{"id":"https://openalex.org/W3206966913","doi":"https://doi.org/10.3390/rs13193902","title":"Estimation of Apple Tree Leaf Chlorophyll Content Based on Machine Learning Methods","display_name":"Estimation of Apple Tree Leaf Chlorophyll Content Based on Machine Learning Methods","publication_year":2021,"publication_date":"2021-09-29","ids":{"openalex":"https://openalex.org/W3206966913","doi":"https://doi.org/10.3390/rs13193902","mag":"3206966913"},"language":"en","primary_location":{"id":"doi:10.3390/rs13193902","is_oa":true,"landing_page_url":"https://doi.org/10.3390/rs13193902","pdf_url":"https://www.mdpi.com/2072-4292/13/19/3902/pdf?version=1633673236","source":{"id":"https://openalex.org/S43295729","display_name":"Remote Sensing","issn_l":"2072-4292","issn":["2072-4292"],"is_oa":true,"is_in_doaj":true,"is_core":true,"host_organization":"https://openalex.org/P4310310987","host_organization_name":"Multidisciplinary Digital Publishing Institute","host_organization_lineage":["https://openalex.org/P4310310987"],"host_organization_lineage_names":["Multidisciplinary Digital Publishing Institute"],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Remote Sensing","raw_type":"journal-article"},"type":"article","indexed_in":["crossref","doaj"],"open_access":{"is_oa":true,"oa_status":"gold","oa_url":"https://www.mdpi.com/2072-4292/13/19/3902/pdf?version=1633673236","any_repository_has_fulltext":true},"authorships":[{"author_position":"first","author":{"id":"https://openalex.org/A5066731170","display_name":"Na Ta","orcid":"https://orcid.org/0000-0002-7996-259X"},"institutions":[{"id":"https://openalex.org/I89652312","display_name":"Northwest A&F University","ror":"https://ror.org/0051rme32","country_code":"CN","type":"education","lineage":["https://openalex.org/I89652312"]}],"countries":["CN"],"is_corresponding":false,"raw_author_name":"Na Ta","raw_affiliation_strings":["College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China"],"affiliations":[{"raw_affiliation_string":"College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China","institution_ids":["https://openalex.org/I89652312"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5103221662","display_name":"Qingrui Chang","orcid":"https://orcid.org/0000-0001-7154-6068"},"institutions":[{"id":"https://openalex.org/I89652312","display_name":"Northwest A&F University","ror":"https://ror.org/0051rme32","country_code":"CN","type":"education","lineage":["https://openalex.org/I89652312"]}],"countries":["CN"],"is_corresponding":true,"raw_author_name":"Qingrui Chang","raw_affiliation_strings":["College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China"],"affiliations":[{"raw_affiliation_string":"College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China","institution_ids":["https://openalex.org/I89652312"]}]},{"author_position":"last","author":{"id":"https://openalex.org/A5015929537","display_name":"Youming Zhang","orcid":"https://orcid.org/0000-0003-3361-1708"},"institutions":[{"id":"https://openalex.org/I89652312","display_name":"Northwest A&F University","ror":"https://ror.org/0051rme32","country_code":"CN","type":"education","lineage":["https://openalex.org/I89652312"]}],"countries":["CN"],"is_corresponding":false,"raw_author_name":"Youming Zhang","raw_affiliation_strings":["College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China"],"affiliations":[{"raw_affiliation_string":"College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China","institution_ids":["https://openalex.org/I89652312"]}]}],"institutions":[],"countries_distinct_count":1,"institutions_distinct_count":3,"corresponding_author_ids":["https://openalex.org/A5103221662"],"corresponding_institution_ids":["https://openalex.org/I89652312"],"apc_list":{"value":2500,"currency":"CHF","value_usd":2707},"apc_paid":{"value":2500,"currency":"CHF","value_usd":2707},"fwci":9.0714,"has_fulltext":true,"cited_by_count":52,"citation_normalized_percentile":{"value":0.97805797,"is_in_top_1_percent":false,"is_in_top_10_percent":true},"cited_by_percentile_year":{"min":99,"max":100},"biblio":{"volume":"13","issue":"19","first_page":"3902","last_page":"3902"},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T14365","display_name":"Leaf Properties and Growth Measurement","score":0.9990000128746033,"subfield":{"id":"https://openalex.org/subfields/1110","display_name":"Plant Science"},"field":{"id":"https://openalex.org/fields/11","display_name":"Agricultural and Biological Sciences"},"domain":{"id":"https://openalex.org/domains/1","display_name":"Life Sciences"}},"topics":[{"id":"https://openalex.org/T14365","display_name":"Leaf Properties and Growth Measurement","score":0.9990000128746033,"subfield":{"id":"https://openalex.org/subfields/1110","display_name":"Plant Science"},"field":{"id":"https://openalex.org/fields/11","display_name":"Agricultural and Biological Sciences"},"domain":{"id":"https://openalex.org/domains/1","display_name":"Life Sciences"}},{"id":"https://openalex.org/T10111","display_name":"Remote Sensing in Agriculture","score":0.9987999796867371,"subfield":{"id":"https://openalex.org/subfields/2303","display_name":"Ecology"},"field":{"id":"https://openalex.org/fields/23","display_name":"Environmental Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T10640","display_name":"Spectroscopy and Chemometric Analyses","score":0.9854999780654907,"subfield":{"id":"https://openalex.org/subfields/1602","display_name":"Analytical Chemistry"},"field":{"id":"https://openalex.org/fields/16","display_name":"Chemistry"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}}],"keywords":[{"id":"https://openalex.org/keywords/mathematics","display_name":"Mathematics","score":0.5867524743080139},{"id":"https://openalex.org/keywords/univariate","display_name":"Univariate","score":0.5148400664329529},{"id":"https://openalex.org/keywords/chlorophyll","display_name":"Chlorophyll","score":0.499910831451416},{"id":"https://openalex.org/keywords/linear-regression","display_name":"Linear regression","score":0.47040635347366333},{"id":"https://openalex.org/keywords/regression-analysis","display_name":"Regression analysis","score":0.4454171657562256},{"id":"https://openalex.org/keywords/crop","display_name":"Crop","score":0.42886000871658325},{"id":"https://openalex.org/keywords/multivariate-statistics","display_name":"Multivariate statistics","score":0.3937719762325287},{"id":"https://openalex.org/keywords/horticulture","display_name":"Horticulture","score":0.39043885469436646},{"id":"https://openalex.org/keywords/botany","display_name":"Botany","score":0.3676877021789551},{"id":"https://openalex.org/keywords/statistics","display_name":"Statistics","score":0.36661919951438904},{"id":"https://openalex.org/keywords/environmental-science","display_name":"Environmental science","score":0.3273572325706482},{"id":"https://openalex.org/keywords/agronomy","display_name":"Agronomy","score":0.2892240881919861},{"id":"https://openalex.org/keywords/biology","display_name":"Biology","score":0.2687031626701355}],"concepts":[{"id":"https://openalex.org/C33923547","wikidata":"https://www.wikidata.org/wiki/Q395","display_name":"Mathematics","level":0,"score":0.5867524743080139},{"id":"https://openalex.org/C199163554","wikidata":"https://www.wikidata.org/wiki/Q1681619","display_name":"Univariate","level":3,"score":0.5148400664329529},{"id":"https://openalex.org/C2776373379","wikidata":"https://www.wikidata.org/wiki/Q43177","display_name":"Chlorophyll","level":2,"score":0.499910831451416},{"id":"https://openalex.org/C48921125","wikidata":"https://www.wikidata.org/wiki/Q10861030","display_name":"Linear