J. David Ballester-Berman

University of Alacant · Physics, Systems Engineering and Signal Theory

The production of wild fish has remained relatively stable in the last two decades, whereas aquaculture organism production has increased to the point where it has exceeded wild catches. In this context, accurate and up-to-date information about the current usage of marine areas for aquaculture is crucial for the planning of marine activities. Howe...

A common assumption in radar remote sensing studies for vegetation is that radar returns originate from a target made up by a set of uniformly distributed isotropic scatterers. Nonetheless, several studies in the literature have noted that orientation effects and heterogeneities have a noticeable impact in backscattering signatures according to the...

This proposal follows on from our previous work, in which we presented teachers' and students' perspectives on self-assessment and peer assessment. These assessment methods were presented as valuable options for competence-based assessment. This second part aims to explore local students' perception of self and peer assessment in active learning en...

The model-free four component (MF4C) PolSAR decomposition by Dey et al. and the Neumann volume model are combined and a parameter retrieval strategy is devised for vegetated scenes. Once the decomposition is applied the contributions of all three canonical scattering mechanisms to the <HH·VV*> correlation are retrieved and, hence, the corresponding...

Given the need to use competency assessment systems, a complex problem arises, especially when applying a metric to transversal competencies is intended. In this context, it is possible to use, among other tools, self and peer assessment, so that the first-person perspective of the students is considered among the criteria to quantify aspects that...

The warming of the Mediterranean Sea surface is currently estimated to have been 0.4°C per decade for the period 1985-2006, and the increase in water temperature may have negatively affected marine aquaculture, e.g. by decreasing productivity. Development of aquaculture without adequate planning can lead to unsustainable economic feasibility due to...

Marine aquaculture takes advantage of marine ecosystem services to produce goods that can be relevant from a food security point of view. However, this activity is subject to multiple stressors as the ones exerted by global climate change. Local stressed conditions due to environmental drivers may be exacerbated by the COVID19 pandemic crisis. In t...

The present paper focuses on a sensitivity analysis of Sentinel-1 backscattering signatures from oil palm canopies cultivated in Gabon, Africa. We employed one Sentinel-1 image per year during the 2015–2021 period creating two separated time series for both the wet and dry seasons. The first images were almost simultaneously acquired to the initial...

This study presents a demonstration of the applicability of machine learning techniques for the retrieval of crop height in corn fields using space-borne PolSAR (Polarimetric Synthetic Aperture Radar) data. Multi-year RADARSAT-2 C-band data acquired over agricultural areas in Canada, covering the whole corn growing period, are exploited. Two popula...

This report revisits the role of the extinction coefficient in radar backscattering-based models for forest monitoring. A review of a number of works dealing with this issue has revealed a diversity of extinction values being unclear its dependence on the sensor frequency and the forest type. In addition, a backscattering model directly derived fro...

This report provides a qualitative analysis on the use of multitemporal maps from Sentinel-1 images for supporting forest deforestation tracking and monoculture plantations dynamics. The emphasis is placed in the potential of the resulting maps as visualization tools for end-users involved in designing conservation programs of natural forest ecosys...

Based on experimental results, this chapter describes applications of SAR polarimetry to extract relevant information on agriculture and wetland scenarios by exploiting differences in the polarimetric signature of different scatterers, crop types and their development stage depending on their physical properties. Concerning agriculture, crop type m...

This article evaluates the effect of the double-bounce (DB) decorrelation term that appears in single-pass bistatic acquisitions, as in the TanDEM-X system, on the inversion of scene parameters by means of polarimetric SAR interferometry (PolInSAR). The retrieval of all scene parameters involved in the Random Volume over Ground (RVoG) model (i.e.,...

The performance of model-based decomposition approaches rooted in the Freeman-Durden concept is an active research line in PolSAR field according to the considerable attention it has deserved along the last twenty years. Certainly, most of subsequent proposals have been driven by the only objective of getting a better qualitative balance among scat...

The standard single-pass bistatic acquisition mode of the TanDEM-X sensor entails an extra decorrelation term when the radar response from the ground is dominated by the double-bounce interaction between stems or trunks and ground. This term is usually overlooked in studies using Polarimetric SAR Interferometry (PolInSAR). In this work, we study th...

The inversion of the well-known Random Volume over Ground (RVoG) model is employed for the estimation of physical parameters of scenes with vegetation by exploiting polarimetric SAR Interferometry (PolInSAR) data. Data gathered by the TanDEM-X satellite formation are characterised by a single-pass bistatic configuration, where one satellite is tran...

