<?xml version="1.0" encoding="utf-8"?>
<?xml-stylesheet href="CIGAL-CUS_2011_onglets.xsl" type="text/xsl"?>
<gmd:MD_Metadata xmlns:gco="http://www.isotc211.org/2005/gco" xmlns:gmd="http://www.isotc211.org/2005/gmd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.isotc211.org/2005/gmd http://schemas.opengis.net/iso/19139/20060504/gmd/gmd.xsd">
<gmd:fileIdentifier><gco:CharacterString>FR-130005457-20050921_CASI_HS_2m_Stras_UTM_P2</gco:CharacterString></gmd:fileIdentifier>
<gmd:language><gmd:LanguageCode codeList="http://www.loc.gov/standards/iso639-2/" codeListValue="fre">fre</gmd:LanguageCode></gmd:language>
<gmd:characterSet><gmd:MD_CharacterSetCode codeList="http://www.isotc211.org/2005/resources/codeList.xml#MD_CharacterSetCode" codeListValue="utf8">utf8</gmd:MD_CharacterSetCode></gmd:characterSet>
<gmd:hierarchyLevel><gmd:MD_ScopeCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#MD_ScopeCode" codeListValue="dataset">dataset</gmd:MD_ScopeCode></gmd:hierarchyLevel>
<gmd:contact>
<gmd:CI_ResponsibleParty>
<gmd:individualName><gco:CharacterString>SKUPINSKI Grzegorz</gco:CharacterString></gmd:individualName>
<gmd:organisationName><gco:CharacterString>Laboratoire Image Ville Environnement - URL 7230, UDS-CNRS</gco:CharacterString></gmd:organisationName>
<gmd:positionName><gco:CharacterString>Ing&#233;nieur d'&#233;tudes</gco:CharacterString></gmd:positionName>
<gmd:contactInfo><gmd:CI_Contact>
<gmd:phone><gmd:CI_Telephone><gmd:voice><gco:CharacterString>03 68 85 09 53</gco:CharacterString></gmd:voice></gmd:CI_Telephone></gmd:phone>
<gmd:address><gmd:CI_Address>
<gmd:deliveryPoint><gco:CharacterString>3 rue de l'Argonne</gco:CharacterString></gmd:deliveryPoint>
<gmd:city><gco:CharacterString>Strasbourg</gco:CharacterString></gmd:city>
<gmd:postalCode><gco:CharacterString>67083</gco:CharacterString></gmd:postalCode>
<gmd:electronicMailAddress><gco:CharacterString>grzegorz.skupinski@live-cnrs.unistra.fr</gco:CharacterString></gmd:electronicMailAddress>
</gmd:CI_Address></gmd:address>
</gmd:CI_Contact></gmd:contactInfo>
<gmd:role><gmd:CI_RoleCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#CI_RoleCode" codeListValue="principalInvestigator">principalInvestigator</gmd:CI_RoleCode></gmd:role>
</gmd:CI_ResponsibleParty>
</gmd:contact>
<gmd:dateStamp><gco:Date>2012-07-18</gco:Date></gmd:dateStamp>
<gmd:metadataStandardName><gco:CharacterString>ISO 19115/19139</gco:CharacterString></gmd:metadataStandardName>
<gmd:metadataStandardVersion><gco:CharacterString>Cor 1:2006</gco:CharacterString></gmd:metadataStandardVersion>
<gmd:referenceSystemInfo><gmd:MD_ReferenceSystem>
<gmd:referenceSystemIdentifier><gmd:RS_Identifier>
<gmd:code><gco:CharacterString>WGS84 &#8211; UTM Zone 32N (EPSG:32632)</gco:CharacterString></gmd:code>
</gmd:RS_Identifier></gmd:referenceSystemIdentifier>
</gmd:MD_ReferenceSystem></gmd:referenceSystemInfo>
<gmd:identificationInfo><gmd:MD_DataIdentification>
<gmd:citation><gmd:CI_Citation>
<gmd:title><gco:CharacterString>Image satellite hyperspectrale CASI - 2005- Strasbourg</gco:CharacterString></gmd:title>
<gmd:date><gmd:CI_Date>
<gmd:date><gco:Date>2005-09-21</gco:Date></gmd:date>
<gmd:dateType><gmd:CI_DateTypeCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#CI_DateTypeCode" codeListValue="creation">creation</gmd:CI_DateTypeCode></gmd:dateType>
</gmd:CI_Date></gmd:date>
<gmd:identifier><gmd:RS_Identifier>
<gmd:code><gco:CharacterString>FR-130005457-20050921_CASI_HS_2m_Stras_UTM_P2</gco:CharacterString></gmd:code>
<gmd:codeSpace><gco:CharacterString>MD_URI</gco:CharacterString></gmd:codeSpace>
</gmd:RS_Identifier></gmd:identifier>
</gmd:CI_Citation></gmd:citation>
<gmd:abstract><gco:CharacterString>L'image satelite CASI est une mosa&#238;que d'images num&#233;riques hyperspectrales produite par la soci&#233;t&#233; ActiMar. 
