{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,21]],"date-time":"2025-10-21T15:15:31Z","timestamp":1761059731420,"version":"build-2065373602"},"reference-count":41,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2014,5,12]],"date-time":"2014-05-12T00:00:00Z","timestamp":1399852800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This paper investigates the possibility of accurately detecting and tracking human gaze by using an unconstrained and noninvasive approach based on the head pose information extracted by an RGB-D device. The main advantages of the proposed solution are that it can operate in a totally unconstrained environment, it does not require any initial calibration and it can work in real-time. These features make it suitable for being used to assist human in everyday life (e.g., remote device control) or in specific actions (e.g., rehabilitation), and in general in all those applications where it is not possible to ask for user cooperation (e.g., when users with neurological impairments are involved). To evaluate gaze estimation accuracy, the proposed approach has been largely tested and results are then compared with the leading methods in the state of the art, which, in general, make use of strong constraints on the people movements, invasive\/additional hardware and supervised pattern recognition modules. Experimental tests demonstrated that, in most cases, the errors in gaze estimation are comparable to the state of the art methods, although it works without additional constraints, calibration and supervised learning.<\/jats:p>","DOI":"10.3390\/s140508363","type":"journal-article","created":{"date-parts":[[2014,5,12]],"date-time":"2014-05-12T11:42:27Z","timestamp":1399894947000},"page":"8363-8379","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":35,"title":["An Investigation on the Feasibility of Uncalibrated and Unconstrained Gaze Tracking for Human Assistive Applications by Using Head Pose Estimation"],"prefix":"10.3390","volume":"14","author":[{"given":"Dario","family":"Cazzato","sequence":"first","affiliation":[{"name":"Faculty of Engineering, University of Salento, Lecce 73100, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marco","family":"Leo","sequence":"additional","affiliation":[{"name":"National Research Council of Italy\u2014Institute of Optics, Arnesano (LE) 73010, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Cosimo","family":"Distante","sequence":"additional","affiliation":[{"name":"National Research Council of Italy\u2014Institute of Optics, Arnesano (LE) 73010, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2014,5,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Jellinger, K. (2006). Cognitive Processes in Eye Guidance. Eur. J Neurol., 13.","DOI":"10.1111\/j.1468-1331.2006.01356.x"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Mateo, J.C., San Agustin, J., and Hansen, J.P. (2008, January 5\u201310). Gaze beats mouse: Hands-free selection by combining gaze and emg. Florence, Italy.","DOI":"10.1145\/1358628.1358804"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Doshi, A., and Trivedi, M.M. (2010, January 13\u201318). Attention estimation by simultaneous observation of viewer and view. San Francisco, CA, USA.","DOI":"10.1109\/CVPRW.2010.5543272"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Wetzel, P.A., Krueger-Anderson, G., Poprik, C., and Bascom, P. (1997). An Eye Tracking System for Analysis of Pilots' Scan Paths, Human Resources Directorate, Aircrew Training Research Division, U.S. Air Force, Armstrong Laboratory.","DOI":"10.1037\/e426332004-001"},{"key":"ref_5","unstructured":"Waizenegger, W., Atzpadin, N., Schreer, O., Feldmann, I., and Eisert, P. (October, January 30). Model based 3D gaze estimation for provision of virtual eye contact. Orlando, FL, USA."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1108\/S1548-6435(2008)0000004009","article-title":"A review of eye-tracking research in marketing","volume":"4","author":"Pieters","year":"2008","journal-title":"Rev Market. Res."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Hansen, D., and Ji, Q. (2012). In the eye of the beholder: A survey of models for eyes and gaze. IEEE Pattern Anal. Mach. Intell., doi: 10.1109\/TPAMI.2009.30.","DOI":"10.1109\/TPAMI.2009.30"},{"key":"ref_8","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_9","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_10","unstructured":"Nakazawa, A., and Nitschke, C. (2012). Computer Vision\u2013ECCV 2012, Springer."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1123","DOI":"10.1109\/TSMCB.2008.926606","article-title":"A novel gaze estimation system with one calibration point","volume":"38","author":"Villanueva","year":"2008","journal-title":"IEEE Trans. Syst. Man Cybern. Part B Cybern."},{"key":"ref_12","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_13","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_14","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_15","doi-asserted-by":"crossref","unstructured":"Funes Mora, K., and Odobez, J.M. (2012, January 16\u201321). Gaze estimation from multimodal Kinect data. Providence, RI, USA.","DOI":"10.1109\/CVPRW.2012.6239182"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Chen, J., and Ji, Q. (2008, January 8\u201311). 