In bistatic acquisitions the presence of a double-bounce contribution at the ground affects the interferometric coherence with a decorrelation factor which is usually overlooked in studies employing polarimetric SAR interferometry. The standard acquisition mode of TanDEM-X is bistatic, so the influence of this contribution in the estimation of scen...

In recent years the FAO Fisheries and Aquaculture Department has been carrying out strategies and policies aimed at improving the regulatory laws on aquaculture and fisheries activities for increasing both the management efficiency and environmental protection associated to this task. In this field, the role of temporal and geo-spatial analysis of...

The interferometric coherence is a measure of the correlation between two SAR images and constitutes a commonly used estimator of the phase quality. Its estimation requires a spatial average within a 2-D window, usually named as multilook. The multilook processing allows reducing noise at the expenses of a resolution loss. In this letter, we analyz...

Results, radar measurements and the script for both reading the data and reproducing the outputs can be downloaded at: https://personal.ua.es/en/davidb/time-frequency-analysis-of-radar-signals-from-vegetation-scattering.html

In this theoretical study we propose to use the complex frequency correlation function (FCF) of radar backscatter developed by Sarabandi and Nashashibi to separate scattering mechanisms in PolSAR data. The idea is based on the possibility of filtering out the volume contribution from the ground ones according to their extremely different decorrelat...

This paper investigates the potentials and limitations of a simple dual-baseline PolInSAR (DBPI) method for forest height inversion. This DBPI method follows the classical three-stage inversion method’s idea used in single baseline PolInSAR (SBPI) inversion, but it avoids the assumption of the smallest ground-to-volume amplitude ratio (GVR) by empl...

Soil moisture estimations by using a recently proposed methodology for general polarimetric decompositions (see reference below) are presented. The test site is located in Riau Province, Sumatra, where primary rainforests are being irreversibly substituted by monoculture-based industrial plantations. These are preliminary results and the retrieved...

The code generates the results from the article: Xie, Q.; Ballester-Berman, J. David; Lopez-Sanchez, Juan M.; Zhu, J.; Wang, C. Quantitative Analysis of Polarimetric Model-Based Decomposition Methods. Remote Sensing, 2016, 8, 977; doi:10.3390/rs8120977 See the script named as ’Demo.m’ for an example on how to run the code. The Copyright is owned by...

Recently, a general polarimetric model-based decomposition framework was proposed by Chen et al., which addresses several well-known limitations in previous decomposition methods and implements a simultaneous full-parameter inversion by using complete polarimetric information. However, it only employs four typical models to characterize the volume...

Recently, a general polarimetric model-based decomposition framework was proposed by Chen et al., which addresses several well-known limitations in previous decomposition methods and implements a simultaneous full-parameter inversion by using complete polarimetric information. However, it only employs four typical models to characterize the volume...

In this paper, we analyze the robustness of the parameter inversion provided by general polarimetric model-based decomposition methods from the perspective of a quantitative application. The general model and algorithm we have studied is the method proposed recently by Chen et al., which makes use of the complete polarimetric information and outper...

In this paper, we present a simple algorithm for assessing the validity of the RVoG model for PolInSAR-based inversion techniques. This approach makes use of two important features characterizing a homogeneous random volume over a ground surface, i.e., the independence on polarization states of wave propagation through the volume and the structure...

The coherent nature of the acquisition by TerraSAR-X of both copolar channels (HH and VV) enables the generation of many different polarimetric observables with physical interpretation, as have recently been used for monitoring rice fields. In this letter, the influence of incidence angle upon these polarimetric observables is analyzed by comparing...

A set of ten RADARSAT-2 images acquired in fully polarimetric mode over a test site with rice fields in Seville, Spain, has been analyzed to extract the main features of the C-band radar backscatter as a function of rice phenology. After observing the evolutions versus phenology of different polarimetric observables and explaining their behavior in...

In this paper we propose a two-component polarimetric model for soil moisture estimation on vineyards suited for C-band radar data. According to a polarimetric analysis carried out here, this scenario is made up of one dominant direct return from the soil and a multiple scattering component accounting for disturbing and non- modeled signal °uctuati...

The feasibility of retrieving the phenological stage of rice fields at a particular date by employing coherent copolar dual-pol X-band radar images acquired by the TerraSAR-X sensor has been investigated in this paper. A set of polarimetric observables that can be derived from this data type has been studied by using a time series of images gathere...

