Allen, Tom

Dunn, Marcus

Sheffield Hallam University Research Archive

Validation of a method to assess offside technologies in dynamic movementDUNN, Marcus <http://orcid.org/0000-0003-3368-8131> and ALLEN, TomAvailable from Sheffield Hallam University Research Archive (SHURA) at:http://shura.shu.ac.uk/29245/This document is the author deposited version.  You are advised to consult the publisher's version if you wish to cite from it.Published versionDUNN, Marcus and ALLEN, Tom (2021). Validation of a method to assess offside technologies in dynamic movement. In: 2021 FIFA Research Synergy Workshop, 11 Oct 2021. Federation Internationale de Football Association. (Unpublished) Copyright and re-use policySee http://shura.shu.ac.uk/information.htmlSheffield Hallam University Research Archivehttp://shura.shu.ac.ukValidation of a method to assess offside technologies in dynamic movementDr Marcus DunnResearch Fellow (Sports Engineering and Biomechanics)Sports Engineering Research Group,Sheffield Hallam University, UKBackground• Accessible, high-speed video (HSV) approach to determine:• Instant of offside event.• Position of offside event during dynamic movement.• Assessments:• Number of identifiable events.• Three-dimensional body marker accuracy.• Considerations:• Large (20 m3) player volume, camera pairings (LC, CR and LR).YXLeftCentreORightKick cameraProposed approach5 m2 m2 mResultsOffside event and LEDs illuminating clearly to identify 0.001 s time intervals• Instant of offside event:• HSV and high-refresh rate LED timing system demonstrates ability to accurately identify offside instant and corresponding broadcast image.• Body markers visible in paired images:• LC: 77%, CR: 71%, LR: 75%.• Three-dimensional position: pitch calibrationResults• Three-dimensional position: pitch calibration• Accuracy (RMSE) of player volume definition (e.g., O, X and Y locations resp.):• TotalStation: 52, 50 and 23 mm.• HSV cameras: 45, 84 and 10 mm.ResultsTotal Station vs optical motion capture to assess pitch calibrationHSV cameras vs optical motion capture to assess pitch calibrationO YXResultsMarker LC CR LRHead (mm) 53 109 44R Shoulder (mm) 45 98 29L Shoulder (mm) 53 111 39R Knee (mm) 66 100 45L Knee (mm) 68 111 45Mean (mm) 57 106 40• Three-dimensional position: body markers• Reliability (SEM) of body markers in HSV camera coordinate system:• LC: 0.23 mm, CR: 0.53 mm, LR: 0.23 mm.• Accuracy (RMSE) of body markers transformed to pitch coordinate system (each camera pair):• Body markers identified with good precision (~40 mm) for majority (75%) of offside events captured.• Offside measures transformed to goal line were problematic owing to need for accurately defined three-dimensional pitch transformation.• Transformation error sources included TotalStation surveying and HSV camera definitions of player volume.• Recommended to include goal line in capture volumes, to avoid data transformation until this aspect of approach is explored further.Interpretation• HSV cameras represent a flexible approach to assess semi-automated offside technologies (e.g., accessible, scalable, applicable to pattern clothing).• Offside measures where goal line not incorporated into capture volume problematic; however, measures incorporating other markings (e.g., 18 yd, 6 yd lines) hold merit.• Future work should explore use of patterned clothing and include other pitch markings and their orientation (e.g., wide-view of pitch), to minimise errors associated with goal line-based player measurements.Future applicationsThank youm.dunn@shu.ac.uk@MarcusDunnPhDwww.shu.ac.uk/cser

Validation of a method to assess offside technologies in dynamic movement

http://shura.shu.ac.uk/29245/1/M%20Dunn%20-%202021%20FIFA%20Research%20Synergy%20Workshop.pdf

Validation of a method to assess offside technologies in dynamic movement

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