{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:15:52Z","timestamp":1760242552594,"version":"build-2065373602"},"reference-count":69,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2017,11,6]],"date-time":"2017-11-06T00:00:00Z","timestamp":1509926400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>Recently, many studies have actively dealt with the issue of driver-gaze tracking for monitoring the forward gaze and physical condition. Driver-gaze tracking is an effective method of measuring a driver\u2019s inattention that is one of the major causes of traffic accidents. Among many gaze-tracking methods, the corneal specular reflection (SR)-based method becomes ineffective, unlike in an indoor environment, when a driver\u2019s head rotates, which makes SR disappear from input images or disperses SR in the lachrymal gland or eyelid, thereby increasing the gaze-tracking error. Besides, since a driver\u2019s eyes in a vehicle environment need to be captured in a wide range covering his head rotation, the eye region is captured in a relatively low resolution compared to face-only images taken in indoor environments at the same resolution, making pupil and corneal SR difficult to detect accurately. To solve these problems, we propose a fuzzy-system-based method for detecting a driver\u2019s pupil and corneal SR for gaze tracking in a vehicle environment. Unlike existing studies detecting pupil and corneal SR in both eyes, the method proposed in this research uses the results of a fuzzy system based on two features considering the symmetrical characteristics of face and facial feature points to determine the status of a driver\u2019s head rotation. Based on the output of the fuzzy system, the proposed method excludes the eye region, which is very likely to have a high error rate of detection due to excessive head rotation, from the detection process of the pupil and corneal SR. Accordingly, the proposed method detects pupil and corneal SR only in the eye region that apparently has a low detection error rate, thereby achieving accurate detection. We use 20,654 images capturing 15 subjects (including subjects wearing glasses), who gaze at pre-set fifteen regions in a vehicle, to measure the detection accuracy of the pupil and corneal SR for each region and the gaze tracking accuracy. Our experimental results show that the proposed method performs better than existing methods.<\/jats:p>","DOI":"10.3390\/sym9110267","type":"journal-article","created":{"date-parts":[[2017,11,6]],"date-time":"2017-11-06T11:39:38Z","timestamp":1509968378000},"page":"267","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Fuzzy-System-Based Detection of Pupil Center and Corneal Specular Reflection for a Driver-Gaze Tracking System Based on the Symmetrical Characteristics of Face and Facial Feature Points"],"prefix":"10.3390","volume":"9","author":[{"given":"Dong","family":"Lee","sequence":"first","affiliation":[{"name":"Division of Electronics and Electrical Engineering, Dongguk University, 30 Pildong-ro 1-gil, Jung-gu, Seoul 100-715, Korea"}]},{"given":"Hyo","family":"Yoon","sequence":"additional","affiliation":[{"name":"Division of Electronics and Electrical Engineering, Dongguk University, 30 Pildong-ro 1-gil, Jung-gu, Seoul 100-715, Korea"}]},{"given":"Hyung","family":"Hong","sequence":"additional","affiliation":[{"name":"Division of Electronics and Electrical Engineering, Dongguk University, 30 Pildong-ro 1-gil, Jung-gu, Seoul 100-715, Korea"}]},{"given":"Kang","family":"Park","sequence":"additional","affiliation":[{"name":"Division of Electronics and Electrical Engineering, Dongguk University, 30 Pildong-ro 1-gil, Jung-gu, Seoul 100-715, Korea"}]}],"member":"1968","published-online":{"date-parts":[[2017,11,6]]},"reference":[{"key":"ref_1","unstructured":"Singh, S. (2015). Critical Reasons for Crashes Investigated in the National Motor Vehicle Crash Causation Survey, Traffic Safety Facts Crash Stats. Report No. DOT HS 812 115."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Li, Z., Li, S.E., Li, R., Cheng, B., and Shi, J. (2017). Online detection of driver fatigue using steering wheel angles for real driving conditions. Sensors, 17.","DOI":"10.3390\/s17030495"},{"key":"ref_3","first-page":"504","article-title":"Head pose and eye state monitoring (HEM) for driver drowsiness detection: Overview","volume":"1","author":"Diddi","year":"2014","journal-title":"Int. J. Innov. Sci. Eng. Technol."