regression","level":2,"score":0.47040635347366333},{"id":"https://openalex.org/C152877465","wikidata":"https://www.wikidata.org/wiki/Q208042","display_name":"Regression analysis","level":2,"score":0.4454171657562256},{"id":"https://openalex.org/C137580998","wikidata":"https://www.wikidata.org/wiki/Q235352","display_name":"Crop","level":2,"score":0.42886000871658325},{"id":"https://openalex.org/C161584116","wikidata":"https://www.wikidata.org/wiki/Q1952580","display_name":"Multivariate statistics","level":2,"score":0.3937719762325287},{"id":"https://openalex.org/C144027150","wikidata":"https://www.wikidata.org/wiki/Q48803","display_name":"Horticulture","level":1,"score":0.39043885469436646},{"id":"https://openalex.org/C59822182","wikidata":"https://www.wikidata.org/wiki/Q441","display_name":"Botany","level":1,"score":0.3676877021789551},{"id":"https://openalex.org/C105795698","wikidata":"https://www.wikidata.org/wiki/Q12483","display_name":"Statistics","level":1,"score":0.36661919951438904},{"id":"https://openalex.org/C39432304","wikidata":"https://www.wikidata.org/wiki/Q188847","display_name":"Environmental science","level":0,"score":0.3273572325706482},{"id":"https://openalex.org/C6557445","wikidata":"https://www.wikidata.org/wiki/Q173113","display_name":"Agronomy","level":1,"score":0.2892240881919861},{"id":"https://openalex.org/C86803240","wikidata":"https://www.wikidata.org/wiki/Q420","display_name":"Biology","level":0,"score":0.2687031626701355}],"mesh":[],"locations_count":3,"locations":[{"id":"doi:10.3390/rs13193902","is_oa":true,"landing_page_url":"https://doi.org/10.3390/rs13193902","pdf_url":"https://www.mdpi.com/2072-4292/13/19/3902/pdf?version=1633673236","source":{"id":"https://openalex.org/S43295729","display_name":"Remote Sensing","issn_l":"2072-4292","issn":["2072-4292"],"is_oa":true,"is_in_doaj":true,"is_core":true,"host_organization":"https://openalex.org/P4310310987","host_organization_name":"Multidisciplinary Digital Publishing Institute","host_organization_lineage":["https://openalex.org/P4310310987"],"host_organization_lineage_names":["Multidisciplinary Digital Publishing Institute"],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Remote Sensing","raw_type":"journal-article"},{"id":"pmh:oai:doaj.org/article:dd8af0e4fd8c4f12b4eca4e0327d7d3f","is_oa":true,"landing_page_url":"https://doaj.org/article/dd8af0e4fd8c4f12b4eca4e0327d7d3f","pdf_url":null,"source":{"id":"https://openalex.org/S112646816","display_name":"SHILAP Revista de lepidopterolog\u00eda","issn_l":"0300-5267","issn":["0300-5267","2340-4078"],"is_oa":true,"is_in_doaj":true,"is_core":false,"host_organization":null,"host_organization_name":null,"host_organization_lineage":[],"host_organization_lineage_names":[],"type":"journal"},"license":"cc-by-sa","license_id":"https://openalex.org/licenses/cc-by-sa","version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"Remote Sensing, Vol 13, Iss 19, p 3902 (2021)","raw_type":"article"},{"id":"pmh:oai:mdpi.com:/2072-4292/13/19/3902/","is_oa":true,"landing_page_url":"https://dx.doi.org/10.3390/rs13193902","pdf_url":null,"source":{"id":"https://openalex.org/S4306400947","display_name":"MDPI (MDPI AG)","issn_l":null,"issn":null,"is_oa":true,"is_in_doaj":false,"is_core":false,"host_organization":"https://openalex.org/I4210097602","host_organization_name":"Multidisciplinary Digital Publishing Institute (Switzerland)","host_organization_lineage":["https://openalex.org/I4210097602"],"host_organization_lineage_names":[],"type":"repository"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"Remote