<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0187-7380</journal-id>
<journal-title><![CDATA[Revista fitotecnia mexicana]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. fitotec. mex]]></abbrev-journal-title>
<issn>0187-7380</issn>
<publisher>
<publisher-name><![CDATA[Sociedad Mexicana de Fitogenética A.C.]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0187-73802020000400399</article-id>
<article-id pub-id-type="doi">10.35196/rfm.2020.4.399</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Estimación de la fracción de cobertura de la vegetación en maíz (Zea mays) mediante imágenes digitales tomadas por un vehículo aéreo no tripulado (UAV)]]></article-title>
<article-title xml:lang="en"><![CDATA[Estimation of the vegetation coverage fraction in corn (Zea mays) through digital images taken by an unmanned aerial vehicle (UAV)]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[García-Martínez]]></surname>
<given-names><![CDATA[Héctor]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Flores-Magdaleno]]></surname>
<given-names><![CDATA[Héctor]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Khalil-Gardezi]]></surname>
<given-names><![CDATA[Abdul]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Ascencio-Hernández]]></surname>
<given-names><![CDATA[Roberto]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Tijerina-Chávez]]></surname>
<given-names><![CDATA[Leonardo]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Vázquez-Peña]]></surname>
<given-names><![CDATA[Mario A.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Mancilla-Villa]]></surname>
<given-names><![CDATA[Oscar R.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Colegio de Postgraduados  ]]></institution>
<addr-line><![CDATA[Texcoco Estado de México]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Universidad Autónoma Chapingo Departamento de Irrigación ]]></institution>
<addr-line><![CDATA[Texcoco Estado de México]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af3">
<institution><![CDATA[,Universidad de Guadalajara Centro Universitario de la Costa Sur ]]></institution>
<addr-line><![CDATA[Autlán Jalisco]]></addr-line>
<country>Mexico</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>12</month>
<year>2020</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>12</month>
<year>2020</year>
</pub-date>
<volume>43</volume>
<numero>4</numero>
<fpage>399</fpage>
<lpage>409</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0187-73802020000400399&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0187-73802020000400399&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0187-73802020000400399&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen La fracción de cobertura de la vegetación es una variable importante en el monitoreo de cultivos que se relaciona con características biofísicas como la densidad, la fenología, el índice de área foliar, la germinación, la capacidad fotosintética del follaje, la evapotranspiración, la productividad y el rendimiento de los cultivos. El objetivo de este estudio fue estimar la fracción de cobertura vegetal durante el desarrollo del cultivo de maíz a partir de imágenes tomadas por un sensor que captura información en el espectro del rojo, verde y azul (RGB) montado en un vehículo aéreo no tripulado, con índices de vegetación y métodos de umbralización. Se realizaron seis vuelos, lo que generó seis ortomosaicos durante el desarrollo del cultivo. La captura de la imagen fue a 30 m de altura sobre el nivel del suelo, con resoluciones de 0.75 a 0.80 cm/pixel. Para la extracción de la vegetación y transformación de los ortomosaicos a escala de grises se emplearon cuatro índices de vegetación (IV): índice de verdor triangular (TGI), índice exceso de verde (EXG), índice de resistencia atmosférica visible (VARI) e índice de diferencia normalizado verde-rojo (NGRDI). La umbralización se realizó con los algoritmos Otsu, IsoData, Fuzzy y conservación de momentos a cada imagen en escala de grises generada con los IV para separar y clasificar los pixeles de las imágenes en dos clases, suelo y vegetación. Los índices utilizados para extraer la vegetación mostraron alta precisión en las primeras etapas de desarrollo, por lo que es posible utilizarlos para conocer la germinación, densidad y vigor inicial del cultivo. Se encontró que el índice EXG presentó errores de 2.2 a 17.8 % en la estimación de la fracción de cobertura de la vegetación durante el desarrollo del cultivo; errores menores al 5 % se obtuvieron mediante el umbral calculado con el método Fuzzy hasta los 58 días después de siembra. El uso de las imágenes digitales de alta resolución desde el vehículo aéreo no tripulado (UAV) permitió estimar la cobertura vegetal con errores menores al 5 % en las primeras etapas de desarrollo del cultivo del maíz.