},{"key":"ref_4","unstructured":"Schneider, E., Dera, T., Bartl, K., Boening, G., Bardins, S., and Brandt, T. (2005, January 10\u201312). Eye movement driven head-mounted camera: It looks where the eyes look. Proceedings of the IEEE International Conference on Systems, Man and Cybernetics, Waikoloa, HI, USA."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1052","DOI":"10.1109\/TVT.2004.830974","article-title":"Real-time nonintrusive monitoring and prediction of driver fatigue","volume":"53","author":"Ji","year":"2004","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"478","DOI":"10.1109\/TPAMI.2009.30","article-title":"In the eye of the beholder: A survey of models for eyes and gaze","volume":"32","author":"Hansen","year":"2010","journal-title":"IEEE Trans. Pattern Anal. Mach. Intell."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1124","DOI":"10.1109\/TBME.2005.863952","article-title":"General theory of remote gaze estimation using the pupil center and corneal reflections","volume":"53","author":"Guestrin","year":"2006","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"52","DOI":"10.1016\/j.cviu.2004.07.005","article-title":"A non-contact device for tracking gaze in a human computer interface","volume":"98","author":"Noureddin","year":"2005","journal-title":"Comput. Vis. Image Underst."},{"key":"ref_9","unstructured":"Morimoto, C.H., Koons, D., Amir, A., Flickner, M., and Zhai, S. (1999, January 17\u201320). Keeping an eye for HCI. Proceedings of the 12th Brazilian Symposium on Computer Graphics and Image Processing, Campinas, Brazil."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1016\/j.cviu.2004.07.011","article-title":"A novel non-intrusive eye gaze estimation using cross-ratio under large head motion","volume":"98","author":"Yoo","year":"2005","journal-title":"Comput. Vis. Image Underst."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"053111-1","DOI":"10.1117\/1.OE.53.5.053111","article-title":"Binocular gaze detection method using a fuzzy algorithm based on quality measurements","volume":"53","author":"Cho","year":"2014","journal-title":"Opt. Eng."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"4","DOI":"10.1016\/j.cviu.2004.07.010","article-title":"Eye gaze tracking techniques for interactive applications","volume":"98","author":"Morimoto","year":"2005","journal-title":"Comput. Vis. Image Underst."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"234","DOI":"10.1109\/TSMCB.2003.811128","article-title":"A novel approach to 3-D gaze tracking using stereo cameras","volume":"34","author":"Shih","year":"2004","journal-title":"IEEE Trans. Syst. Man Cybern. Part B"},{"key":"ref_14","unstructured":"(2017, March 07). Tobii. Available online: http:\/\/www.tobii.com."},{"key":"ref_15","unstructured":"(2017, March 07). SMI. Available online: http:\/\/www.smivision.com\/."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2246","DOI":"10.1109\/TBME.2007.895750","article-title":"Novel eye gaze tracking techniques under natural head movement","volume":"54","author":"Zhu","year":"2007","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Ohno, T., and Mukawa, N. (2004, January 22\u201324). A free-head, simple calibration, gaze tracking system that enables gaze-based interaction. Proceedings of the Symposium on Eye Tracking Research & Applications, San Antonio, TX, USA.","DOI":"10.1145\/968363.968387"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"799","DOI":"10.1016\/S0923-5965(98)00044-7","article-title":"Eye and gaze tracking for visually controlled interactive stereoscopic displays","volume":"14","author":"Talmi","year":"1999","journal-title":"Signal Process. Image Commun."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"3432","DOI":"10.1109\/TBME.2013.2266413","article-title":"Long-range gaze tracking system for large movements","volume":"60","author":"Cho","year":"2013","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_20","first-page":"446","article-title":"A real-time compensation strategy for non-contact gaze tracking under natural head movement","volume":"19","author":"Huang","year":"2010","journal-title":"Chin. J. Electron."