[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-detail-227384-en":3,"doc-seo-227384-105":29,"detail-sidebar-cat-0-en-105":89},{"code":4,"msg":5,"data":6},0,"success",{"doc_id":7,"user_id":8,"nickname":9,"user_avatar":10,"doc_module":4,"category_id":11,"category_name":12,"doc_title":13,"doc_description":14,"doc_content":15,"file_id":16,"file_url":17,"file_type":18,"file_size":19,"view_count":4,"is_deleted":4,"is_public":20,"is_downloadable":20,"audit_status":20,"page_count":20,"language":21,"language_code":22,"site_id":23,"html_lang":22,"table_of_contents":24,"faqs":25,"seo_title":26,"seo_description":14,"update_tm":27,"read_time":28},227384,3573418547284,"Graffin","https://eur-avatar.wpscdn.com/davatar_994ba38a5ba835b3df7d355c54d3ed8d",8,"Research & Report","Person Identification from Biological Motion - Viewpoint Dependencies","Study investigates how learning viewpoint affects recognition of animate agents in biological motion. Observers learned to identify seven unfamiliar male walkers shown as point-light displays from one of three perspectives: frontal, half-profile, or profile. In later tests, identification was required from all viewing angles to assess viewpoint generalization. Results show strong effects of harmonics composition and a highly significant interaction between training and test viewpoint, with best performance when viewpoints match.","Person Identification from Biological Motion: Viewpoint Dependencies  \nCord Westhoff, Nikolaus F. Troje  \n[cord.westhoff @ruhr-uni-bochum.de](cord.westhoff @ruhr-uni-bochum.de) [troje@psyc.queensu.ca](troje@psyc.queensu.ca)[ ](troje@psyc.queensu.ca)[www.bml.psy.ruhr-uni-bochum.de](www.bml.psy.ruhr-uni-bochum.de)  \nIntroduction  \nRegarding complex 3D-objects, observers show a decreasing recognition performance with an increasing difference between the learning viewpoint and the test view, but little is known about viewpoint generalization of animate objects. We investigated this problem using biological motion. Observers learned to identify seven unknown male walkers, which were shown as point-light displays, from one of three possible viewpoints: frontal, half-profile, or profile view. In a following session, the same walkers had to be identified from all three viewing angles Therefore, the first question of this study can be formulated as:  \nIs there a viewpoint effect between learning view and test view in the identification of point-light walkers ?  \nA walking pattern can be described very accurately using Fourier analysis. This results in an average posture and the first few harmonics, resembling the dynamic components of the walk (Troje, 2002) . In the database used in this study, the first harmonic covers on average about 91% of the overall variance of an individual`s walk, the second harmonic another 6% . Therefore, one might hypothesize that only the first harmonic is relevant for person identification. Thus, our second goal was to find an answer to the question:  \nScores of the first four principal components over walk cycles (x-axis) From: Troje (2002)  \n91.2  \n6.4  \n1.4 0.6 0.4 Harmonic  \nAmount of variance in a gait pattern explained by the harmonics  \nVariance (%)  \nIs there a proportional relation between the amount of variance a harmonic explains and its importance for person identification?  \nMethods  \nParticipants:  \n18 Observers (9 females, 9 males), subdivided into three groups of equal size, according to the viewing angle of the displays.  \nStimuli:  \nTraining stimuli were Fourier-represented point-light walkers decomposed into an average posture and the first five harmonics, previously normalized with respect to their shape and gait frequency. For each subject, seven walkers were chosen randomly from a database and shown from either a frontal view (FV), half-profile view (HV°) or profile view (PV) . For the creation of the test stimuli we first computed an average walker and then replaced either only its first (H1), second (H2), or third to fifth harmonics (H3-5) with the respective harmonics of the individual  \nFV HV PV  \n(Lines not present in actual displays)  \nDay 1  \n4 Training Sessions Test Session A  \n(Constant viewpoint)  \nDay 2  \n2 Training Sessions Test Session B  \n(Varying viewpoints)  \nDesign and procedure:  \nDisplays were shown for 3s, and subjects answered by clicking on one of seven buttons with the names of the walkers. On the first day, four training sessions (140 reinforced trials each) were conducted with the original walker representations, followed by a nonreinforced test session A. Viewing angle remained constant throughout these sessions. On the second day observers were re-trained in two more training sessions. In the final test session B (168 trials) we additionally varied the viewing angle of the displays to examine the generalization performance from the learning view to the other two viewing angles.  \nResults  \nTraining sessions  \n\n| Learning curve\u003Cbr>\u003Cbr>1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58\u003Cbr>Block |  |\n| --- | --- |\n|  | \u003Cbr>All groups Frontal iw Half-View Profile V iew |\n|  |  |\n\nThe vertical line indicates the end of the first training day and the conduction of Test session A  \n7 Groups quickly improved their performances  \n7 Significant improvement between the end of the first and the second day in the Frontal-and the Profile-view groups  \n7 No overall d","cbCaifl7hTg3kPUt","https://ap.wps.com/l/cbCaifl7hTg3kPUt","pdf",348319,1,"English","en",105,"# Introduction\n# Methods\n## Participants\n## Stimuli\n## Design and procedure\n# Results\n## Training sessions\n## Test session A\n## Test session B\n# Discussion","[{\"question\":\"What is the main question about viewpoint effects in this study?\",\"answer\":\"The study asks whether recognition performance depends on the viewpoint used during learning versus the viewpoint used during testing for point-light walker identification.\"},{\"question\":\"How were the training and test stimuli constructed?\",\"answer\":\"Walkers were represented as Fourier-decomposed point-light displays, using an average posture plus selected harmonics. Test stimuli replaced specific harmonic ranges to create conditions such as H1, H2, or H3-5.\"},{\"question\":\"What determines recognition performance most strongly in the results?\",\"answer\":\"Recognition accuracy shows a clear main effect of harmonics, and test session B additionally reveals a strong interaction between training viewpoint and test viewpoint, with best performance when they match.\"}]","Person Identification from Biological Motion - Viewpoint Dependencies | PDF",1789007677,3,{"code":4,"msg":30,"data":31},"ok",{"site_id":23,"language":22,"slug":32,"title":13,"keywords":33,"description":14,"schema_data":34,"social_meta":84,"head_meta":86,"extra_data":88,"updated_unix":27},"person-identification-from-biological-motion-viewpoint-dependencies","",{"@graph":35,"@context":83},[36,52,66],{"@type":37,"itemListElement":38},"BreadcrumbList",[39,43,47,49],{"item":40,"name":41,"@type":42,"position":20},"https://docshare.wps.com","Home","ListItem",{"item":44,"name":45,"@type":42,"position":46},"https://docshare.wps.com/document/","Document",2,{"item":48,"name":12,"@type":42,"position":28},"https://docshare.wps.com/document/research-report/",{"item":50,"name":13,"@type":42,"position":51},"https://docshare.wps.com/document/person-identification-from-biological-motion-viewpoint-dependencies/227384/",4,{"url":50,"name":13,"@type":53,"author":54,"headline":13,"publisher":56,"fileFormat":59,"inLanguage":22,"description":14,"dateModified":60,"datePublished":60,"encodingFormat":59,"isAccessibleForFree":61,"interactionStatistic":62},"DigitalDocument",{"name":9,"@type":55},"Person",{"url":40,"name":57,"@type":58},"DocShare","Organization","application/pdf","2026-09-10",true,{"@type":63,"interactionType":64,"userInteractionCount":4},"InteractionCounter",{"@type":65},"ViewAction",{"@type":67,"mainEntity":68},"FAQPage",[69,75,79],{"name":70,"@type":71,"acceptedAnswer":72},"What is the main question about viewpoint effects in this study?","Question",{"text":73,"@type":74},"The study asks whether recognition performance depends on the viewpoint used during learning versus the viewpoint used during testing for point-light walker identification.","Answer",{"name":76,"@type":71,"acceptedAnswer":77},"How were the training and test stimuli constructed?",{"text":78,"@type":74},"Walkers were represented as Fourier-decomposed point-light displays, using an average posture plus selected harmonics. Test stimuli replaced specific harmonic ranges to create conditions such as H1, H2, or H3-5.",{"name":80,"@type":71,"acceptedAnswer":81},"What determines recognition performance most strongly in the results?",{"text":82,"@type":74},"Recognition accuracy shows a clear main effect of harmonics, and test session B additionally reveals a strong interaction between training viewpoint and test viewpoint, with best performance when they match.","https://schema.org",{"og:url":50,"og:type":85,"og:title":13,"og:site_name":57,"og:description":14},"article",{"robots":87,"canonical":50},"index,follow",{"doc_id":7,"site_id":23},{"code":4,"msg":5,"data":90},[91,95,99,103,108,113,118,121,126,129,133],{"id":20,"doc_module":4,"doc_module_name":45,"category_name":92,"show_sort_weight":93,"slug":94},"Story & Novel",90,"story-novel",{"id":46,"doc_module":4,"doc_module_name":45,"category_name":96,"show_sort_weight":97,"slug":98},"Literature",80,"literature",{"id":51,"doc_module":4,"doc_module_name":45,"category_name":100,"show_sort_weight":101,"slug":102},"Exam",70,"exam",{"id":104,"doc_module":4,"doc_module_name":45,"category_name":105,"show_sort_weight":106,"slug":107},5,"Comic",60,"comic",{"id":109,"doc_module":4,"doc_module_name":45,"category_name":110,"show_sort_weight":111,"slug":112},6,"Technology",50,"technology",{"id":114,"doc_module":4,"doc_module_name":45,"category_name":115,"show_sort_weight":116,"slug":117},7,"Healthcare",40,"healthcare",{"id":11,"doc_module":4,"doc_module_name":45,"category_name":12,"show_sort_weight":119,"slug":120},30,"research-report",{"id":122,"doc_module":4,"doc_module_name":45,"category_name":123,"show_sort_weight":124,"slug":125},9,"Religion & Spirituality",20,"religion-spirituality",{"id":124,"doc_module":4,"doc_module_name":45,"category_name":127,"show_sort_weight":124,"slug":128},"World Cup","world-cup",{"id":130,"doc_module":4,"doc_module_name":45,"category_name":131,"show_sort_weight":130,"slug":132},10,"Lifestyle","lifestyle",{"id":134,"doc_module":4,"doc_module_name":45,"category_name":135,"show_sort_weight":104,"slug":136},19,"General","general"]