Cláudia de Almeida

Dr. Cláudia de Almeida

National Institute for Space Research - INPE
orcid

Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
15 July 2008 in International Journal of Geographical Information Science
Verified
Journal Article
Closed access
Cláudia de AlmeidaCláudia de Almeida
Cláudia de Almeida
JGJ. M. Gleriani
J. M. Gleriani
ECE. F. Castejon
E. F. Castejon
BSB. S. Soares‐Filho
B. S. Soares‐Filho
Empirical models designed to simulate and predict urban land‐use change in real situations are generally based on the utilization of statistical techniques to compute the land‐use change probabilities. In contrast to these methods, artificial neural networks arise as an alternative to assess such probabilities by means of non‐parametric approaches. This work introduces a simulation experiment on intra‐urban land‐use change in which a supervised back‐propagation neural network has been employed in the parameterization of several biophysical and infrastructure variables considered in the simulation model. The spatial land‐use transition probabilities estimated thereof feed a cellular automaton (CA) simulation model, based on stochastic transition rules. The model has been tested in a medium‐sized town in the Midwest of São Paulo State, Piracicaba. A series of simulation outputs for the case study town in the period 1985–1999 were generated, and statistical validation tests were then conducted for the best results, based on fuzzy similarity measures.

1 September 2003 in Computers, Environment and Urban Systems
Verified
Journal Article
Closed access
Cláudia de AlmeidaCláudia de Almeida
Cláudia de Almeida
MBMichael Batty
Michael Batty
AMAntonio Miguel Vieira Monteiro
Antonio Miguel Vieira Monteiro
GCGilberto Câmara
Gilberto Câmara
BSBritaldo Silveira Soares-Filho
Britaldo Silveira Soares-Filho
CPCássio Lopes Pennachin
Cássio Lopes Pennachin

12 January 2020 in GIScience & Remote Sensing
Verified
Journal Article
Closed access
Camile SotheCamile Sothe
Camile Sothe
Cláudia de AlmeidaCláudia de Almeida
Cláudia de Almeida
Marcos SchimalskiMarcos Schimalski
Marcos Schimalski
LRL. E. C. La Rosa
L. E. C. La Rosa
JCJose David Bermudez Castro
Jose David Bermudez Castro
ATA. M. G. Tommaselli
A. M. G. Tommaselli
The classification of tree species can significantly benefit from high spatial and spectral information acquired by unmanned aerial vehicles (UAVs) associated with advanced classification methods. This study investigated the following topics concerning the classification of 16 tree species in two subtropical forest fragments of Southern Brazil: i) the potential integration of UAV-borne hyperspectral images with 3D information derived from their photogrammetric point cloud (PPC); ii) the performance of two machine learning methods (support vector machine – SVM and random forest – RF) when employing different datasets at a pixel and individual tree crown (ITC) levels; iii) the potential of two methods for dealing with the imbalanced sample set problem: a new weighted SVM (wSVM) approach, which attributes different weights to each sample and class, and a deep learning classifier (convolutional neural network – CNN), associated with a previous step to balance the sample set; and finally, iv) the potential of this last classifier for tree species classification as compared to the above mentioned machine learning methods. Results showed that the inclusion of the PPC features to the hyperspectral data provided a great accuracy increase in tree species classification results when conventional machine learning methods were applied, between 13 and 17% depending on the classifier and the study area characteristics. When using the PPC features and the canopy height model (CHM), associated with the majority vote (MV) rule, the SVM, wSVM and RF classifiers reached accuracies similar to the CNN, which outperformed these classifiers for both areas when considering the pixel-based classifications (overall accuracy of 84.4% in Area 1, and 74.95% in Area 2). The CNN was between 22% and 26% more accurate than the SVM and RF when only the hyperspectral bands were employed. The wSVM provided a slight increase in accuracy not only for some lesser represented classes, but also some major classes in Area 2. While conventional machine learning methods are faster, they demonstrated to be less stable to changes in datasets, depending on prior segmentation and hand-engineered features to reach similar accuracies to those attained by the CNN. To date, CNNs have been barely explored for the classification of tree species, and CNN-based classifications in the literature have not dealt with hyperspectral data specifically focusing on tropical environments. This paper thus presents innovative strategies for classifying tree species in subtropical forest areas at a refined legend level, integrating UAV-borne 2D hyperspectral and 3D photogrammetric data and relying on both deep and conventional machine learning approaches.