Elle resulte d'une prise de vue a&#233;rienne datant de 21 septembre 2005.

Les caract&#233;ristiques principales des donn&#233;es acquises sont les suivantes : surface : 143 km&#178; ; r&#233;solution spatiale : 2 m&#232;tres ; gamme spectrale : 420 &#8211; 960 nm ; configuration spectrale : 32 bandes spectrales de r&#233;solution FWHM comprise entre 11,4 et 11,8 nm; donn&#233;es calibr&#233;es en r&#233;flectance apparente au sol, corrig&#233;es g&#233;om&#233;triquement (pr&#233;cision +/- 2 m&#232;tres), g&#233;orof&#233;renc&#233;es et mosa&#239;qu&#233;es.</gco:CharacterString></gmd:abstract>
<gmd:pointOfContact>
<gmd:CI_ResponsibleParty>
<gmd:individualName><gco:CharacterString>SKUPINSKI Grzegorz</gco:CharacterString></gmd:individualName>
<gmd:organisationName><gco:CharacterString>Laboratoire Image Ville Environnement - URL 7230, UDS-CNRS</gco:CharacterString></gmd:organisationName>
<gmd:positionName><gco:CharacterString>Ing&#233;nieur d'&#233;tudes</gco:CharacterString></gmd:positionName>
<gmd:contactInfo><gmd:CI_Contact>
<gmd:phone><gmd:CI_Telephone><gmd:voice><gco:CharacterString>03 68 85 09 53</gco:CharacterString></gmd:voice></gmd:CI_Telephone></gmd:phone>
<gmd:address><gmd:CI_Address>
<gmd:deliveryPoint><gco:CharacterString>3 rue de l'Argonne</gco:CharacterString></gmd:deliveryPoint>
<gmd:city><gco:CharacterString>Strasbourg</gco:CharacterString></gmd:city>
<gmd:postalCode><gco:CharacterString>67083</gco:CharacterString></gmd:postalCode>
<gmd:electronicMailAddress><gco:CharacterString>grzegorz.skupinski@live-cnrs.unistra.fr</gco:CharacterString></gmd:electronicMailAddress>
</gmd:CI_Address></gmd:address>
</gmd:CI_Contact></gmd:contactInfo>
<gmd:role><gmd:CI_RoleCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#CI_RoleCode" codeListValue="principalInvestigator">principalInvestigator</gmd:CI_RoleCode></gmd:role>
</gmd:CI_ResponsibleParty>
</gmd:pointOfContact>
<gmd:resourceMaintenance>
<gmd:MD_MaintenanceInformation>
<gmd:maintenanceAndUpdateFrequency>
<gmd:MD_MaintenanceFrequencyCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#MD_MaintenanceFrequencyCode" codeListValue="notPlanned">notPlanned</gmd:MD_MaintenanceFrequencyCode>
</gmd:maintenanceAndUpdateFrequency>
</gmd:MD_MaintenanceInformation>
</gmd:resourceMaintenance>
<gmd:descriptiveKeywords><gmd:MD_Keywords>
<gmd:keyword><gco:CharacterString>Strasbourg (67482)</gco:CharacterString></gmd:keyword>
<gmd:thesaurusName><gmd:CI_Citation>
<gmd:title><gco:CharacterString>Localisation</gco:CharacterString></gmd:title>
<gmd:date><gmd:CI_Date>
<gmd:date><gco:Date>2011-03-22</gco:Date></gmd:date>
<gmd:dateType><gmd:CI_DateTypeCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#CI_DateTypeCode" codeListValue="creation">creation</gmd:CI_DateTypeCode></gmd:dateType>
</gmd:CI_Date></gmd:date>
<gmd:date><gmd:CI_Date>
<gmd:date><gco:Date>2011-03-22</gco:Date></gmd:date>
<gmd:dateType><gmd:CI_DateTypeCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#CI_DateTypeCode" codeListValue="revision">revision</gmd:CI_DateTypeCode></gmd:dateType>
</gmd:CI_Date></gmd:date>
<gmd:date><gmd:CI_Date>
<gmd:date><gco:Date>2011-03-22</gco:Date></gmd:date>