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"5935","DOI":"10.3390\/s150305935","article-title":"A new gaze estimation method considering external light","volume":"15","author":"Lee","year":"2015","journal-title":"Sensors"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2577","DOI":"10.1109\/TCE.2010.5681143","article-title":"Gaze tracking system at a distance for controlling IPTV","volume":"56","author":"Lee","year":"2010","journal-title":"IEEE Trans. Consum. Electron."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Jung, D., Lee, J.M., Gwon, S.Y., Pan, W., Lee, H.C., Park, K.R., and Kim, H.-C. (2016). Compensation method of natural head movement for gaze tracking system using an ultrasonic sensor for distance measurement. Sensors, 16.","DOI":"10.3390\/s16010110"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"663","DOI":"10.1016\/j.imavis.2005.06.001","article-title":"Eye tracking: Pupil orientation geometrical modeling","volume":"24","author":"Villanueva","year":"2006","journal-title":"Image Vis. Comput."},{"key":"ref_25","first-page":"753","article-title":"Non-intrusive gaze tracking using artificial neural networks","volume":"6","author":"Baluja","year":"1993","journal-title":"Adv. Neural Inf. Process. Syst."},{"key":"ref_26","unstructured":"Williams, O., Blake, A., and Cipolla, R. (2006, January 17\u201322). Sparse and semi-supervised visual mapping with the S3GP. Proceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition, New York, NY, USA."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Xu, L.-Q., Machin, D., and Sheppard, P. (1998, January 14\u201317). A novel approach to real- time non-intrusive gaze finding. Proceedings of the British Machine Vision Conference, Southampton, UK.","DOI":"10.5244\/C.12.43"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"331","DOI":"10.1016\/S0262-8856(99)00053-0","article-title":"Pupil detection and tracking using multiple light sources","volume":"18","author":"Morimoto","year":"2000","journal-title":"Image Vis. Comput."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Bozomitu, R.G., P\u0103s\u0103ric\u0103, A., Cehan, V., Rotariu, C., and Barabasa, C. (2015, January 6\u201310). Pupil centre coordinates detection using the circular Hough transform technique. Proceedings of the 38th IEEE International Spring Seminar on Electronics Technology, Eger, Hungary.","DOI":"10.1109\/ISSE.2015.7248041"},{"key":"ref_30","unstructured":"Leimberg, D., Vester-Christensen, M., Ersb\u00f8ll, B.K., and Hansen, L.K. (2005, January 10\u201311). Heuristics for speeding up gaze estimation. Proceedings of the Svenska Symposium i Bildanalys, Malm\u00f8, Sweden."},{"key":"ref_31","unstructured":"Hansen, D.W., and Pece, A.E.C. (2003, January 17). Iris tracking with feature free contours. Proceedings of the IEEE International Workshop on Analysis and Modeling of Faces and Gestures, Nice, France."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"145","DOI":"10.1016\/S0169-2607(98)00105-9","article-title":"Robust pupil center detection using a curvature algorithm","volume":"59","author":"Zhu","year":"1999","journal-title":"Comput. Methods Programs Biomed."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"476","DOI":"10.1109\/34.765658","article-title":"Direct least square fitting of ellipses","volume":"21","author":"Fitzgibbon","year":"1999","journal-title":"IEEE Trans. Pattern Anal. Mach. Intell."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"965","DOI":"10.1109\/TITS.2013.2247759","article-title":"A gaze-based driver distraction warning system and its effect on visual behavior","volume":"14","author":"Ahlstrom","year":"2013","journal-title":"IEEE Trans. Intell. Transp. Syst."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"340","DOI":"10.1109\/TITS.2007.895298","article-title":"Real-time detection of driver cognitive distraction using support vector machines","volume":"8","author":"Liang","year":"2007","journal-title":"IEEE Trans. Intell. Transp. Syst."