Sensing; Volume 13; Issue 19; Pages: 3902","raw_type":"Text"}],"best_oa_location":{"id":"doi:10.3390/rs13193902","is_oa":true,"landing_page_url":"https://doi.org/10.3390/rs13193902","pdf_url":"https://www.mdpi.com/2072-4292/13/19/3902/pdf?version=1633673236","source":{"id":"https://openalex.org/S43295729","display_name":"Remote Sensing","issn_l":"2072-4292","issn":["2072-4292"],"is_oa":true,"is_in_doaj":true,"is_core":true,"host_organization":"https://openalex.org/P4310310987","host_organization_name":"Multidisciplinary Digital Publishing Institute","host_organization_lineage":["https://openalex.org/P4310310987"],"host_organization_lineage_names":["Multidisciplinary Digital Publishing Institute"],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Remote Sensing","raw_type":"journal-article"},"sustainable_development_goals":[{"score":0.6000000238418579,"id":"https://metadata.un.org/sdg/15","display_name":"Life in Land"}],"awards":[],"funders":[],"has_content":{"grobid_xml":true,"pdf":true},"content_urls":{"pdf":"https://content.openalex.org/works/W3206966913.pdf","grobid_xml":"https://content.openalex.org/works/W3206966913.grobid-xml"},"referenced_works_count":58,"referenced_works":["https://openalex.org/W1964357740","https://openalex.org/W1974416151","https://openalex.org/W1982216854","https://openalex.org/W1996361027","https://openalex.org/W1996379195","https://openalex.org/W1999558009","https://openalex.org/W2000613913","https://openalex.org/W2008549721","https://openalex.org/W2011475440","https://openalex.org/W2017903276","https://openalex.org/W2018672259","https://openalex.org/W2020216002","https://openalex.org/W2020473914","https://openalex.org/W2028145168","https://openalex.org/W2029567272","https://openalex.org/W2030233869","https://openalex.org/W2052256290","https://openalex.org/W2055456375","https://openalex.org/W2057084393","https://openalex.org/W2066724429","https://openalex.org/W2078996926","https://openalex.org/W2089441588","https://openalex.org/W2098247895","https://openalex.org/W2101234009","https://openalex.org/W2109006150","https://openalex.org/W2111947859","https://openalex.org/W2127352506","https://openalex.org/W2151591509","https://openalex.org/W2317582304","https://openalex.org/W2392664124","https://openalex.org/W2593914677","https://openalex.org/W2598497520","https://openalex.org/W2609044008","https://openalex.org/W2609881461","https://openalex.org/W2770955947","https://openalex.org/W2800270701","https://openalex.org/W2903662845","https://openalex.org/W2911595297","https://openalex.org/W2911964244","https://openalex.org/W2915540904","https://openalex.org/W2935876239","https://openalex.org/W2940512980","https://openalex.org/W2948615590","https://openalex.org/W2998577031","https://openalex.org/W3019576236","https://openalex.org/W3087149783","https://openalex.org/W3096629639","https://openalex.org/W3158402280","https://openalex.org/W3213429084","https://openalex.org/W4319289039","https://openalex.org/W6650335020","https://openalex.org/W6657285961","https://openalex.org/W6675354045","https://openalex.org/W6682129855","https://openalex.org/W6711800648","https://openalex.org/W6750796189","https://openalex.org/W6772375692","https://openalex.org/W6849296793"],"related_works":["https://openalex.org/W1828158523","https://openalex.org/W2049578243","https://openalex.org/W2000145235","https://openalex.org/W2122079181","https://openalex.org/W1985848810","https://openalex.org/W2889939530","https://openalex.org/W3121881699","https://openalex.org/W2748838164","https://openalex.org/W2066015000","https://openalex.org/W2912721996"],"abstract_inverted_index":{"Leaf":[0],"chlorophyll":[1,33,58,188],"content":[2],"(LCC)":[3],"is":[4,35],"one":[5],"of":[6,18,26,38,47,56,65