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[Summary The vegetation cover fraction is an important variable in crop monitoring that is related to biophysical characteristics such as density, phenology, leaf area index, germination, photosynthetic capacity of foliage, evapotranspiration, productivity and crop yield. The aim of this study was to estimate the vegetation cover fraction during the development of the maize crop, from images taken by a sensor that captures information in the spectrum of red, green, and blue (RGB), mounted on an unmanned aerial vehicle, with vegetation indices and thresholding methods. Six flights were made, which generated six orthomosaics during the development of the crop. The image capture was 30 m above ground level, with resolutions of 0.75 to 0.80 cm/pixel. For the extraction of the vegetation and transformation of the orthomosaics to grayscale, four vegetation indices (IV): triangular greenness index (TGI), excess green index (ExG), visible atmospheric resistance index (VARI) and normalized green-red difference index (NGRDI) were used. Thresholding was performed with the Otsu, IsoData, Fuzzy, and momentum conservation algorithms for each grayscale image generated with the IVs to separate and classify the pixels of the images into two classes, soil and vegetation. The indices used to extract the vegetation showed high precision in the early stages of development; thus, it is possible to use them to know the germination, density, and early vigor of the crop. It was found that the EXG index presented errors from 2.2 to 17.8 % in the estimation of the vegetation cover fraction during the development of the crop; errors less than 5 % were obtained through the threshold calculated with the Fuzzy method up to 58 days after planting. The use of high-resolution digital images from the unmanned aerial vehicle (UAV) allowed estimating the vegetation cover with errors of less than 5 % in the early stages of the development of the maize crop.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[Zea mays]]></kwd>
<kwd lng="es"><![CDATA[fracción de cobertura]]></kwd>
<kwd lng="es"><![CDATA[imágenes]]></kwd>
<kwd lng="es"><![CDATA[índices de vegetación]]></kwd>
<kwd lng="es"><![CDATA[UAV]]></kwd>
<kwd lng="es"><![CDATA[umbralización]]></kwd>
<kwd lng="en"><![CDATA[Zea mays]]></kwd>
<kwd lng="en"><![CDATA[coverage fraction]]></kwd>
<kwd lng="en"><![CDATA[images]]></kwd>
<kwd lng="en"><![CDATA[thresholding]]></kwd>
<kwd lng="en"><![CDATA[UAV]]></kwd>
<kwd lng="en"><![CDATA[vegetation index]]></kwd>
</kwd-group>
</article-meta>
</front><back>
<ref-list>
<ref id="B1">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Allan]]></surname>
<given-names><![CDATA[B. M.]]></given-names>
</name>
<name>
<surname><![CDATA[Ierodiaconou]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
<name>
<surname><![CDATA[Hoskins]]></surname>
<given-names><![CDATA[A. J.]]></given-names>
</name>
<name>
<surname><![CDATA[Arnould]]></surname>
<given-names><![CDATA[J. P. Y.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[A rapid UAV method for assessing body condition in fur seals]]></article-title>
<source><![CDATA[Drones]]></source>
<year>2019</year>
<volume>3</volume>
<page-range>24</page-range></nlm-citation>
</ref>
<ref id="B2">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[De la Casa]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Ovando]]></surname>
<given-names><![CDATA[G.]]></given-names>
</name>
<name>
<surname><![CDATA[Bressanini]]></surname>
<given-names><![CDATA[L.]]></given-names>
</name>
<name>
<surname><![CDATA[Martínez]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Rodríguez]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Eficiencia en el uso de la radiación en papa estimada a partir de la cobertura del follaje]]></article-title>
<source><![CDATA[AgriScientia]]></source>
<year>2011</year>
<volume>28</volume>
<page-range>21-30</page-range></nlm-citation>
</ref>
<ref id="B3">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Choi]]></surname>
<given-names><![CDATA[S. K.]]></given-names>