13 August 2017 in Remote Sensing
Verified
Journal Article
Open access
PDF file
Camile SotheCamile Sothe
Camile Sothe
Cláudia de AlmeidaCláudia de Almeida
Cláudia de Almeida
Veraldo LiesenbergVeraldo Liesenberg
Veraldo Liesenberg
Marcos SchimalskiMarcos Schimalski
Marcos Schimalski
Studies designed to discriminate different successional forest stages play a strategic role in forest management, forest policy and environmental conservation in tropical environments. The discrimination of different successional forest stages is still a challenge due to the spectral similarity among the concerned classes. Considering this, the objective of this paper was to investigate the performance of Sentinel-2 and Landsat-8 data for discriminating different successional forest stages of a patch located in a subtropical portion of the Atlantic Rain Forest in Southern Brazil with the aid of two machine learning algorithms and relying on the use of spectral reflectance data selected over two seasons and attributes thereof derived. Random Forest (RF) and Support Vector Machine (SVM) were used as classifiers with different subsets of predictor variables (multitemporal spectral reflectance, textural metrics and vegetation indices). All the experiments reached satisfactory results, with Kappa indices varying between 0.9, with Landsat-8 spectral reflectance alone and the SVM algorithm, and 0.98, with Sentinel-2 spectral reflectance alone also associated with the SVM algorithm. The Landsat-8 data had a significant increase in accuracy with the inclusion of other predictor variables in the classification process besides the pure spectral reflectance bands. The classification methods SVM and RF had similar performances in general. As to the RF method, the texture mean of the red-edge and SWIR bands were considered the most important ranked attributes for the classification of Sentinel-2 data, while attributes resulting from multitemporal bands, textural metrics of SWIR bands and vegetation indices were the most important ones in the Landsat-8 data classification.

3 June 2019 in Remote Sensing
Verified
Journal Article
Open access
PDF file
Camile SotheCamile Sothe
Camile Sothe
MDMichele Dalponte
Michele Dalponte
Cláudia de AlmeidaCláudia de Almeida
Cláudia de Almeida
Marcos SchimalskiMarcos Schimalski
Marcos Schimalski
CLCarla Luciane Lima
Carla Luciane Lima
Antonio TommaselliAntonio Tommaselli
Antonio Tommaselli
The use of remote sensing data for tree species classification in tropical forests is still a challenging task, due to their high floristic and spectral diversity. In this sense, novel sensors on board of unmanned aerial vehicle (UAV) platforms are a rapidly evolving technology that provides new possibilities for tropical tree species mapping. Besides the acquisition of high spatial and spectral resolution images, UAV-hyperspectral cameras operating in frame format enable to produce 3D hyperspectral point clouds. This study investigated the use of UAV-acquired hyperspectral images and UAV-photogrammetric point cloud (PPC) for classification of 12 major tree species in a subtropical forest fragment in Southern Brazil. Different datasets containing hyperspectral visible/near-infrared (VNIR) bands, PPC features, canopy height model (CHM), and other features extracted from hyperspectral data (i.e., texture, vegetation indices-VIs, and minimum noise fraction-MNF) were tested using a support vector machine (SVM) classifier. The results showed that the use of VNIR hyperspectral bands alone reached an overall accuracy (OA) of 57% (Kappa index of 0.53). Adding PPC features to the VNIR hyperspectral bands increased the OA by 11%. The best result was achieved combining VNIR bands, PPC features, CHM, and VIs (OA of 72.4% and Kappa index of 0.70). When only the CHM was added to VNIR bands, the OA increased by 4.2%. Among the hyperspectral features, besides all the VNIR bands and the two VIs (NDVI and PSSR), the first four MNF features and the textural mean of 565 and 679 nm spectral bands were pointed out as more important to discriminate the tree species according to Jeffries–Matusita (JM) distance. The SVM method proved to be a good classifier for the tree species recognition task, even in the presence of a high number of classes and a small dataset.

1 February 2005 in International Journal of Remote Sensing
Verified
Journal Article
Closed access
Cláudia de AlmeidaCláudia de Almeida
Cláudia de Almeida
AMAntonio Miguel Vieira Monteiro
Antonio Miguel Vieira Monteiro
GCGilberto Câmara
Gilberto Câmara
BSBritaldo Silveira Soares‐Filho
Britaldo Silveira Soares‐Filho
GCGustavo Coutinho Cerqueira
Gustavo Coutinho Cerqueira
MBMichael Batty
Michael Batty
This paper is concerned with building up methodological guidelines for modelling urban land‐use change through Geographical Information Systems, remote sensing imagery and Bayesian probabilistic methods. A medium‐sized town in the west of São Paulo State, Bauru, was adopted as a case study. Its urban structure was converted into a 100 m×100 m resolution grid and transition probabilities were calculated for each grid cell by means of the ‘weights of evidence’ statistical method and upon the basis of the information related to the technical infrastructure and socio‐economic aspects of the town. The probabilities obtained from there fed a cellular automaton simulation model—DINAMICA—developed by the Centre for Remote Sensing of the Federal University of Minas Gerais (CSR‐UFMG), based on stochastic transition algorithms. Different simulation outputs for the case study town in the period 1979–1988 were generated, and statistical validation tests were then conducted for the best results, employing a multiple resolution fitting procedure. This modelling experiment revealed the plausibility of adopting Bayesian empirical methods based on the available knowledge of technical infrastructure and socio‐economic status to simulate urban land‐use change. It indicates their possible further applicability for generating forecasts of growth trends both for Brazilian cities and cities world‐wide.