{"id":"https://openalex.org/W4407155106","doi":"https://doi.org/10.1109/access.2025.3538917","title":"Adaptive Focal Loss for Keypoint-Based Deep Learning Detectors Addressing Class Imbalance","display_name":"Adaptive Focal Loss for Keypoint-Based Deep Learning Detectors Addressing Class Imbalance","publication_year":2025,"publication_date":"2025-01-01","ids":{"openalex":"https://openalex.org/W4407155106","doi":"https://doi.org/10.1109/access.2025.3538917"},"language":"en","primary_location":{"id":"doi:10.1109/access.2025.3538917","is_oa":true,"landing_page_url":"https://doi.org/10.1109/access.2025.3538917","pdf_url":null,"source":{"id":"https://openalex.org/S2485537415","display_name":"IEEE Access","issn_l":"2169-3536","issn":["2169-3536"],"is_oa":true,"is_in_doaj":true,"is_core":true,"host_organization":"https://openalex.org/P4310319808","host_organization_name":"Institute of Electrical and Electronics Engineers","host_organization_lineage":["https://openalex.org/P4310319808"],"host_organization_lineage_names":["Institute of Electrical and Electronics Engineers"],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"IEEE Access","raw_type":"journal-article"},"type":"article","indexed_in":["crossref","doaj"],"open_access":{"is_oa":true,"oa_status":"gold","oa_url":"https://doi.org/10.1109/access.2025.3538917","any_repository_has_fulltext":true},"authorships":[{"author_position":"first","author":{"id":"https://openalex.org/A5003161716","display_name":"Zhihao Su","orcid":"https://orcid.org/0009-0002-1238-3929"},"institutions":[{"id":"https://openalex.org/I885383172","display_name":"National University of Malaysia","ror":"https://ror.org/00bw8d226","country_code":"MY","type":"education","lineage":["https://openalex.org/I885383172"]}],"countries":["MY"],"is_corresponding":false,"raw_author_name":"Zhihao Su","raw_affiliation_strings":["Center for Artificial Intelligence Technology, Faculty of Information Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia","Faculty of Information Science and Technology, Center for Artificial Intelligence Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia"],"raw_orcid":"https://orcid.org/0009-0002-1238-3929","affiliations":[{"raw_affiliation_string":"Center for Artificial Intelligence Technology, Faculty of Information Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia","institution_ids":["https://openalex.org/I885383172"]},{"raw_affiliation_string":"Faculty of Information Science and Technology, Center for Artificial Intelligence Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia","institution_ids":["https://openalex.org/I885383172"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5012504588","display_name":"Afzan Adam","orcid":"https://orcid.org/0000-0003-1116-1005"},"institutions":[{"id":"https://openalex.org/I885383172","display_name":"National University of Malaysia","ror":"https://ror.org/00bw8d226","country_code":"MY","type":"education","lineage":["https://openalex.org/I885383172"]}],"countries":["MY"],"is_corresponding":false,"raw_author_name":"Afzan Adam","raw_affiliation_strings":["Center for Artificial Intelligence Technology, Faculty of Information Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia","Faculty of Information Science and Technology, Center for Artificial Intelligence Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia"],"raw_orcid":"https://orcid.org/0000-0003-1116-1005","affiliations":[{"raw_affiliation_string":"Center for Artificial Intelligence Technology, Faculty of Information Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia","institution_ids":["https://openalex.org/I885383172"]},{"raw_affiliation_string":"Faculty of Information Science and Technology, Center for Artificial Intelligence Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia","institution_ids":["https://openalex.org/I885383172"]}]},{"author_position":"last","author":{"id":"https://openalex.org/A5000097176","display_name":"Mohammad Faidzul Nasrudin","orcid":"https://orcid.org/0000-0002-2003-8853"},"institutions":[{"id":"https://openalex.org/I885383172","display_name":"National University of Malaysia","ror":"https://ror.org/00bw8d226","country_code":"MY","type":"education","lineage":["https://openalex.org/I885383172"]}],"countries":["MY"],"is_corresponding":false,"raw_author_name":"Mohammad Faidzul Nasrudin","raw_affiliation_strings":["Center for Artificial Intelligence Technology, Faculty