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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

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

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Wagner, Fabien Hubert [1] ; Ferreira, Matheus Pinheiro [1, 2] ; Sanchez, Alber [1] ; Hirye, Mayumi C. M. [1] ; Zortea, Maciel [3] ; Gloor, Emanuel [4] ; Phillips, Oliver L. [4] ; de Souza Filho, Carlos Roberto [5] ; Shimabukuro, Yosio Edemir [1] ; Aragao, Luiz E. O. C. [1, 6]
Total Authors: 10
[1] Natl Inst Space Res INPE, Remote Sensing Div, BR-12227010 Sao Jose Dos Campos, SP - Brazil
[2] Mil Inst Engn IME, Cartog Engn Sect, Praca Gen Tiburcio 80, BR-22290270 Rio De Janeiro, RJ - Brazil
[3] IBM Res Brazil, Ave Pasteur 138, BR-22290240 Rio De Janeiro, RJ - Brazil
[4] Univ Leeds, Sch Geog, Ecol & Global Change, Leeds LS2 9JT, W Yorkshire - England
[5] Univ Estadual Campinas, Geosci Inst, R Joao Pandia Calogeras 51, BR-13083870 Campinas, SP - Brazil
[6] Univ Exeter, Coll Life & Environm Sci, Exeter EX4 4RJ, Devon - England
Total Affiliations: 6
Document type: Journal article
Web of Science Citations: 9

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)

FAPESP's process: 13/11589-5 - Study of chemical and spectral diversity of Atlantic Forest tree species: implications for remote sensing monitoring
Grantee:Matheus Pinheiro Ferreira
Support type: Scholarships in Brazil - Doctorate
FAPESP's process: 16/03397-7 - Tools for satellite images management in array databases
Grantee:Alber Hamersson Sánchez Ipia
Support type: Scholarships in Brazil - Technical Training Program - Technical Training
FAPESP's process: 13/50533-5 - Understanding the response of photosynthetic metabolism in tropical forests to seasonal climate variations
Grantee:Luiz Eduardo Oliveira e Cruz de Aragão
Support type: Regular Research Grants
FAPESP's process: 15/50484-0 - Functional diversity of intact and regenerating Amazon, Atlantic, and Cerrado systems using hyperspectral imagery
Grantee:Fabien Hubert Wagner
Support type: Research Grants - Young Investigators Grants
FAPESP's process: 16/24977-1 - Measuring and mapping Atlantic Forest canopy foliar traits with hyperspectral images and radiative transfer modeling
Grantee:Matheus Pinheiro Ferreira
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 16/17652-9 - Functional diversity of intact and regenerating Amazon, Atlantic Forest and Cerrado systems using hyperspectral imagery
Grantee:Fabien Hubert Wagner
Support type: Scholarships in Brazil - Young Researchers