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Tawari, A., and Trivedi, M.M. (2014, January 8\u201311). Robust and continuous estimation of driver gaze zone by dynamic analysis of multiple face videos. Proceedings of the IEEE Intelligent Vehicles Symposium, Dearborn, MI, USA.","DOI":"10.1109\/IVS.2014.6856607"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1109\/TITS.2003.821342","article-title":"Determining driver visual attention with one camera","volume":"4","author":"Smith","year":"2003","journal-title":"IEEE Trans. Intell. Transp. Syst."},{"key":"ref_38","unstructured":"Smith, P., Shah, M., and da Vitoria Lobo, N. (2000, January 3\u20137). Monitoring head\/eye motion for driver alertness with one camera. Proceedings of the International Conference on Pattern Recognition, Barcelona, Spain."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Bergen, J.R., Anandan, P., Hanna, K.J., and Hingorani, R. (1992, January 19\u201322). Hierarchical model-based motion estimation. Proceedings of the European Conference on Computer Vision, Santa Margherita Ligure, Italy.","DOI":"10.1007\/3-540-55426-2_27"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"2014","DOI":"10.1109\/TITS.2015.2396031","article-title":"Driver gaze tracking and eyes off the road detection system","volume":"16","author":"Vicente","year":"2015","journal-title":"IEEE Trans. Intell. Transp. Syst."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Batista, J.P. (2005, January 7\u20139). A real-time driver visual attention monitoring system. Proceedings of the 2nd Iberian Conference on Pattern Recognition and Image Analysis, Estoril, Portugal.","DOI":"10.1007\/11492429_25"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"308","DOI":"10.1049\/iet-cvi.2015.0296","article-title":"\u201cOwl\u201d and \u201cLizard\u201d: Patterns of head pose and eye pose in driver gaze classification","volume":"10","author":"Fridman","year":"2016","journal-title":"IET Comput. Vis."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"411","DOI":"10.1109\/TBME.2010.2087330","article-title":"Iris center corneal reflection method for gaze tracking using visible light","volume":"58","author":"Sigut","year":"2011","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_44","unstructured":"(2017, September 11). ELP-USB500W02M-L36. Available online: http:\/\/www.elpcctv.com\/5mp-ultra-wide-angle-hd-usb-camera-board-with-mpeg-format-p-83.html."},{"key":"ref_45","unstructured":"(2017, September 11). 850 nm CWL, 10 nm FWHM, 25 mm Mounted Diameter. Available online: https:\/\/www.edmundoptics.com\/optics\/optical-filters\/bandpass-filters\/850nm-cwl-10nm-fwhm-25mm-mounted-diameter."},{"key":"ref_46","unstructured":"Dlib C++ Library (2017, March 07). Real-Time Face Pose Estimation. Available online: http:\/\/blog.dlib.net\/2014\/08\/real-time-face-pose-estimation.html."},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Kazemi, V., and Sullivan, J. (2014, January 23\u201328). One millisecond face alignment with an ensemble of regression trees. Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, Columbus, OH, USA.","DOI":"10.1109\/CVPR.2014.241"},{"key":"ref_48","unstructured":"Zhao, J., and Bose, B.K. (2002, January 5\u20138). Evaluation of membership functions for fuzzy logic controlled induction motor drive. Proceedings of the IEEE Annual Conference of the Industrial Electronics Society, Sevilla, Spain."},{"key":"ref_49","doi-asserted-by":"crossref","unstructured":"Bayu, B.S., and Miura, J. (2013, January 7\u20139). Fuzzy-based illumination normalization for face recognition. Proceedings of the IEEE Workshop on Advanced Robotics and Its Social Impacts, Tokyo, Japan.","DOI":"10.1109\/ARSO.2013.6705518"},{"key":"ref_50","first-page":"164","article-title":"Why trapezoidal and triangular membership functions work so well: Towards a theoretical explanation","volume":"8","author":"Barua","year":"2014","journal-title":"J. Uncertain Syst."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"980","DOI":"10.1016\/j.jfranklin.2009.03.006","article-title":"Generic two-degree-of-freedom linear and fuzzy controllers for integral processes","volume":"346","author":"Precup","year":"2009","journal-title":"J. Frankl. Inst."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"712","DOI":"10.1016\/j.ins.2009.11.018","article-title":"Multi-adjoint t-concept lattices","volume":"180","author":"Medina","year":"2010","journal-title":"Inf. Sci."