The use of polarimetric interferometry to monitor vegetation covers, assuming simple models like the RVoG, is influenced by the acquisition mode of the interferometer: single-tx or alternate-tx. Theoretical expressions obtained for the single-tx mode have not been validated with real data yet. In this work we address this validation by employing a...

A complete polarimetric study on C-band RADARSAT-2 data over vineyards in Spain has been performed in order to explore the sensitivity to growth stages. This analysis suggests that scattering response of vines can be approximated as a two-component scenario comprising a strong return from soil and a weak depolarized return due to grapes and leaves....

This paper aims to examine the sensitivity of C-band RADARSAT-2 polarimetric data to the phenology of vineyards and the potential of this technology to monitor variation in grapevine biomass. The analysis conducted indicates that the cross-polar channel exhibits a signature as a function of phenology and particularly from the phenological stage whe...

A set of three quad-pol images acquired at the L-band in interferometric repeat-pass mode by the German Aerospace Center (DLR) with the Experimental SAR (E-SAR) system, in parallel with the AgriSAR2006 campaign, has been used to provide, for the first time with airborne data, a demonstration of the retrieval of vegetation height from agricultural c...

An example of the potential of hybrid-polarity architecture parameters for agricultural monitoring is presented in this letter. Time series of such descriptors have been generated from quad-polarization radar airborne measurements at the L-band acquired during the AgriSAR 2006 campaign. An assessment on the sensitivity of these observables for moni...

This work presents a study about the evolution of the radar response of rice fields at X-band as a function of their phenology, by using three time series of coherent HHVV dual-pol X-band radar images acquired by the TerraSAR-X sensor at different incidence angles during a whole cultivation season. After analyzing a wide set of polarimetric observa...

This work will present a study about the capabilities of PolInSAR for agriculture applications with TanDEM-X data, since this sensor will acquire for the first time single-pass PolInSAR data from space. The use of single-pass acquisitions is mandatory for such application due to the rapid growth of crops. In addition, X-band provides a good trade-o...

Time series of dual-pol TerraSAR-X images have been acquired during the whole cultivation period over a rice site in Spain. The objective of this paper is to investigate the coherent co-polarized behavior of rice plants during the growing stages and to explore their information content for rice monitoring at high frequencies recently available thro...

Complex interferometric coherence expressions for the homogeneous (random or oriented) volume-over-ground model are originally derived in a simplified way by neglecting one of the two possible contributions of the ground response: direct return from the ground surface or double-bounce interaction with stems or trunks. The influence of these depends...

A generic electromagnetic model for agriculture scenes has been extended and adapted to simulate the X-band SAR response of rice fields during their whole phenological cycle. Simulations of different polarimetric observables have been useful for interpreting time series of dual-pol TerraSAR-X images acquired during 2008 and 2009 over rice fields in...

Quad-pol measurements at L-band acquired during the AGRISAR¿06 campaign have been used in order to compute time series of entropy, alpha angle and anisotropy from an agricultural area with a simultaneous dedicated ground-data acquisition. The study has been focused on winter wheat, maize and rape crops, and the biophysical parameters considered we...

In this paper the formulation of the Freeman-Durden decomposition has been extended to PolInSAR data sets. The procedure assumes that the interferometric cross-correlation for the linear basis can be decomposed into the three mechanisms considered by the Freeman-Durden approach (i.e. direct, double-bounce and volume scattering mechanisms) even thou...

In this paper, the Freeman-Durden polarimetric decomposition concept is adapted to polarimetric SAR interferometry (PolInSAR) data. The covariance matrix obtained from PolInSAR observations is decomposed into the three scattering mechanisms matrices proposed by Freeman and Durden for polarimetric SAR (PolSAR) data. The objective is to describe each...

3-D high-resolution radar images have been produced for a mature rice crop sample by using wide-band fully polari-metric data collected at the EMSL, JRC-Ispra (Italy). These images have been compared with the 1D vertical density profiles produced by the Polarization Coherence Tomography technique on the same rice sample. In order to obtain a 1D ver...

This paper is aimed to define the main specifications and system requirements of a future spaceborne synthetic aperture radar (SAR) mission with polarimetric and interferometric capabilities, to be applied in agriculture monitoring. Firstly, a previous discussion concerning the applications of remote sensing to agriculture and the requirements dema...

Three time series of dual-pol TerraSAR-X images have been acquired during the whole cultivation period for a rice site in Spain. Among different observations, the backscattering at HH and VV channels, and the HH/VV ratio at 30 degrees incidence has shown a temporal signature with a clear correlation with the development of plants during the vegetat...