</name>
<name>
<surname><![CDATA[Lee]]></surname>
<given-names><![CDATA[S. K.]]></given-names>
</name>
<name>
<surname><![CDATA[Jung]]></surname>
<given-names><![CDATA[S. H.]]></given-names>
</name>
<name>
<surname><![CDATA[Choi]]></surname>
<given-names><![CDATA[J. W.]]></given-names>
</name>
<name>
<surname><![CDATA[Choi]]></surname>
<given-names><![CDATA[D. Y.]]></given-names>
</name>
<name>
<surname><![CDATA[Chun]]></surname>
<given-names><![CDATA[S. J.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Estimation of fractional vegetation cover in sand dunes using multi-spectral images from fixed-wing UAV]]></article-title>
<source><![CDATA[Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography]]></source>
<year>2016</year>
<volume>34</volume>
<page-range>431-41</page-range></nlm-citation>
</ref>
<ref id="B4">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Colomina]]></surname>
<given-names><![CDATA[I.]]></given-names>
</name>
<name>
<surname><![CDATA[Molina]]></surname>
<given-names><![CDATA[P.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Unmanned aerial systems for photogrammetry and remote sensing: a review]]></article-title>
<source><![CDATA[ISPRS Journal of Photogrammetry and Remote Sensing]]></source>
<year>2014</year>
<volume>92</volume>
<page-range>79-97</page-range></nlm-citation>
</ref>
<ref id="B5">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Dandois]]></surname>
<given-names><![CDATA[J. P.]]></given-names>
</name>
<name>
<surname><![CDATA[Olano]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[Ellis]]></surname>
<given-names><![CDATA[E. C.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Optimal altitude, overlap, and weather conditions for computer vision UAV estimates of forest structure]]></article-title>
<source><![CDATA[Remote Sensing]]></source>
<year>2015</year>
<volume>7</volume>
<page-range>13895-920</page-range></nlm-citation>
</ref>
<ref id="B6">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Fang]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
<name>
<surname><![CDATA[Tang]]></surname>
<given-names><![CDATA[W.]]></given-names>
</name>
<name>
<surname><![CDATA[Peng]]></surname>
<given-names><![CDATA[Y.]]></given-names>
</name>
<name>
<surname><![CDATA[Gong]]></surname>
<given-names><![CDATA[Y.]]></given-names>
</name>
<name>
<surname><![CDATA[Dai]]></surname>
<given-names><![CDATA[C.]]></given-names>
</name>
<name>
<surname><![CDATA[Chai]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[Liu]]></surname>
<given-names><![CDATA[K.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Remote estimation of vegetation fraction and flower fraction in oilseed rape with unmanned aerial vehicle data]]></article-title>
<source><![CDATA[Remote Sensing]]></source>
<year>2016</year>
<volume>8</volume>
<page-range>416</page-range></nlm-citation>
</ref>
<ref id="B7">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[García-Martínez]]></surname>
<given-names><![CDATA[H.]]></given-names>
</name>
<name>
<surname><![CDATA[Flores-Magdaleno]]></surname>
<given-names><![CDATA[H.]]></given-names>
</name>
<name>
<surname><![CDATA[Ascencio-Hernández]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[Khalil-Gardezi]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Tijerina-Chávez]]></surname>
<given-names><![CDATA[L.]]></given-names>
</name>
<name>
<surname><![CDATA[Mancilla-Villa]]></surname>
<given-names><![CDATA[O. R.]]></given-names>
</name>
<name>
<surname><![CDATA[Vázquez-Peña]]></surname>
<given-names><![CDATA[M. A.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Corn grain yield estimation from vegetation indices, canopy cover, plant density, and a neural network using multispectral and RGB images acquired with unmanned aerial vehicles]]></article-title>
<source><![CDATA[Agriculture]]></source>
<year>2020</year>
<volume>10</volume>
<page-range>277</page-range></nlm-citation>
</ref>
<ref id="B8">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Gitelson]]></surname>
<given-names><![CDATA[A. A.]]></given-names>
</name>
<name>
<surname><![CDATA[Kaufman]]></surname>
<given-names><![CDATA[Y. J.]]></given-names>
</name>
<name>
<surname><![CDATA[Stark]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[Rundquist]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Novel algorithms for remote estimation of vegetation fraction]]></article-title>
<source><![CDATA[Remote Sensing of Environment]]></source>
