{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,27]],"date-time":"2026-03-27T17:45:08Z","timestamp":1774633508670,"version":"3.50.1"},"reference-count":15,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2019,1,31]],"date-time":"2019-01-31T00:00:00Z","timestamp":1548892800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Inertial measurement units are commonly used to estimate the orientation of sections of sections of human body in inertial navigation systems. Most of the algorithms used for orientation estimation are computationally expensive and it is difficult to implement them in real-time embedded systems with restricted capabilities. This paper discusses a computationally inexpensive orientation estimation algorithm (Gyro Integration-Based Orientation Filter\u2014GIOF) that is used to estimate the forward and backward swing angle of the thigh (thigh angle) for a vision impaired navigation aid. The algorithm fuses the accelerometer and gyroscope readings to derive the single dimension orientation in such a way that the orientation is corrected using the accelerometer reading when it reads gravity only or otherwise integrate the gyro reading to estimate the orientation. This strategy was used to reduce the drift caused by the gyro integration. The thigh angle estimated by GIOF was compared against the Vicon Optical Motion Capture System and reported a mean correlation of 99.58% for 374 walking trials with a standard deviation of 0.34%. The Root Mean Square Error (RMSE) of the thigh angle estimated by GIOF compared with Vicon measurement was 1.8477\u00b0. The computation time on an 8-bit microcontroller running at 8 MHz for GIOF is about a half of that of Complementary Filter implementation. Although GIOF was only implemented and tested for estimating pitch of the IMU, it can be easily extended into 2D to estimate both pitch and roll.<\/jats:p>","DOI":"10.3390\/s19030596","type":"journal-article","created":{"date-parts":[[2019,2,1]],"date-time":"2019-02-01T03:08:05Z","timestamp":1548990485000},"page":"596","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":23,"title":["Validation of Thigh Angle Estimation Using Inertial Measurement Unit Data against Optical Motion Capture Systems"],"prefix":"10.3390","volume":"19","author":[{"given":"Nimsiri","family":"Abhayasinghe","sequence":"first","affiliation":[{"name":"Department of Electrical and Computer Engineering, Sri Lanka Institute of Information Technology, Malabe 10115, Sri Lanka"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Iain","family":"Murray","sequence":"additional","affiliation":[{"name":"School of Electrical Engineering, Computing and Mathematical Sciences, Curtin University of Technology, Perth 6102, Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7939-6700","authenticated-orcid":false,"given":"Shiva","family":"Sharif Bidabadi","sequence":"additional","affiliation":[{"name":"School of Civil and Mechanical Engineering, Curtin University of Technology, Perth 6102, Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,1,31]]},"reference":[{"key":"ref_1","unstructured":"Bocksch, M., Seitz, J., and Jahn, J. (2013, January 28\u201331). Pedestrian Activity Classification to Improve Human Tracking and Localization. Proceedings of the Forth International Conference on Indoor Positioning and Indoor Navigation IPIN2013, Montb\u00e9liard-Belfort, France. Available online: http:\/\/ipin2013.sciencesconf.org\/conference\/ipin2013\/eda_en.pdf."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Olsson, F., Rantakokko, J., and Nygards, J. (2014, January 27\u201330). Cooperative Localization by Foot-Mounted Inertial Navigation Systems and Ultrawideband Ranging. Proceedings of the Fifth International Conference on Indoor Positioning and Indoor Navigation (IPIN2014), Busan, Korea. Available online: http:\/\/www.ipin2014.org\/wp\/pdf\/2A-4.pdf.","DOI":"10.1109\/IPIN.2014.7275476"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1787","DOI":"10.1109\/TIE.2009.2032431","article-title":"A Kalman\/Particle Filter-Based Position and Orientation Estimation Method Using a Position Sensor\/Inertial Measurement Unit Hybrid System","volume":"57","author":"Won","year":"2010","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"273","DOI":"10.1007\/BF02345966","article-title":"Measuring orientation of human body segments using miniature gyroscopes and accelerometers","volume":"43","author":"Luinge","year":"2005","journal-title":"Med. Biol. Eng. Comput."},{"key":"ref_5","unstructured":"YEI Technology (2014, July 17). \u201cYEI 3-Space Sensor\u201d. Available online: http:\/\/www.yeitechnology.com\/yei-3-space-sensor."},{"key":"ref_6","unstructured":"(2015, July 30). Vicon. Available online: http:\/\/www.vicon.com\/."},{"key":"ref_7","unstructured":"Abhayasinghe, K., and Murray, I. (2012, January 13\u201315). A Novel Approach for Indoor Localization Using Human Gait Analysis with Gyroscopic Data. Proceedings of the Third International Conference on Indoor Positioning and Indoor Navigation (IPIN2012), Sydney, Australia. Available online: http:\/\/www.surveying.unsw.edu.au\/ipin2012\/proceedings\/submissions\/22_Paper.pdf."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Jayalath, S., and Abhayasinghe, N. (2013, January 26\u201328). A Gyroscopic Data Based Pedometer Algorithm. Proceedings of the 8th International Conference on Computer Science & Education, Colombo, Sri Lanka.","DOI":"10.1109\/ICCSE.2013.6553971"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Kwon, Y., Kang, K., Bae, C., and Cha, R.J. (2014, January 24\u201327). Cross-platform and cross-device pedometer system designed for healthcare services. In Proceeding of the 8th International Conference on Systems Biology (ISB), Qingdao, China.","DOI":"10.1109\/ISB.2014.6990738"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Abhayasinghe, N., and Murray, I. (2014, January 27\u201330). The Application of \u201coff-the-shelf\u201d Components for Building IMUs for Navigation Research. In Proceeding of the Fifth International Conference on Indoor Positioning and Indoor Navigation (IPIN2014), Busan, Korea. Available online: http:\/\/www.ipin2014.org\/wp\/pdf\/2A-3.pdf.","DOI":"10.1109\/IPIN.2014.7275475"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2776","DOI":"10.1016\/j.jbiomech.2008.06.024","article-title":"Systematic accuracy and precision analysis of video motion capturing systems\u2014exemplified on the Vicon-460 system","volume":"41","author":"Windolf","year":"2008","journal-title":"J. Biomech."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Abhayasinghe, N., and Murray, I. (2014, January 21\u201324). Human Gait Phase Recognition Based on Thigh Movement Computed using IMUs. Proceedings of the 2014 IEEE Ninth International Conference on Intelligent Sensors, Sensor Networks and Information Processing (ISSNIP), Singapore.","DOI":"10.1109\/ISSNIP.2014.6827604"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Diaz, E.M., Gonzalez, A.L.M., and M\u00fcller, F.D. (2014, January 5\u20138). Standalone inertial pocket navigation system. Proceedings of the Position, Location and Navigation Symposium - PLANS 2014, Monterey, CA, USA.","DOI":"10.1109\/PLANS.2014.6851382"},{"key":"ref_14","unstructured":"Olliw (2018, December 01). \u201cIMU Data Fusing: Complementary, Kalman, and Mahony Filter\u201d. Available online: http:\/\/www.olliw.eu\/2013\/imu-data-fusing\/."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"113","DOI":"10.1109\/7333.928571","article-title":"A reliable gait phase detection system","volume":"9","author":"Pappas","year":"2001","journal-title":"IEEE Trans. Neural Syst. Rehabil. Eng."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/3\/596\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T12:29:53Z","timestamp":1760185793000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/3\/596"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,1,31]]},"references-count":15,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2019,2]]}},"alternative-id":["s19030596"],"URL":"https:\/\/doi.org\/10.3390\/s19030596","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,1,31]]}}}