<gmd:dateType><gmd:CI_DateTypeCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#CI_DateTypeCode" codeListValue="publication">publication</gmd:CI_DateTypeCode></gmd:dateType>
</gmd:CI_Date></gmd:date>
</gmd:CI_Citation></gmd:thesaurusName>
</gmd:MD_Keywords></gmd:descriptiveKeywords>
<gmd:descriptiveKeywords><gmd:MD_Keywords>
<gmd:keyword><gco:CharacterString>Environnement</gco:CharacterString></gmd:keyword>
<gmd:thesaurusName><gmd:CI_Citation>
<gmd:title><gco:CharacterString>CTNET</gco:CharacterString></gmd:title>
<gmd:date><gmd:CI_Date>
<gmd:date><gco:Date>2001-02-02</gco:Date></gmd:date>
<gmd:dateType><gmd:CI_DateTypeCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#CI_DateTypeCode" codeListValue="creation">creation</gmd:CI_DateTypeCode></gmd:dateType>
</gmd:CI_Date></gmd:date>
<gmd:date><gmd:CI_Date>
<gmd:date><gco:Date>2001-02-03</gco:Date></gmd:date>
<gmd:dateType><gmd:CI_DateTypeCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#CI_DateTypeCode" codeListValue="revision">revision</gmd:CI_DateTypeCode></gmd:dateType>
</gmd:CI_Date></gmd:date>
<gmd:date><gmd:CI_Date>
<gmd:date><gco:Date>2001-02-02</gco:Date></gmd:date>
<gmd:dateType><gmd:CI_DateTypeCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#CI_DateTypeCode" codeListValue="publication">publication</gmd:CI_DateTypeCode></gmd:dateType>
</gmd:CI_Date></gmd:date>
</gmd:CI_Citation></gmd:thesaurusName>
</gmd:MD_Keywords></gmd:descriptiveKeywords>
<gmd:descriptiveKeywords><gmd:MD_Keywords>
<gmd:keyword><gco:CharacterString>T&#233;l&#233;d&#233;tection</gco:CharacterString></gmd:keyword>
<gmd:thesaurusName><gmd:CI_Citation>
<gmd:title><gco:CharacterString>GEMET</gco:CharacterString></gmd:title>
<gmd:date><gmd:CI_Date>
<gmd:date><gco:Date>2001-03-01</gco:Date></gmd:date>
<gmd:dateType><gmd:CI_DateTypeCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#CI_DateTypeCode" codeListValue="creation">creation</gmd:CI_DateTypeCode></gmd:dateType>
</gmd:CI_Date></gmd:date>
<gmd:date><gmd:CI_Date>
<gmd:date><gco:Date>2001-03-03</gco:Date></gmd:date>
<gmd:dateType><gmd:CI_DateTypeCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#CI_DateTypeCode" codeListValue="revision">revision</gmd:CI_DateTypeCode></gmd:dateType>
</gmd:CI_Date></gmd:date>
<gmd:date><gmd:CI_Date>
<gmd:date><gco:Date>2001-03-03</gco:Date></gmd:date>
<gmd:dateType><gmd:CI_DateTypeCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#CI_DateTypeCode" codeListValue="publication">publication</gmd:CI_DateTypeCode></gmd:dateType>
</gmd:CI_Date></gmd:date>
</gmd:CI_Citation></gmd:thesaurusName>
</gmd:MD_Keywords></gmd:descriptiveKeywords>
<gmd:descriptiveKeywords><gmd:MD_Keywords>
<gmd:keyword><gco:CharacterString>G&#233;ographie</gco:CharacterString></gmd:keyword>
<gmd:thesaurusName><gmd:CI_Citation>
<gmd:title><gco:CharacterString>GEMET</gco:CharacterString></gmd:title>
<gmd:date><gmd:CI_Date>
<gmd:date><gco:Date>2001-03-01</gco:Date></gmd:date>
<gmd:dateType><gmd:CI_DateTypeCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#CI_DateTypeCode" codeListValue="creation">creation</gmd:CI_DateTypeCode></gmd:dateType>
</gmd:CI_Date></gmd:date>
<gmd:date><gmd:CI_Date>
<gmd:date><gco:Date>2001-03-03</gco:Date></gmd:date>