of Information Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia","Faculty of Information Science and Technology, Center for Artificial Intelligence Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"Center for Artificial Intelligence Technology, Faculty of Information Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia","institution_ids":["https://openalex.org/I885383172"]},{"raw_affiliation_string":"Faculty of Information Science and Technology, Center for Artificial Intelligence Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia","institution_ids":["https://openalex.org/I885383172"]}]}],"institutions":[],"countries_distinct_count":1,"institutions_distinct_count":1,"corresponding_author_ids":[],"corresponding_institution_ids":["https://openalex.org/I885383172"],"apc_list":{"value":1850,"currency":"USD","value_usd":1850},"apc_paid":{"value":1850,"currency":"USD","value_usd":1850},"fwci":22.1721,"has_fulltext":false,"cited_by_count":17,"citation_normalized_percentile":{"value":0.99323224,"is_in_top_1_percent":true,"is_in_top_10_percent":true},"cited_by_percentile_year":{"min":99,"max":100},"biblio":{"volume":"13","issue":null,"first_page":"31842","last_page":"31856"},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T11598","display_name":"Internet Traffic Analysis and Secure E-voting","score":0.9513999819755554,"subfield":{"id":"https://openalex.org/subfields/1702","display_name":"Artificial Intelligence"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},"topics":[{"id":"https://openalex.org/T11598","display_name":"Internet Traffic Analysis and Secure E-voting","score":0.9513999819755554,"subfield":{"id":"https://openalex.org/subfields/1702","display_name":"Artificial Intelligence"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T12357","display_name":"Digital Media Forensic Detection","score":0.9480000138282776,"subfield":{"id":"https://openalex.org/subfields/1707","display_name":"Computer Vision and Pattern Recognition"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T10964","display_name":"Wireless Communication Security Techniques","score":0.9254999756813049,"subfield":{"id":"https://openalex.org/subfields/2208","display_name":"Electrical and Electronic Engineering"},"field":{"id":"https://openalex.org/fields/22","display_name":"Engineering"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}}],"keywords":[{"id":"https://openalex.org/keywords/computer-science","display_name":"Computer science","score":0.6780230402946472},{"id":"https://openalex.org/keywords/detector","display_name":"Detector","score":0.5496649146080017},{"id":"https://openalex.org/keywords/class","display_name":"Class (philosophy)","score":0.5422206521034241},{"id":"https://openalex.org/keywords/artificial-intelligence","display_name":"Artificial intelligence","score":0.5163894295692444},{"id":"https://openalex.org/keywords/deep-learning","display_name":"Deep learning","score":0.43853509426116943},{"id":"https://openalex.org/keywords/remote-sensing","display_name":"Remote sensing","score":0.35289400815963745},{"id":"https://openalex.org/keywords/computer-vision","display_name":"Computer vision","score":0.322505384683609},{"id":"https://openalex.org/keywords/telecommunications","display_name":"Telecommunications","score":0.1416066288948059},{"id":"https://openalex.org/keywords/geology","display_name":"Geology","score":0.10128653049468994}],"concepts":[{"id":"https://openalex.org/C41008148","wikidata":"https://www.wikidata.org/wiki/Q21198","display_name":"Computer science","level":0,"score":0.6780230402946472},{"id":"https://openalex.org/C94915269","wikidata":"https://www.wikidata.org/wiki/Q1834857","display_name":"Detector","level":2,"score":0.5496649146080017},{"id":"https://openalex.org/C2777212361","wikidata":"https://www.wikidata.org/wiki/Q5127848","display_name":"Class (philosophy)","level":2,"score":0.5422206521034241},{"id":"https://openalex.org/C154945302","wikidata":"https://www.wikidata.org/wiki/Q11660","display_name":"Artificial intelligence","level":1,"score":0.5163894295692444},{"id":"https://openalex.org/C108583219","wikidata":"https://www.wikidata.org/wiki/Q197536","display_name":"Deep learning","level":2,"score":0.43853509426116943},{"id":"https://openalex.org/C62649853","wikidata":"https://www.wikidata.org/wiki/Q199687","display_name":"Remote