<year>2002</year>
<volume>80</volume>
<page-range>76-87</page-range></nlm-citation>
</ref>
<ref id="B9">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Guijarro]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[Pajares]]></surname>
<given-names><![CDATA[G.]]></given-names>
</name>
<name>
<surname><![CDATA[Riomoros]]></surname>
<given-names><![CDATA[I.]]></given-names>
</name>
<name>
<surname><![CDATA[Herrera]]></surname>
<given-names><![CDATA[P. J.]]></given-names>
</name>
<name>
<surname><![CDATA[Burgos-Artizzu]]></surname>
<given-names><![CDATA[X. P.]]></given-names>
</name>
<name>
<surname><![CDATA[Ribeiro]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Automatic segmentation of relevant textures in agricultural images]]></article-title>
<source><![CDATA[Computers and Electronics in Agriculture]]></source>
<year>2011</year>
<volume>75</volume>
<page-range>75-83</page-range></nlm-citation>
</ref>
<ref id="B10">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Gupta]]></surname>
<given-names><![CDATA[S. K.]]></given-names>
</name>
<name>
<surname><![CDATA[Shukla]]></surname>
<given-names><![CDATA[D. P.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Application of drone for landslide mapping, dimension estimation and its 3D reconstruction]]></article-title>
<source><![CDATA[Journal of the Indian Society of Remote Sensing]]></source>
<year>2018</year>
<volume>46</volume>
<page-range>903-14</page-range></nlm-citation>
</ref>
<ref id="B11">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Huang]]></surname>
<given-names><![CDATA[L. K.]]></given-names>
</name>
<name>
<surname><![CDATA[Wang]]></surname>
<given-names><![CDATA[M. J. J.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Image thresholding by minimizing the measures of fuzziness]]></article-title>
<source><![CDATA[Pattern Recognition]]></source>
<year>1995</year>
<volume>28</volume>
<page-range>41-51</page-range></nlm-citation>
</ref>
<ref id="B12">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Hunt]]></surname>
<given-names><![CDATA[E. R.]]></given-names>
</name>
<name>
<surname><![CDATA[Cavigelli]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[Daughtry]]></surname>
<given-names><![CDATA[C. S. T.]]></given-names>
</name>
<name>
<surname><![CDATA[Mcmurtrey]]></surname>
<given-names><![CDATA[J. E.]]></given-names>
</name>
<name>
<surname><![CDATA[Walthall]]></surname>
<given-names><![CDATA[C. L.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Evaluation of digital photography from model aircraft for remote sensing of crop biomass and nitrogen status]]></article-title>
<source><![CDATA[Precision Agriculture]]></source>
<year>2005</year>
<volume>6</volume>
<page-range>359-78</page-range></nlm-citation>
</ref>
<ref id="B13">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Hunt]]></surname>
<given-names><![CDATA[E. R.]]></given-names>
</name>
<name>
<surname><![CDATA[Daughtry]]></surname>
<given-names><![CDATA[C. S. T.]]></given-names>
</name>
<name>
<surname><![CDATA[Eitel]]></surname>
<given-names><![CDATA[J. U. H.]]></given-names>
</name>
<name>
<surname><![CDATA[Long]]></surname>
<given-names><![CDATA[D. S.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Remote sensing leaf chlorophyll content using a visible band index]]></article-title>
<source><![CDATA[Agronomy Journal]]></source>
<year>2011</year>
<volume>103</volume>
<page-range>1090-9</page-range></nlm-citation>
</ref>
<ref id="B14">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Hunt]]></surname>
<given-names><![CDATA[E. R.]]></given-names>
</name>
<name>
<surname><![CDATA[Doraiswamy]]></surname>
<given-names><![CDATA[P. C.]]></given-names>
</name>
<name>
<surname><![CDATA[McMurtrey]]></surname>
<given-names><![CDATA[J. E.]]></given-names>
</name>
<name>
<surname><![CDATA[Daughtry]]></surname>
<given-names><![CDATA[C. S. T.]]></given-names>
</name>
<name>
<surname><![CDATA[Perry]]></surname>
<given-names><![CDATA[E. M.]]></given-names>
</name>
<name>
<surname><![CDATA[Akhmedov]]></surname>
<given-names><![CDATA[B.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[A visible band index for remote sensing leaf chlorophyll content at the canopy scale]]></article-title>
<source><![CDATA[International Journal of Applied Earth Observation and Geoinformation]]></source>
<year>2013</year>
<volume>21</volume>
<page-range>103-12</page-range></nlm-citation>
</ref>
<ref id="B15">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Landini]]></surname>