},{"key":"ref_53","first-page":"1","article-title":"Medical image retrieval using vector quantization and fuzzy S-tree","volume":"41","year":"2017","journal-title":"J. Med. Syst."},{"key":"ref_54","first-page":"40","article-title":"A hybrid clustering method based on improved artificial bee colony and fuzzy C-Means algorithm","volume":"15","author":"Kumar","year":"2017","journal-title":"Int. J. Artif. Intell."},{"key":"ref_55","doi-asserted-by":"crossref","unstructured":"Wei, Y., Qiu, J., and Lam, H.-K. (2016). A novel approach to reliable output feedback control of fuzzy-affine systems with time-delays and sensor faults. IEEE Trans. Fuzzy Syst.","DOI":"10.1109\/TFUZZ.2016.2633323"},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"170","DOI":"10.1109\/TCSI.2016.2605685","article-title":"Reliable output feedback control of discrete-time fuzzy affine systems with actuator faults","volume":"64","author":"Wei","year":"2017","journal-title":"IEEE Trans. Circuits Syst. I"},{"key":"ref_57","doi-asserted-by":"crossref","unstructured":"Qiu, J., Wei, Y., Karimi, H.R., and Gao, H. (2017). Reliable control of discrete-time piecewise-affine time-delay systems via output feedback. IEEE Trans. Reliab., 1\u201313.","DOI":"10.1109\/TR.2017.2749242"},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"569","DOI":"10.1109\/TFUZZ.2016.2566810","article-title":"Approaches to T\u2013S fuzzy-affine-model-based reliable output feedback control for nonlinear it\u00f4 stochastic systems","volume":"25","author":"Wei","year":"2017","journal-title":"IEEE Trans. Fuzzy Syst."},{"key":"ref_59","unstructured":"Klir, G.J., and Yuan, B. (1995). Fuzzy Sets and Fuzzy Logic\u2014Theory and Applications, Prentice-Hall."},{"key":"ref_60","unstructured":"(2017, September 07). Defuzzification Methods. Available online: https:\/\/kr.mathworks.com\/help\/fuzzy\/examples\/defuzzification-methods.html."},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1016\/S0165-0114(97)00337-0","article-title":"Defuzzification: Criteria and classification","volume":"108","author":"Leekwijck","year":"1999","journal-title":"Fuzzy Sets Syst."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"904","DOI":"10.1016\/j.fss.2005.11.005","article-title":"Fast and accurate center of gravity defuzzification of fuzzy system outputs defined on trapezoidal fuzzy partitions","volume":"157","author":"Broekhoven","year":"2006","journal-title":"Fuzzy Sets Syst."},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"13439","DOI":"10.3390\/s131013439","article-title":"Remote gaze tracking system on a large display","volume":"13","author":"Lee","year":"2013","journal-title":"Sensors"},{"key":"ref_64","unstructured":"(2017, September 07). Renault Samsung SM5. Available online: https:\/\/en.wikipedia.org\/wiki\/Renault_Samsung_SM5."},{"key":"ref_65","unstructured":"(2017, September 11). Visual Studio 2013. Available online: https:\/\/www.visualstudio.com\/en-us\/vs."},{"key":"ref_66","unstructured":"(2017, September 11). OpenCV. Available online: http:\/\/opencv.org."},{"key":"ref_67","unstructured":"(2017, September 11). Boost C++ Library. Available online: http:\/\/www.boost.org."},{"key":"ref_68","unstructured":"Choi, I.-H., Hong, S.K., and Kim, Y.-G. (2016, January 18\u201320). Real-time categorization of driver\u2019s gaze zone using the deep learning techniques. Proceedings of the International Conference on Big Data and Smart Computing, Hong Kong, China."},{"key":"ref_69","unstructured":"Krizhevsky, A., Sutskever, I., and Hinton, G.E. (2012). Imagenet classification with deep convolutional neural networks. Advances in Neural Information Processing Systems 25, Curran Associates, Inc."}],"container-title":["Symmetry"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-8994\/9\/11\/267\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T18:48:22Z","timestamp":1760208502000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-8994\/9\/11\/267"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,11,6]]},"references-count":69,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2017,11]]}},"alternative-id":["sym9110267"],"URL":"https:\/\/doi.org\/10.3390\/sym9110267","relation":{},"ISSN":["2073-8994"],"issn-type":[{"type":"electronic","value":"2073-8994"}],"subject":[],"published":{"date-parts":[[2017,11,6]]}}}