sensing","level":1,"score":0.35289400815963745},{"id":"https://openalex.org/C31972630","wikidata":"https://www.wikidata.org/wiki/Q844240","display_name":"Computer vision","level":1,"score":0.322505384683609},{"id":"https://openalex.org/C76155785","wikidata":"https://www.wikidata.org/wiki/Q418","display_name":"Telecommunications","level":1,"score":0.1416066288948059},{"id":"https://openalex.org/C127313418","wikidata":"https://www.wikidata.org/wiki/Q1069","display_name":"Geology","level":0,"score":0.10128653049468994}],"mesh":[],"locations_count":2,"locations":[{"id":"doi:10.1109/access.2025.3538917","is_oa":true,"landing_page_url":"https://doi.org/10.1109/access.2025.3538917","pdf_url":null,"source":{"id":"https://openalex.org/S2485537415","display_name":"IEEE Access","issn_l":"2169-3536","issn":["2169-3536"],"is_oa":true,"is_in_doaj":true,"is_core":true,"host_organization":"https://openalex.org/P4310319808","host_organization_name":"Institute of Electrical and Electronics Engineers","host_organization_lineage":["https://openalex.org/P4310319808"],"host_organization_lineage_names":["Institute of Electrical and Electronics Engineers"],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"IEEE Access","raw_type":"journal-article"},{"id":"pmh:oai:doaj.org/article:0850e11013cd4fb7aeb968796871b199","is_oa":true,"landing_page_url":"https://doaj.org/article/0850e11013cd4fb7aeb968796871b199","pdf_url":null,"source":{"id":"https://openalex.org/S4306401280","display_name":"DOAJ (DOAJ: Directory of Open Access Journals)","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_core":false,"host_organization":null,"host_organization_name":null,"host_organization_lineage":[],"host_organization_lineage_names":[],"type":"repository"},"license":"cc-by-sa","license_id":"https://openalex.org/licenses/cc-by-sa","version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"IEEE Access, Vol 13, Pp 31842-31856 (2025)","raw_type":"article"}],"best_oa_location":{"id":"doi:10.1109/access.2025.3538917","is_oa":true,"landing_page_url":"https://doi.org/10.1109/access.2025.3538917","pdf_url":null,"source":{"id":"https://openalex.org/S2485537415","display_name":"IEEE Access","issn_l":"2169-3536","issn":["2169-3536"],"is_oa":true,"is_in_doaj":true,"is_core":true,"host_organization":"https://openalex.org/P4310319808","host_organization_name":"Institute of Electrical and Electronics Engineers","host_organization_lineage":["https://openalex.org/P4310319808"],"host_organization_lineage_names":["Institute of Electrical and Electronics Engineers"],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"IEEE Access","raw_type":"journal-article"},"sustainable_development_goals":[],"awards":[{"id":"https://openalex.org/G7629098766","display_name":null,"funder_award_id":"FRGS/1/2022/ICT02/UKM/02/5","funder_id":"https://openalex.org/F4320321709","funder_display_name":"Ministry of Higher Education, Malaysia"}],"funders":[{"id":"https://openalex.org/F4320321709","display_name":"Ministry of Higher Education, Malaysia","ror":"https://ror.org/05mcs2t73"}],"has_content":{"grobid_xml":false,"pdf":false},"content_urls":null,"referenced_works_count":49,"referenced_works":["https://openalex.org/W1861492603","https://openalex.org/W2031489346","https://openalex.org/W2037227137","https://openalex.org/W2549139847","https://openalex.org/W2948672349","https://openalex.org/W2963113370","https://openalex.org/W2963351448","https://openalex.org/W2963691377","https://openalex.org/W2963786238","https://openalex.org/W2963927307","https://openalex.org/W2969844348","https://openalex.org/W2982769033","https://openalex.org/W2989604896","https://openalex.org/W2997604048","https://openalex.org/W3010225291","https://openalex.org/W3012573144","https://openalex.org/W3034933032","https://openalex.org/W3035524459","https://openalex.org/W3035552357","https://openalex.org/W3035729912","https://openalex.org/W3080951715","https://openalex.org/W3092663126","https://openalex.org/W3093220398","https://openalex.org/W3097255365","https://openalex.org/W3166596953","https://openalex.org/W3172971995","https://openalex.org/W3198342818","https://openalex.org/W3203170887","https://openalex.org/W4214494681","https://openalex.org/W4221153269","https://openalex.org/W4283791586","https://openalex.org/W4287891158","https://openalex.org/W4312789460","https://openalex.org/W4364321988","https://openalex.org/W4386806338","https://openalex.org/W4387092712","https://openalex.org/W4389937314","https://openalex.org/W4390670