3D gaze estimation with a single camera without IR illumination. Tampa, FL, USA.","DOI":"10.1109\/ICPR.2008.4761343"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Kohlbecher, S., Bardinst, S., Bartl, K., Schneider, E., Poitschke, T., and Ablassmeier, M. (2008, January 26\u201328). Calibration-free eye tracking by reconstruction of the pupil ellipse in 3D space. Savannah, GA, USA.","DOI":"10.1145\/1344471.1344506"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/1687-6180-2011-40","article-title":"A 2D eye gaze estimation system with low-resolution webcam images","volume":"2011","author":"Ince","year":"2011","journal-title":"EURASIP J. Adv. Signal Process."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Janko, Z., and Hajder, L. (2012, January 2\u20135). Improving Human-Computer Interaction by gaze tracking. Kosice, Slovakia.","DOI":"10.1109\/CogInfoCom.2012.6421972"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"802","DOI":"10.1109\/TIP.2011.2162740","article-title":"Combining head pose and eye location information for gaze estimation","volume":"21","author":"Valenti","year":"2012","journal-title":"IEEE Trans. Image Process."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Stiefelhagen, R., and Zhu, J. (2002, January 20\u201325). Head orientation and gaze direction in meetings. Minneapolis, MN, USA.","DOI":"10.1145\/506443.506634"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"752","DOI":"10.3758\/BF03194970","article-title":"The influence of head contour and nose angle on the perception of eye-gaze direction","volume":"66","author":"Langton","year":"2004","journal-title":"Percept. Psychophys."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Brolly, X.L., Stratelos, C., and Mulligan, J.B. (2003, January 14\u201317). Model-based head pose estimation for air-traffic controllers. Barcelona, Spain. doi:10.1109\/ICIP.2003.1246629.","DOI":"10.1109\/ICIP.2003.1246629"},{"key":"ref_24","unstructured":"Robertson, N., Reid, I., and Brady, J. (2005, January 9). What are you looking at? gaze estimation in medium-scale images. Oxford, UK."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"16","DOI":"10.1109\/TSMCB.2008.927274","article-title":"Recognizing visual focus of attention from head pose in natural meetings","volume":"39","author":"Ba","year":"2009","journal-title":"IEEE Trans. Syst. Man Cybern. Part B Cybern."},{"key":"ref_26","first-page":"103","article-title":"A Method of Gaze Direction Estimation Considering Head Posture","volume":"6","author":"Zhang","year":"2013","journal-title":"Int. J. Signal Process. Image Process Pattern Recognit."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Benfold, B., and Reid, I. (2011, January 6\u201313). Unsupervised learning of a scene-specific coarse gaze estimator. Barcelona, Spain.","DOI":"10.1109\/ICCV.2011.6126516"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Nabati, M., and Behrad, A. (2010, January 4\u20136). Robust facial 2D motion model estimation for 3D head pose extraction and automatic camera mouse implementation. Tehran, Iran.","DOI":"10.1109\/ISTEL.2010.5734135"},{"key":"ref_29","first-page":"1","article-title":"Visual Focus of Attention in Non-calibrated Environments using Gaze Estimation","volume":"107","author":"Asteriadis","year":"2013","journal-title":"Int. J. Comput. Vis."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1109\/TCSVT.2003.818351","article-title":"Robust multipose face detection in images","volume":"14","author":"Xiao","year":"2004","journal-title":"IEEE Trans. Circuits Syst. Video Technol."},{"key":"ref_31","unstructured":"Viola, P., and Jones, M. (2001, January 8\u201314). Rapid object detection using a boosted cascade of simple features. Kauai, HI, USA."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"681","DOI":"10.1109\/34.927467","article-title":"Active appearance models","volume":"23","author":"Cootes","year":"2001","journal-title":"IEEE Trans. Pattern Anal. Mach. Intell."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Zhou, M., Liang, L., Sun, J., and Wang, Y. (2010, January 13\u201318). AAM based face tracking with temporal matching and face segmentation. San Francisco, CA, USA.","DOI":"10.1109\/CVPR.2010.5540146"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1109\/34.121791","article-title":"A method for registration of 3-D shapes","volume":"14","author":"Besl","year":"1992","journal-title":"IEEE Trans. Pattern Anal. Mach. Intell."},{"key":"ref_35","unstructured":"Ahlberg, J. (2001). Candide-3-an Updated Parameterised Face, Department of Electrical Engineering, Linkping University. Report No. LiTH-ISY-R-2326."},{"key":"ref_36","unstructured":"Li, Z., Sastry, S.S., and Murray, R. (1994). A Mathematical Introduction to Robotic Manipulation, CRC Press."},{"key":"ref_37","unstructured":"MSDN-Microsoft. Available online: http:\/\/msdn.microsoft.com\/en-us\/library\/jj131033.aspx."},{"key":"ref_38","unstructured":"Lu, F., Okabe, T., Sugano, Y., and Sato, Y. (September, January 29). A Head Pose-free Approach for Appearance-Based Gaze Estimation. Dundee Scotland."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"169","DOI":"10.1016\/j.imavis.2014.01.005","article-title":"Learning gaze biases with head motion for head pose-free gaze estimation","volume":"32","author":"Lu","year":"2014","journal-title":"Image Vis. Comput."},{"key":"ref_40","unstructured":"Sugano, Y, Matsushita, Y., Sato, Y., and Koike, H. (2008). Computer Vision\u2013ECCV 2008, Springer: Berlin\/Heidelberg."},{"key":"ref_41","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. 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