<gmd:dateType><gmd:CI_DateTypeCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#CI_DateTypeCode" codeListValue="revision">revision</gmd:CI_DateTypeCode></gmd:dateType>
</gmd:CI_Date></gmd:date>
<gmd:date><gmd:CI_Date>
<gmd:date><gco:Date>2001-03-03</gco:Date></gmd:date>
<gmd:dateType><gmd:CI_DateTypeCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#CI_DateTypeCode" codeListValue="publication">publication</gmd:CI_DateTypeCode></gmd:dateType>
</gmd:CI_Date></gmd:date>
</gmd:CI_Citation></gmd:thesaurusName>
</gmd:MD_Keywords></gmd:descriptiveKeywords>
<gmd:descriptiveKeywords><gmd:MD_Keywords>
<gmd:keyword><gco:CharacterString>Orthoimagery</gco:CharacterString></gmd:keyword>
<gmd:thesaurusName><gmd:CI_Citation>
<gmd:title><gco:CharacterString>GEMET - INSPIRE themes, version 1.0</gco:CharacterString></gmd:title>
<gmd:date><gmd:CI_Date>
<gmd:date><gco:Date>2008-06-01</gco:Date></gmd:date>
<gmd:dateType><gmd:CI_DateTypeCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#CI_DateTypeCode" codeListValue="publication">publication</gmd:CI_DateTypeCode></gmd:dateType>
</gmd:CI_Date></gmd:date>
</gmd:CI_Citation></gmd:thesaurusName>
</gmd:MD_Keywords></gmd:descriptiveKeywords>
<gmd:resourceConstraints><gmd:MD_Constraints>
<gmd:useLimitation><gco:CharacterString>Donn&#233;es disponibles apres la signature de l'acte d'engagement</gco:CharacterString></gmd:useLimitation>
</gmd:MD_Constraints></gmd:resourceConstraints>
<gmd:resourceConstraints><gmd:MD_Constraints>
<gmd:useLimitation><gco:CharacterString>Mention obligatoire sur tout support de diffusion : Source : CASI 2005 - LIVE</gco:CharacterString></gmd:useLimitation>
</gmd:MD_Constraints></gmd:resourceConstraints>
<gmd:resourceConstraints><gmd:MD_LegalConstraints>
<gmd:accessConstraints>
<gmd:MD_RestrictionCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#MD_RestrictionCode" codeListValue="intellectualPropertyRights">intellectualPropertyRights</gmd:MD_RestrictionCode>
</gmd:accessConstraints>
<gmd:accessConstraints>
<gmd:MD_RestrictionCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#MD_RestrictionCode" codeListValue="otherRestrictions">otherRestrictions</gmd:MD_RestrictionCode>
</gmd:accessConstraints>
<gmd:otherConstraints><gco:CharacterString>Pas de restriction d'acc&#232;s selon INSPIRE</gco:CharacterString></gmd:otherConstraints>
</gmd:MD_LegalConstraints></gmd:resourceConstraints>
<gmd:resourceConstraints><gmd:MD_SecurityConstraints><gmd:classification>
<gmd:MD_ClassificationCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#MD_ClassificationCode" codeListValue="unclassified">unclassified</gmd:MD_ClassificationCode>
</gmd:classification></gmd:MD_SecurityConstraints></gmd:resourceConstraints>
<gmd:spatialRepresentationType>
<gmd:MD_SpatialRepresentationTypeCode codeList="http://www.isotc211.org/2005/resources/codeList.xml#MD_SpatialRepresentationTypeCode" codeListValue="grid">grid</gmd:MD_SpatialRepresentationTypeCode>
</gmd:spatialRepresentationType>
<gmd:spatialResolution><gmd:MD_Resolution>
<gmd:distance><gco:Distance uom="http://standards.iso.org/ittf/PublicityAvailableStandards/ISO_19139_Schemas/resources.uom/ML_gmxUom.xml#m">2</gco:Distance></gmd:distance>
</gmd:MD_Resolution></gmd:spatialResolution>