538","https://openalex.org/W4391305686","https://openalex.org/W4392122189","https://openalex.org/W4392903013","https://openalex.org/W4393284018","https://openalex.org/W6620707391","https://openalex.org/W6764733053","https://openalex.org/W6768920361","https://openalex.org/W6779586474","https://openalex.org/W6780957418","https://openalex.org/W6870939646","https://openalex.org/W6873811160"],"related_works":["https://openalex.org/W2366906938","https://openalex.org/W4375867731","https://openalex.org/W2349391998","https://openalex.org/W4205655149","https://openalex.org/W2000775715","https://openalex.org/W2074467390","https://openalex.org/W2611989081","https://openalex.org/W2795393339","https://openalex.org/W2626393719","https://openalex.org/W4390618967"],"abstract_inverted_index":{"Keypoint-based":[0],"deep":[1],"learning":[2],"detectors":[3],"have":[4,64,75],"proven":[5],"highly":[6],"effective":[7],"in":[8,45,192,202,263,271],"object":[9,18],"detection":[10,47],"tasks":[11],"by":[12,217],"predicting":[13],"specific":[14],"keypoints":[15],"to":[16,39,67,80,125,180,240,256],"determine":[17],"classification":[19],"and":[20,29,61,82,110,156,224,231,253],"location.":[21],"Examples":[22],"include":[23],"CornerNet,":[24],"CenterNet,":[25],"ExtremeNet,":[26],"RetinaNet,":[27],"FCOS,":[28],"ObjectBox.":[30],"Despite":[31],"their":[32],"strengths,":[33],"these":[34,72,93],"methods":[35,63,147],"are":[36],"particularly":[37],"susceptible":[38],"class":[40,195,257],"imbalance,":[41,258],"which":[42,102],"can":[43],"result":[44],"poor":[46],"performance":[48,262],"for":[49],"less":[50],"frequent":[51],"classes.":[52],"Popular":[53],"solutions":[54],"such":[55],"as":[56],"hard":[57],"sampling,":[58,60],"soft":[59],"sampling-free":[62],"been":[65],"proposed":[66],"tackle":[68],"this":[69,95],"issue.":[70],"However,":[71],"approaches":[73],"often":[74],"inherent":[76],"limitations,":[77],"including":[78],"sensitivity":[79],"hyperparameters":[81],"neglecting":[83],"the":[84,88,104,127,133,152,162,181,203,213,227,242],"gradient":[85],"dynamics":[86],"of":[87,106,129,136,170,220,245],"loss":[89],"function.":[90],"To":[91],"address":[92],"challenges,":[94],"paper":[96],"proposes":[97],"Adaptive":[98,117],"Focal":[99,107,183,215],"Loss":[100,108,112,184,216],"(AFL),":[101],"combines":[103],"strengths":[105],"(FL)":[109],"Class-Balanced":[111],"(CBL)":[113],"while":[114],"introducing":[115],"an":[116,167,218],"Gradient":[118],"Function.":[119],"This":[120,236],"function":[121],"is":[122],"specifically":[123],"designed":[124],"mitigate":[126],"impact":[128],"large":[130],"gradients":[131],"during":[132],"early":[134],"stages":[135],"training.":[137],"Extensive":[138],"experiments":[139],"demonstrate":[140],"that":[141],"AFL":[142,165,198,259],"significantly":[143],"outperforms":[144],"classical":[145],"sampling":[146],"across":[148,185],"key":[149],"metrics":[150],"on":[151,161,226],"MS":[153,229],"COCO,":[154,230],"LVIS,":[155,228],"PASCAL":[157,232],"VOC":[158,233],"datasets.":[159],"Notably,":[160],"LVIS":[163],"dataset,":[164],"achieves":[166],"average":[168,219],"improvement":[169],"over":[171,221],"3%":[172],"<inline-formula":[173,204],"xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"":[174,205],"xmlns:xlink=\"http://www.w3.org/1999/xlink\">":[175,206],"<tex-math":[176,207],"notation=\"LaTeX\">$AP_{r}$":[177],"</tex-math></inline-formula>":[178,210],"compared":[179],"baseline":[182,214],"multiple":[186],"keypoint-based":[187,272],"detectors,":[188],"showcasing":[189],"its":[190],"effectiveness":[191],"enhancing":[193],"rare":[194],"accuracy.":[196],"Furthermore,":[197],"delivers":[199],"substantial":[200],"improvements":[201],"notation=\"LaTeX\">$AP_{0.5\\sim":[208],"0.95}$":[209],"metric,":[211],"surpassing":[212],"2%,":[222],"1%,":[223],"0.2%":[225],"datasets,":[234],"respectively.":[235],"highlights":[237],"AFL\u2019s":[238],"capability":[239],"enhance":[241],"overall":[243],"accuracy":[244],"foreground":[246],"objects.":[247],"By":[248],"providing":[249],"a":[250,268],"more":[251],"balanced":[252],"robust":[254],"solution":[255],"demonstrates":[260],"superior":[261],"challenging":[264],"scenarios,":[265],"making":[266],"it":[267],"valuable":[269],"advancement":[270],"detection.":[273]},"counts_by_year":[{"year":2026,"cited_by_count":7},{"year":2025,"cited_by_count":10}],"updated_date":"2026-07-15T18:14:33.161393","created_date":"2025-10-10T00:00:00"}