,78,130,212,228,238,282,329],"the":[7,24,45,48,54,76,120,123,181,201,225,234,243,252,283,296,310,323],"most":[8],"important":[9],"factors":[10],"affecting":[11],"photosynthetic":[12],"capacity":[13],"and":[14,28,91,110,127,139,148,163,166,170,172,192,204,221,240,242,248,269,326],"nitrogen":[15],"status,":[16],"both":[17],"which":[19],"influence":[20],"crop":[21],"harvest.":[22],"However,":[23,251],"development":[25],"rapid":[27],"nondestructive":[29],"methods":[30],"for":[31,74,306,335],"leaf":[32,57,187],"estimation":[34,55],"a":[36,303],"topic":[37],"much":[39],"interest.":[40],"Hence,":[41],"this":[42,66],"study":[43,67],"explored":[44],"use":[46],"machine":[49,316],"learning":[50,317],"approach":[51],"to":[52,69],"enhance":[53],"from":[59,119],"spectral":[60],"reflectance":[61],"data.":[62],"The":[63,209,219,262,279],"objective":[64],"was":[68,256,265,271,293],"evaluate":[70],"four":[71],"different":[72,213,229,276],"approaches":[73],"estimating":[75],"LCC":[77,162,165,171,226],"apple":[79,131,154],"tree":[80,155],"leaves":[81,121],"at":[82,200,275],"five":[83,133],"growth":[84,93,141,206,214,230,277,285,324],"stages":[85,215,231],"(the":[86],"1st,":[87],"2nd,":[88,136],"3rd,":[89,137,202,203],"4th":[90,138,205],"5th":[92,140],"stages):":[94],"(1)":[95],"univariate":[96],"linear":[97,102],"regression":[98,103,108],"(ULR);":[99],"(2)":[100],"multivariate":[101],"(MLR);":[104],"(3)":[105],"support":[106,334],"vector":[107],"(SVR);":[109],"(4)":[111],"random":[112],"forest":[113],"(RF)":[114],"regression.":[115],"Samples":[116],"were":[117,150,216,246],"collected":[118],"on":[122,315],"eastern,":[124],"western,":[125],"southern":[126],"northern":[128],"sides":[129],"trees":[132],"times":[134],"(1st,":[135],"stages)":[142],"over":[143],"three":[144,173],"consecutive":[145],"years":[146],"(2016\u20132018),":[147],"experiments":[149],"conducted":[151],"in":[152,224],"10\u201320-year-old":[153],"orchards.":[156],"Correlation":[157],"analysis":[158],"results":[159],"showed":[160],"that":[161,331],"ST,":[164],"vegetation":[167],"indices":[168],"(VIs),":[169],"edge":[174],"parameters":[175,328],"(TEP)":[176],"had":[177],"high":[178],"correlations":[179],"with":[180,295],"first-order":[182],"differential":[183],"spectrum":[184],"(FODS)":[185],"(0.86),":[186],"index":[189],"(LCI)":[190],"(0.87),":[191],"(SDr":[193,196],"\u2212":[194],"SDb)/":[195],"+":[197],"SDb)":[198],"(0.88)":[199],"stages,":[207],"respectively.":[208,250],"prediction":[210,280],"models":[211,223,313],"relatively":[217],"good.":[218],"MLR":[220],"SVR":[222],"assessment":[227],"only":[232],"reached":[233],"highest":[235],"R2":[236,263],"values":[237],"0.79":[239],"0.82,":[241],"lowest":[244],"RMSEs":[245],"2.27":[247],"2.02,":[249],"RF":[253,297],"model":[254],"evaluation":[255],"significantly":[257],"better":[258],"than":[259,267,273],"above":[260],"models.":[261],"value":[264],"greater":[266],"0.94":[268],"RMSE":[270,290],"less":[272],"1.37":[274],"stages.":[278],"accuracy":[281],"1st":[284],"stage":[286],"(R2":[287],"=":[288,291],"0.96,":[289],"0.95)":[292],"best":[294],"model.":[298],"This":[299],"result":[300],"could":[301],"provide":[302,332],"theoretical":[304],"basis":[305],"orchard":[307,337],"management.":[308,338],"In":[309],"future,":[311],"more":[312],"based":[314],"techniques":[318],"should":[319],"be":[320],"developed":[321],"using":[322],"information":[325],"physiological":[327],"orchards":[330],"technical":[333],"intelligent":[336]},"counts_by_year":[{"year":2026,"cited_by_count":3},{"year":2025,"cited_by_count":8},{"year":2024,"cited_by_count":20},{"year":2023,"cited_by_count":13},{"year":2022,"cited_by_count":8}],"updated_date":"2026-03-27T05:58:40.876381","created_date":"2025-10-10T00:00:00"}