<gmd:language>
<gmd:LanguageCode codeList="http://www.loc.gov/standards/iso639-2/" codeListValue="fre">fre</gmd:LanguageCode>
</gmd:language>
<gmd:characterSet><gmd:MD_CharacterSetCode codeList="http://www.isotc211.org/2005/resources/codeList.xml#MD_CharacterSetCode" codeListValue="utf8">utf8</gmd:MD_CharacterSetCode></gmd:characterSet>
<gmd:topicCategory><gmd:MD_TopicCategoryCode>environment</gmd:MD_TopicCategoryCode></gmd:topicCategory>
<gmd:extent><gmd:EX_Extent>
<gmd:description><gco:CharacterString /></gmd:description>
<gmd:geographicElement><gmd:EX_GeographicBoundingBox>
<gmd:westBoundLongitude><gco:Decimal>7.65</gco:Decimal></gmd:westBoundLongitude>
<gmd:eastBoundLongitude><gco:Decimal>7.83</gco:Decimal></gmd:eastBoundLongitude>
<gmd:southBoundLatitude><gco:Decimal>48.51</gco:Decimal></gmd:southBoundLatitude>
<gmd:northBoundLatitude><gco:Decimal>48.64</gco:Decimal></gmd:northBoundLatitude>
</gmd:EX_GeographicBoundingBox></gmd:geographicElement>
</gmd:EX_Extent></gmd:extent>
</gmd:MD_DataIdentification></gmd:identificationInfo>
<gmd:distributionInfo><gmd:MD_Distribution>
<gmd:distributionFormat><gmd:MD_Format>
<gmd:name><gco:CharacterString>TIFF</gco:CharacterString></gmd:name>
<gmd:version><gco:CharacterString>6.0</gco:CharacterString></gmd:version>
<gmd:specification><gco:CharacterString /></gmd:specification>
</gmd:MD_Format></gmd:distributionFormat>
<gmd:transferOptions><gmd:MD_DigitalTransferOptions>
</gmd:MD_DigitalTransferOptions></gmd:transferOptions>
</gmd:MD_Distribution></gmd:distributionInfo>
<gmd:dataQualityInfo><gmd:DQ_DataQuality>
<gmd:scope><gmd:DQ_Scope>
<gmd:level><gmd:MD_ScopeCode codeList="http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/Codelist/ML_gmxCodelists.xml#MD_ScopeCode" codeListValue="dataset">dataset</gmd:MD_ScopeCode></gmd:level>
</gmd:DQ_Scope></gmd:scope>
<gmd:lineage><gmd:LI_Lineage>
<gmd:statement><gco:CharacterString>Les mesures a&#233;roport&#233;es ont &#233;t&#233; r&#233;alis&#233;es &#224; l&#8217;aide d&#8217;un capteur de type CASI-2 fabriqu&#233; par la soci&#233;t&#233; ITRES embarqu&#233; sur plate-forme a&#233;roport&#233;e de type Piper Seneca II PA 34. 
Les caract&#233;ristiques principales des donn&#233;es acquises sont les suivantes : surface : 143 km&#178; ; r&#233;solution spatiale : 2 m&#232;tres ; gamme spectrale : 420 &#8211; 960 nm ; configuration spectrale : 32 bandes spectrales de r&#233;solution FWHM comprise entre 11,4 et 11,8 nm; donn&#233;es calibr&#233;es en r&#233;flectance apparente au sol, corrig&#233;es g&#233;om&#233;triquement (pr&#233;cision +/- 2 m&#232;tres), g&#233;orof&#233;renc&#233;es et mosa&#239;qu&#233;es.
Les mesures spectroradiom&#233;triques de terrain ont &#233;t&#233; r&#233;alis&#233;es &#224; l&#8217;aide d&#8217;un capteur de type RAMSES-ARC fabriqu&#233; par la soci&#233;t&#233; TriOS. Le premier ensemble de donn&#233;es spectroradiom&#233;triques de terrain est acquis sur cibles invariantes permettant de corriger les donn&#233;es CASI en r&#233;flectance apparente au sol. Le second ensemble de donn&#233;es est acquis sur cibles th&#233;matiques utiles &#224; l&#8217;analyse ult&#233;rieure des donn&#233;es CASI.
