Individual tree crown delineation in a highly diverse tropical forest using very high resolution satellite images

Autor(es)

Wagner, Fabien Hubert ; Ferreira, Matheus Pinheiro ; Sanchez, Alber ; Hirye, Mayumi C. M. ; Zortea, Maciel ; Gloor, Emanuel ; Phillips, Oliver L. ; de Souza Filho, Carlos Roberto ; Shimabukuro, Yosio Edemir ; Aragao, Luiz E. O. C.

• Tipo de documento: Artigo Científico
• Fonte: ISPRS JOURNAL OF PHOTOGRAMMETRY AND REMOTE SENSING; v. 145, p. 16-pg., 2018-11-01.

Resumo

Mapping tropical tree species at landscape scales to provide information for ecologists and forest managers is a new challenge for the remote sensing community. For this purpose, detection and delineation of individual tree crowns (ITCs) is a prerequisite. Here, we present a new method of automatic tree crown delineation based only on very high resolution images from WorldView-2 satellite and apply it to a region of the Atlantic rain forest with highly heterogeneous tropical canopy cover - the Santa Genebra forest reserve in Brazil. The method works in successive steps that involve pre-processing, selection of forested pixels, enhancement of borders, detection of pixels in the crown borders, correction of shade in large trees and, finally, segmentation of the tree crowns. Principally, the method uses four techniques: rolling ball algorithm and mathematical morphological operations to enhance the crown borders and ease the extraction of tree crowns; bimodal distribution parameters estimations to identify the shaded pixels in the gaps, borders, and crowns; and focal statistics for the analysis of neighbouring pixels. Crown detection is validated by comparing the delineated ITCs with a sample of ITCs delineated manually by visual interpretation. In addition, to test if the spectra of individual species are conserved in the automatic delineated crowns, we compare the accuracy of species prediction with automatic and manual delineated crowns with known species. We find that our method permits detection of up to 80% of ITCs. The seven species with over 10 crowns identified in the field were mapped with reasonable accuracy (30.5-96%) given that only WorldView-2 bands and texture features were used. Similar classification accuracies were obtained using both automatic and manual delineation, thereby confirming that species' spectral responses are preserved in the automatic method and thus permitting the recognition of species at the landscape scale. Our method might support tropical forest applications, such as mapping species and canopy characteristics at the landscape scale. (AU)

• Processo FAPESP: 16/03397-7 - Ferramentas para gerenciar imagens de satélite em array databases
• Beneficiário: Alber Hamersson Sánchez Ipia
• Modalidade de apoio: Bolsas no Brasil - Programa Capacitação - Treinamento Técnico
• Processo FAPESP: 13/50533-5 - Entendendo as respostas do metabolismo fotossintético a variações climáticas sazonais em florestas tropicais
• Beneficiário: Luiz Eduardo Oliveira e Cruz de Aragão
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 13/11589-5 - Estudo da diversidade química e espectral de espécies arbóreas da floresta atlântica: implicações para o monitoramento por sensoriamento remoto
• Beneficiário: Matheus Pinheiro Ferreira
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 16/17652-9 - Diversidade funcional dos biomas Amazônia, Mata Atlântica e Cerrado nos ambientes intactos e em regeneração por meio de imagens hiperspectrais
• Beneficiário: Fabien Hubert Wagner
• Modalidade de apoio: Bolsas no Brasil - Jovens Pesquisadores
• Processo FAPESP: 16/24977-1 - Mapeamento e extração de atributos químicos de espécies arbóreas da Mata Atlântica por meio de imagens hiperespectrais e modelagem de transferência radiativa
• Beneficiário: Matheus Pinheiro Ferreira
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 15/50484-0 - Diversidade funcional dos biomas Amazônia, Mata Atlântica e Cerrado nos ambientes intactos e em regeneração por meio de imagens hiperspectrais
• Beneficiário: Fabien Hubert Wagner
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores