393","DOI":"10.1093\/ietcom\/e89-b.12.3393","article-title":"Experimental Investigation of Modulation Method for Visible-Light Communications","volume":"E89-B","author":"Sugiyama","year":"2006","journal-title":"IEICE Trans. Commun."},{"key":"ref_3","unstructured":"Yokoi, A. (2008). Color multiplex coding for VLC. IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs), Samsung Yokohama Research Institute."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"139","DOI":"10.5121\/ijcnc.2015.7610","article-title":"An Overview of Visible Light Communication Systems","volume":"7","author":"Cevik","year":"2015","journal-title":"Int. J. Comput. Netw. Commun."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"163176","DOI":"10.1016\/j.ijleo.2019.163176","article-title":"Exploiting novel concepts for visible light communications: From light-based IoT to living surfaces","volume":"195","author":"Katz","year":"2019","journal-title":"Optik"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Warmerdam, K., Pandharipande, A., and Caicedo, D. (2015, January 10\u201312). Connectivity in IoT indoor lighting systems with visible light communications. Proceedings of the 2015 IEEE Online Conference on Green Communications (OnlineGreenComm), Piscataway, NJ, USA.","DOI":"10.1109\/OnlineGreenCom.2015.7387378"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1016\/j.optcom.2012.07.083","article-title":"Color-independent VLC based on a color space without sending target color information","volume":"286","author":"Das","year":"2013","journal-title":"Opt. Commun."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Yuan, W., Dana, K., Varga, M., Ashok, A., Gruteser, M., and Mandayam, N. (2011, January 20\u201325). Computer vision methods for visual MIMO optical system. Proceedings of the CVPR 2011 Workshops, Colorado Springs, CO, USA.","DOI":"10.1109\/CVPRW.2011.5981735"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"665","DOI":"10.1007\/s11277-013-1312-8","article-title":"Performance analysis of color-independent visible light communication using a color-space-based constellation diagram and modulation scheme","volume":"74","author":"Das","year":"2014","journal-title":"Wirel. Pers. Commun."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.optcom.2013.04.002","article-title":"Performance improvement of color space based VLC modulation schemes under color and intensity variation","volume":"303","author":"Das","year":"2013","journal-title":"Opt. Commun."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Ashokz, A., Gruteserz, M., Mandayamz, N., and Dana, K. (2011, January 23\u201325). Characterizing Multiplexing and Diversity in Visual MIMO. Proceedings of the 2011 45th Annual Conference on Information Sciences and Systems (CISS), Baltimore, MD, USA.","DOI":"10.1109\/CISS.2011.5766257"},{"key":"ref_12","unstructured":"Hu, W., Gu, H., and Pu, Q. (October, January 30). Lightsync: Unsynchronizedvisual communication over screen-camera links. Proceedings of the 19th Annual International Conference on Mobile Computing Networking, MobiCom\u201913, New York, NY, USA."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Hu, W., Mao, J., Huang, Z., Xue, Y., She, J., Bian, K., and Shen, G. (2014, January 7\u201311). Strata: Layered coding for scalablevisual communication. Proceedings of the 20th Annual International Conference on Mobile Computing and Networking, MobiCom\u201914, New York, NY, USA.","DOI":"10.1145\/2639108.2639132"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Kim, J.-E., Kim, J.-W., Park, Y., and Kim, K.-D. (2016). Color-Space-Based Visual-MIMO for V2X Communication. Sensors, 16.","DOI":"10.3390\/s16040591"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Kwon, T.-H., Kim, J.-E., Kim, Y.-H., and Kim, K.-D. (2018). Color-Independent Visible Light Communications Based on Color Space: State of the Art and Potentials. Electronics, 7.","DOI":"10.3390\/electronics7090190"},{"key":"ref_16","unstructured":"Kim, J.-E., Kim, J.-W., Park, Y., and Kim, K.-D. (2015, January 7\u201310). Applicability of color-independent visual-MIMO for V2X communication. Proceedings of the 2015 Seventh International Conference on Ubiquitous and Future Networks (ICUFN), Sapporo, Japan."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Kim, J.-E., and Kim, K.-D. (2017, January 11\u201313). Symbol decision method of color-independent visual-MIMO system using a dynamic palette. Proceedings of the 2017 23rd Asia-Pacific Conference on Communications (APCC), Perth, Australia.","DOI":"10.23919\/APCC.2017.8303996"},{"key":"ref_18","first-page":"2418","article-title":"Performance Improvement of Color-Independent Visual-MIMO System Using Color Quantization Based Palette","volume":"42","author":"Aldhahi","year":"2017","journal-title":"JKICS"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Dollar, P., Wojek, C., Schiele, B., and Perona, P. (2009, January 20\u201325). Pedestrian Detection: A Benchmark. Proceedings of the 2009 IEEE Conference on Computer Vision and Pattern Recognition, Miami, FL, USA.","DOI":"10.1109\/CVPR.2009.5206631"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"541","DOI":"10.1162\/neco.1989.1.4.541","article-title":"Backpropagation applied to handwritten zip code recognition","volume":"1","author":"LeCun","year":"1989","journal-title":"Neural Comput."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2278","DOI":"10.1109\/5.726791","article-title":"Gradient based learning applied to document recognition","volume":"86","author":"LeCun","year":"1998","journal-title":"Proc. IEEE"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"84","DOI":"10.1145\/3065386","article-title":"ImageNet classification with deep convolutional neural networks","volume":"60","author":"Krizhevsky","year":"2017","journal-title":"Commun. ACM"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Szegedy, C., Liu, W., Jia, Y., Sermanet, P., Reed, S., Anguelov, D., Erhan, D., Vanhoucke, V., and Rabinovich, A. (2015, January 7\u201312). Going deeper with convolutions. Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), Boston, MA, USA.","DOI":"10.1109\/CVPR.2015.7298594"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Long, J., Shelhamer, E., and Darrell, T. (2015, January 7\u201312). Fully Convolutional Networks for Semantic Segmentation. Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), Boston, MA, USA.","DOI":"10.1109\/CVPR.2015.7298965"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"2481","DOI":"10.1109\/TPAMI.2016.2644615","article-title":"SegNet: A Deep Convolutional Encoder-Decoder Architecture for Image Segmentation","volume":"39","author":"Badrinarayanan","year":"2017","journal-title":"IEEE Trans. Pattern Anal. Mach. Intell."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Kim, J.-E., Kim, J.-W., and Kim, K.-D. (2016). LEA Detection and Tracking Method for Color-Independent Visual-MIMO. Sensors, 16.","DOI":"10.3390\/s16071027"},{"key":"ref_27","unstructured":"Kim, J.-E. (2015). The Performance Analysis of Color Independent Visual-MIMO based on Color Space. [Master\u2019s Thesis, Kookmin University]."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"20","DOI":"10.1145\/965139.807362","article-title":"Color spaces for computer graphics","volume":"12","author":"Joblove","year":"1978","journal-title":"ACM SIGGRAPH Comput. Graph."},{"key":"ref_29","unstructured":"Berns, R.S. (2000). Principles of Color Technology, John Wiley&Sons."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1109\/5254.708428","article-title":"Support vector machines","volume":"13","author":"Hearst","year":"1998","journal-title":"IEEE Intell. Syst. Appl."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/19\/7176\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T00:36:56Z","timestamp":1760143016000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/19\/7176"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,9,21]]},"references-count":30,"journal-issue":{"issue":"19","published-online":{"date-parts":[[2022,10]]}},"alternative-id":["s22197176"],"URL":"https:\/\/doi.org\/10.3390\/s22197176","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2022,9,21]]}}}