<given-names><![CDATA[G.]]></given-names>
</name>
<name>
<surname><![CDATA[Randell]]></surname>
<given-names><![CDATA[D.A.]]></given-names>
</name>
<name>
<surname><![CDATA[Fouad]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
<name>
<surname><![CDATA[Galton]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Automatic thresholding from the gradients of region boundaries]]></article-title>
<source><![CDATA[Journal of Microscopy]]></source>
<year>2017</year>
<volume>265</volume>
<page-range>185-95</page-range></nlm-citation>
</ref>
<ref id="B16">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Lucieer]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Jong]]></surname>
<given-names><![CDATA[S. M. de]]></given-names>
</name>
<name>
<surname><![CDATA[Turner]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Mapping landslide displacements using Structure from Motion (SfM) and image correlation of multi-temporal UAV photography]]></article-title>
<source><![CDATA[Progress in Physical Geography: Earth and Environment]]></source>
<year>2014</year>
<volume>38</volume>
<page-range>97-116</page-range></nlm-citation>
</ref>
<ref id="B17">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Macedo-Cruz]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Pajares]]></surname>
<given-names><![CDATA[G.]]></given-names>
</name>
<name>
<surname><![CDATA[Santos]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[Villegas-Romero]]></surname>
<given-names><![CDATA[I.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Digital image sensor-based assessment of the status of oat (Avena sativa L.) crops after frost damage]]></article-title>
<source><![CDATA[Sensors]]></source>
<year>2011</year>
<volume>11</volume>
<page-range>6015-36</page-range></nlm-citation>
</ref>
<ref id="B18">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Macedo-Cruz]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Pajares-Martinsanz]]></surname>
<given-names><![CDATA[G.]]></given-names>
</name>
<name>
<surname><![CDATA[Santos-Peñas]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Clasificación no supervisada con imágenes a color de cobertura terrestre]]></article-title>
<source><![CDATA[Agrociencia]]></source>
<year>2010</year>
<volume>44</volume>
<page-range>711-22</page-range></nlm-citation>
</ref>
<ref id="B19">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Maes]]></surname>
<given-names><![CDATA[W. H.]]></given-names>
</name>
<name>
<surname><![CDATA[Steppe]]></surname>
<given-names><![CDATA[K.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Perspectives for remote sensing with unmanned aerial vehicles in precision agriculture]]></article-title>
<source><![CDATA[Trends in Plant Science]]></source>
<year>2019</year>
<volume>24</volume>
<page-range>152-64</page-range></nlm-citation>
</ref>
<ref id="B20">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Otsu]]></surname>
<given-names><![CDATA[N.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[A threshold selection method from gray-level histograms]]></article-title>
<source><![CDATA[IEEE Transactions on Systems, Man, and Cybernetics]]></source>
<year>1979</year>
<volume>9</volume>
<page-range>62-6</page-range></nlm-citation>
</ref>
<ref id="B21">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Paoletti]]></surname>
<given-names><![CDATA[M. E.]]></given-names>
</name>
<name>
<surname><![CDATA[Haut]]></surname>
<given-names><![CDATA[J. M.]]></given-names>
</name>
<name>
<surname><![CDATA[Plaza]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Plaza]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Estudio comparativo de técnicas de clasificación de imágenes hiperespectrales]]></article-title>
<source><![CDATA[Revista Iberoamericana de Automática e Informática Industrial]]></source>
<year>2019</year>
<volume>16</volume>
<page-range>129-37</page-range></nlm-citation>
</ref>
<ref id="B22">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Raes]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
<name>
<surname><![CDATA[Steduto]]></surname>
<given-names><![CDATA[P.]]></given-names>
</name>
<name>
<surname><![CDATA[Hsiao]]></surname>
<given-names><![CDATA[T. C.]]></given-names>
</name>
<name>
<surname><![CDATA[Fereres]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[AquaCrop - the FAO crop model to simulate yield response to water: II. Main algorithms and software description]]></article-title>