Traitement des donn&#233;es CASI
Les 18 lignes de vol ont &#233;t&#233; mosaiqu&#233;es sous ENVI pour obtenir une seule image de l&#8217;ensemble de la zone couverte en valeurs de luminance.
L&#8217;image CASI-2 calibr&#233;e en luminance a ensuite &#233;t&#233; corrig&#233;e en r&#233;flectance apparente au sol par la m&#233;thode de la ligne empirique :
- Des cibles de r&#233;f&#233;rence invariantes sombres (r&#233;flectance faible sur toute la gamme spectrale, ex : asphalte, parking, etc&#8230;) sont choisies sur la zone &#224; couvrir. Leurs spectres de r&#233;flectance sont mesur&#233;s au sol et r&#233;&#233;chantillonn&#233;s &#224; la configuration spectrale du CASI,
- Des cibles de r&#233;f&#233;rence invariantes claires (r&#233;flectance forte sur toute la gamme spectrale, ex : sable, b&#233;ton clair, etc&#8230;) sont choisies sur la zone &#224; couvrir. Leurs spectres de r&#233;flectance sont mesur&#233;s et r&#233;&#233;chantillonn&#233;s &#224; la configuration spectrale de l&#8217;image CASI,
- Les zones de r&#233;f&#233;rence sont extraites de l&#8217;image CASI,
- La r&#233;gression lin&#233;aire entre valeurs de luminance extraites des images CASI et valeurs de r&#233;flectance acquises au sol sur les cibles de r&#233;f&#233;rence est calcul&#233;e pour chacune des bandes spectrales de l&#8217;image CASI,
- Pour une longueur d&#8217;onde donn&#233;e, les 2 coefficients de la droite de r&#233;gression pr&#233;d&#233;termin&#233;s sont appliqu&#233;s &#224; l&#8217;ensemble de l&#8217;image CASI pour obtenir une image en valeur de r&#233;flectance,
- Cette op&#233;ration est r&#233;it&#233;r&#233;e pour l&#8217;ensemble des bandes spectrales de l&#8217;image CASI.
Cette m&#233;thode prend l&#8217;hypoth&#232;se de conditions d&#8217;&#233;clairement et d&#8217;atmosph&#232;re constants sur l&#8217;ensemble de la mosa&#239;que, hypoth&#232;se qui s&#8217;est av&#233;r&#233;e r&#233;aliste compte tenu de la faible variation de luminance observ&#233;e au niveau du recouvrement des lignes de vol.
Compte tenu des limites de la m&#233;thode de correction en r&#233;flectance, notamment sur les zones d&#8217;ombres, certains pixels de l&#8217;image corrig&#233;e ont des valeurs de r&#233;flectance n&#233;gatives dans les premi&#232;res bandes spectrales.
Cette limite de validit&#233; du mod&#232;le de correction se caract&#233;rise aussi par des valeurs de r&#233;flectance qui d&#233;passe 1 sur certaines bandes et sur certain pixels isol&#233;s, par exemple au niveau de r&#233;flexions sp&#233;culaires sur des vitres.
D&#8217;autre part l&#8217;image corrig&#233;e en r&#233;flectance a &#233;t&#233; convertie du type &#171; Flottant 32 bits &#187; vers
&#171; Entier sign&#233; 16 bits &#187; apr&#232;s application d&#8217;un facteur multiplicatif de 10000, dans le but de r&#233;duire la taille du fichier.
Par cons&#233;quent les pixels isol&#233;s pour lesquels la valeur flottante de r&#233;flectance sur une bande donn&#233;e d&#233;passe 3.2767, (soit 32767 apr&#232;s application du facteur multiplicatif, c&#8217;est &#224; dire la valeur maximale d&#8217;un entier sign&#233; cod&#233; sur 16 bits), prennent apr&#232;s conversion des valeurs n&#233;gatives de l&#8217;ordre de -32768. Ces pixels sont des cas isol&#233;s sur l&#8217;ensemble de l&#8217;image mosa&#239;qu&#233;e.</gco:CharacterString></gmd:statement>
</gmd:LI_Lineage></gmd:lineage>
</gmd:DQ_DataQuality></gmd:dataQualityInfo>
</gmd:MD_Metadata>