In this work we have applied the polarization coherence tomography (PCT) to indoor data acquired on a rice sample. Different baselines, frequency bands and polarimetric channels have been used in order to analyze the potential of this technique for retrieving information about the vertical structure of such a specific crop and, additionally, these...

This work presents a phase unwrapping (PU) algorithm for SAR interferometry based on a particle filter (PF). This PU algorithm performs simultaneously noise filtering and phase unwrapping. The formulation of this technique provides independence from noise statistics and is not constrained by the non linearity of the problem. Results show a signific...

The complex interferometric coherence expressions for the RVoG and the OVoG models were originally derived in a simplified way by neglecting one of the two possible contributions of the ground response: direct return from the ground surface or double-bounce interaction with the stems or trunks. When applied to agriculture, the influence of these co...

Application of polarimetric synthetic aperture radar interferometry to the retrieval of geophysical parameters from vegetated scenes is based on simple direct models of such scenes. The first part of this paper presents an analysis of the correspondence between these simple models, namely, the random volume over ground and the oriented volume over...

The formulation of the complex interferometric coherence for the oriented volume over ground model (OVoG) has been recently proposed for the case of dominant double-bounce mechanism from the ground when the interferometer is operated in single-transmit (bistatic) mode. This paper analyzes the two contributions to the total coherence function: the v...

The formulation of the polarimetric interferometric coherences derived by simple homogeneous-volume-over-ground models is revisited for the case of ground returns dominated by the double-bounce terms. The differences between single-transmit (single-tx) and alternate-transmit modes of the interferometer are analyzed by inspecting the positions of th...

Mathematical expressions for the interferometric coherence of homogeneous-volume-over-ground models (RVoG and OVoG) for the case of dominant specular scattering and considering a single-tx interferometer are derived. The analysis of the positions of the coherences on the complex plane, as a function of the polarization channel, yields important dif...

The oriented volume over ground (OVoG) is a simple model applied to the retrieval of biophysical parameters of agricultural crops from polarimetric SAR interferometry data. To date, only a part of the model parameters has been retrieved because the inversion of the model is indeterminate when a single-baseline interferometer is used. In this work,...

A study of the wide-band polarimetric backscatter of maize plants, measured in laboratory conditions, is presented. The backscatter slant-range profiles in both linear (H-V) and Pauli basis manifest a higher extinction coefficient in the vertical channel due to the dominant vertical orientation of the structure of corn plants. The difference betwee...

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An existing two-layer model for forest height estimation is adapted for agricultural crops in order to develop a retrieval algorithm based on polarimetric synthetic aperture radar interferometry. This new inversion scheme is specifically tailored for vertically oriented agricultural crops, with extinction coefficients dependent on the wave polariza...

A modification of the well-known random volume over ground (RVoG) model [1] has been recently proposed to accommodate its working principle to the case of oriented vegetation volumes, which are very common in agricultural crops [2]. The modified model, also called OVoG, can be applied to the retrieval of vegetation height and ground topogra-phy of...

An exhaustive analysis of the electromagnetic response from a maize sample, measured in laboratory conditions, is presented. Fully polarimetric wide-band radar data have been collected in order to compute backscatter profiles (i.e. 1D images) as a function of height. First results consist on backscatter images expressed in Pauli and linear basis. T...

Polarimetric SAR interferometry (Pol-InSAR) has been applied successfully to retrieve biophysical parameters from forest areas. This technique employs a scene model composed of a random volume over the ground. However, that model is based on the assumption that the wave propagation through the vegetation canopy is independent of polarization, which...

A coherent electromagnetic model developed for estimating the radar backscatter from rice crops is presented. This model is based on the first order solution of the polarimetric backscatter response as a function of the sensor parameters and the physical description of the rice plants. This paper presents a comparison between simulations obtained b...

This paper presents a review of the advances and current status of the application of polarimetric SAR interferometry to the retrieval of biophysical parameters of agricultural crops. Since currently there is no system with the required features to apply this technique, we focus our study on the theoretical modeling aspects (both direct and inverse...

Abstract The application of Polarimetric SAR Interferometry (POLINSAR) to the retrieval of parameters from vegetation scenes modelled by the RVoG and the OVoG requires the solution of a highly nonlinear problem. In this paper, some strategies used to solve this problem are described. They are based on a geometrical approach, originally presented fo...