<source><![CDATA[Agronomy Journal]]></source>
<year>2009</year>
<volume>101</volume>
<page-range>438-47</page-range></nlm-citation>
</ref>
<ref id="B23">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Ridler]]></surname>
<given-names><![CDATA[T. W.]]></given-names>
</name>
<name>
<surname><![CDATA[Calvard]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Picture thresholding using an iterative selection method]]></article-title>
<source><![CDATA[IEEE Transactions on Systems, Man, and Cybernetics]]></source>
<year>1978</year>
<volume>8</volume>
<page-range>630-2</page-range></nlm-citation>
</ref>
<ref id="B24">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Rodríguez]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Casa]]></surname>
<given-names><![CDATA[A. C. de la]]></given-names>
</name>
<name>
<surname><![CDATA[Bressanini]]></surname>
<given-names><![CDATA[L.]]></given-names>
</name>
<name>
<surname><![CDATA[Accietto]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[Ovando]]></surname>
<given-names><![CDATA[G.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Determinación del área foliar en papa (Solanum tuberosum L., var. Spunta) por medio de fotografías digitales conociendo la relación entre el número de pixeles y la altura de adquisición]]></article-title>
<source><![CDATA[Revista Brasileira de Agrometeorología]]></source>
<year>2000</year>
<volume>8</volume>
<page-range>215-21</page-range></nlm-citation>
</ref>
<ref id="B25">
<nlm-citation citation-type="confpro">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Rundquist]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
<name>
<surname><![CDATA[Gitelson]]></surname>
<given-names><![CDATA[A. A.]]></given-names>
</name>
<name>
<surname><![CDATA[Derry]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
<name>
<surname><![CDATA[Ramirez]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Stark]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[Keydan]]></surname>
<given-names><![CDATA[G. P.]]></given-names>
</name>
<name>
<surname><![CDATA[Grenier]]></surname>
<given-names><![CDATA[G.]]></given-names>
</name>
<name>
<surname><![CDATA[lackmore]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
</person-group>
<source><![CDATA[Remote estimation of vegetation fraction in corn canopies]]></source>
<year>2001</year>
<conf-name><![CDATA[ Proceedings of the Third European Conference on Precision Agriculture]]></conf-name>
<conf-loc> </conf-loc>
<page-range>301-6</page-range><publisher-loc><![CDATA[Montpelier, France ]]></publisher-loc>
<publisher-name><![CDATA[International Society of Precision Agriculture]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B26">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Schirrmann]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[Giebel]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Gleiniger]]></surname>
<given-names><![CDATA[F.]]></given-names>
</name>
<name>
<surname><![CDATA[Pflanz]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[Lentschke]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Dammer]]></surname>
<given-names><![CDATA[K. H.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Monitoring agronomic parameters of winter wheat crops with low-cost UAV imagery]]></article-title>
<source><![CDATA[Remote Sensing]]></source>
<year>2016</year>
<volume>8</volume>
<page-range>706</page-range></nlm-citation>
</ref>
<ref id="B27">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Seifert]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Seifert]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
<name>
<surname><![CDATA[Vogt]]></surname>
<given-names><![CDATA[H.]]></given-names>
</name>
<name>
<surname><![CDATA[Drew]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
<name>
<surname><![CDATA[Aardt]]></surname>
<given-names><![CDATA[J. van]]></given-names>
</name>
<name>
<surname><![CDATA[Kunneke]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Seifert]]></surname>
<given-names><![CDATA[T.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Influence of drone altitude, image overlap, and optical sensor resolution on multi-view reconstruction of forest images]]></article-title>
<source><![CDATA[Remote Sensing]]></source>
<year>2019</year>
<volume>11</volume>
<page-range>1252</page-range></nlm-citation>
</ref>
<ref id="B28">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Steven]]></surname>
<given-names><![CDATA[M. D.]]></given-names>
</name>
<name>
<surname><![CDATA[Biscoe]]></surname>
<given-names><![CDATA[P. V.]]></given-names>
</name>
<name>
<surname><![CDATA[Jaggard]]></surname>
<given-names><![CDATA[K. W.]]></given-names>
</name>
<name>
<surname><![CDATA[Paruntu]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Foliage cover and radiation interception]]></article-title>
<source><![CDATA[Field Crops Research]]></source>
<year>1986</year>
<volume>13</volume>
<page-range>75-87</page-range></nlm-citation>
</ref>
<ref id="B29">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Torres-Sánchez]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Peña]]></surname>
<given-names><![CDATA[J. M.]]></given-names>
</name>
<name>
<surname><![CDATA[Castro]]></surname>
<given-names><![CDATA[A. I. de]]></given-names>
</name>
<name>
<surname><![CDATA[López-Granados]]></surname>
<given-names><![CDATA[F.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Multi-temporal mapping of the vegetation fraction in earlyseason wheat fields using images from UAV]]></article-title>
<source><![CDATA[Computers and Electronics in Agriculture]]></source>
<year>2014</year>
<volume>103</volume>
<page-range>104-13</page-range></nlm-citation>
</ref>
<ref id="B30">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Tsai]]></surname>
<given-names><![CDATA[W. H.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Moment-preserving thresolding: a new approach]]></article-title>
<source><![CDATA[Computer Vision, Graphics, and Image Processing]]></source>
<year>1985</year>
<volume>29</volume>
<page-range>377-93</page-range></nlm-citation>
</ref>
<ref id="B31">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Tu]]></surname>
<given-names><![CDATA[Y. H.]]></given-names>
</name>
<name>
<surname><![CDATA[Phinn]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
<name>
<surname><![CDATA[Johansen]]></surname>
<given-names><![CDATA[K.]]></given-names>
</name>
<name>
<surname><![CDATA[Robson]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Wu]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Optimising drone flight planning for measuring horticultural tree crop structure]]></article-title>
<source><![CDATA[ISPRS Journal of Photogrammetry and Remote Sensing]]></source>
<year>2020</year>
<volume>160</volume>
<page-range>83-96</page-range></nlm-citation>
</ref>
<ref id="B32">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Viña]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Gitelson]]></surname>
<given-names><![CDATA[A. A.]]></given-names>
</name>
<name>
<surname><![CDATA[Rundquist]]></surname>
<given-names><![CDATA[D. C.]]></given-names>
</name>
<name>
<surname><![CDATA[Keydan]]></surname>
<given-names><![CDATA[G.]]></given-names>
</name>
<name>
<surname><![CDATA[Leavitt]]></surname>
<given-names><![CDATA[B.]]></given-names>
</name>
<name>
<surname><![CDATA[Schepers]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Monitoring maize (Zea mays L.) phenology with remote sensing]]></article-title>
<source><![CDATA[Agronomy Journal]]></source>
<year>2004</year>
<volume>96</volume>
<page-range>1139-47</page-range></nlm-citation>
</ref>
<ref id="B33">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Woebbecke]]></surname>
<given-names><![CDATA[D. M.]]></given-names>
</name>
<name>
<surname><![CDATA[Meyer]]></surname>
<given-names><![CDATA[G. E.]]></given-names>
</name>
<name>
<surname><![CDATA[Bargen]]></surname>
<given-names><![CDATA[K. Von]]></given-names>
</name>
<name>
<surname><![CDATA[Mortensen]]></surname>
<given-names><![CDATA[D. A.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Color indices for weed identification under various soil, residue, and lighting conditions]]></article-title>
<source><![CDATA[Transactions of the ASAE]]></source>
<year>1995</year>
<volume>38</volume>
<page-range>259-69</page-range></nlm-citation>
</ref>
<ref id="B34">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Yao]]></surname>
<given-names><![CDATA[H.]]></given-names>
</name>
<name>
<surname><![CDATA[Qin]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[Chen]]></surname>
<given-names><![CDATA[X.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Unmanned aerial vehicle for remote sensing applications - A review]]></article-title>
<source><![CDATA[Remote Sensing]]></source>
<year>2019</year>
<volume>11</volume>
<page-range>1443</page-range></nlm-citation>
</ref>
</ref-list>
</back>
</article>
