https://hdl.handle.net/10481/19801 Fri, 17 Apr 2026 07:05:54 GMT 2026-04-17T07:05:54Z https://hdl.handle.net/10481/77004 Increasing the Lateral Resolution of 3D-GPR Datasets through 2D-FFT Interpolation with Application to a Case Study of the Roman Villa of Horta da Torre (Fronteira, Portugal) Oliveira, Rui Jorge; Teixidó Ullod, Teresa The approach presented in this work uses an interpolation methodology to densify 3D-GPR datasets to sharpen the results obtained in GPR surveys carried out in an archaeological environment. It allows the estimation of missing data from the combined use of mathematical transforms, such as the Fourier and curvelet transforms, and predictive filters. This technique makes it possible to calculate the missing signal simply by meeting two requirements: the data in the frequency domain must be limited in a range of values and must be able to be represented by a distribution of Fourier coefficients (verified conditions). The INT-FFT algorithm uses an open-access routine (Suinterp, Seismic Unix) to interpolate the GPR B-scans based on seismic trace interpolation. This process uses automatic event identification routines by calculating spatial derivatives to identify discontinuities in space by detecting very subtle changes in the signal, thus allowing for more efficient interpolation without artifacts or signal deterioration. We successfully tested the approach using GPR datasets from the Roman villa of Horta da Torre (Fronteira, Portugal). The results showed an increase in the geometric sharpness of the GPR reflectors and did not produce any numerical artifacts. The tests performed to apply the methodology to GPR-3D data allowed for assessing the interpolation efficiency, the level of estimation of missing data, and the level of information lost when we chose to increase the distance between B-scans in the acquisition stage. https://hdl.handle.net/10481/77004 https://hdl.handle.net/10481/68603 GPR Clutter Reflection Noise-Filtering through Singular Value Decomposition in the Bidimensional Spectral Domain Oliveira, Rui Jorge; Teixidó Ullod, Teresa Usually, in ground-penetrating radar (GPR) datasets, the user defines the limits between the useful signal and the noise through standard filtering to isolate the effective signal as much as possible. However, there are true reflections that mask the coherent reflectors that can be considered noise. In archaeological sites these clutter reflections are caused by scattering with origin in subsurface elements (e.g., isolated masonry, ceramic objects, and archaeological collapses). Its elimination is difficult because the wavelet parameters similar to coherent reflections and there is a risk of creating artefacts. In this study, a procedure to filter the clutter reflection noise (CRN) from GPR datasets is presented. The CRN filter is a singular value decomposition-based method (SVD), applied in the 2D spectral domain. This CRN filtering was tested in a dataset obtained from a controlled laboratory environment, to establish a mathematical control of this algorithm. Additionally, it has been applied in a 3D-GPR dataset acquired in the Roman villa of Horta da Torre (Fronteira, Portugal), which is an uncontrolled environment. The results show an increase in the quality of archaeological GPR planimetry that was verified via archaeological excavation. https://hdl.handle.net/10481/68603 https://hdl.handle.net/10481/23534 Prospección magnética y georrádar 3D para delimitación y caracterización de yacimientos arqueológicos: casos de estudio Teixidó Ullod, Teresa; Peña, José Antonio; López Castro, José Luis; Ibáñez Castro, Alejandro; Sierra, Manuel; Ferjaoui, Ahmed En este estudio se describe una metodología de prospección geofísica aplicable a yacimientos arqueológicos de una cierta extensión, normalmente del orden de una ha o superior. Como se verá, dicha metodología va a ser aplicada con diferentes matices a tres casos de estudio, demostrándose cómo el uso de dos métodos de prospección complementarios proporciona una mayor y valiosa información sobre los yacimientos, que compensa y justifica con creces el “relativo” encarecimiento de la prospección geofísica. De los dos métodos complementarios que proponemos, el primero es la prospección magnética porque es de rápida aplicación y permite una primera visión / zonificación del yacimiento. Mientras que el segundo es el rádar del subsuelo 3D (georrádar o GPR); método un poco más lento de adquisición pero de mayor resolución, y que permite detallar mejor las anomalías más notables detectadas por el primer método. I Congreso Internacional "El patrimonio cultural y natural como motor de desarrollo: investigación e innovación", se celebro en la Universidad de Jaén del 26 al 28 de enero de 2011, y se enmarca dentro del Proyecto Campus de Excelencia Internacional en Patromonio Cultural y Natural que está promovido por las diez universidades públicas de Andalucía. https://hdl.handle.net/10481/23534 https://hdl.handle.net/10481/23463 Comparación entre radar del subsuelo de baja frecuencia y sísmica de reflexión de alta resolución para la detección de la seria fosfatada de la cuenca de Sidi Chennane (Marruecos) Teixidó Ullod, Teresa; Kchikach, Azzouz; Peña, José Antonio; Carmona, Enrique; Jaffal, Mohamed; Bouya, Baâdi Devido à importância dos depósitos fosfáticos de Sidi Chennane (Khouribga, Marrocos), a pessoa veio, enquanto explorando com sondagem eletromagnéticos no domínio do tempo (TDEM) e Sondagem Verticais Elétricas(SEV). Ambos tipos de investigação tiveram como objetivo a localização dos corpos estéreis que fican escondidos nas camadas de fosfato; e que são a causa principal de interrupção dos trabalhos de exploração mineira. E, embora para eles foram mostrados como métodos válidos para a localização destes corpos, apresentam a inconveniência que são métodos lentos na aquisição de dados de campo, si se faze conta das demandas de produção do jazigo. Durante dois anos, nosso grupo de investigação está avaliando a aplicação de rádar do subsolo (Ground Penetrating Radar method; GPR) como técnica mais rápida de aquisição de dados e obtendo de resultados. Para isto foi usado uma antena biestática de 40 MHz e o perfil ficava perto da frente de explotação para possuir um controle bom da geologia dos primeiros metros. Adicionalmente, na mesma linha de reconhecimento uma seção sísmica de reflexão de alta resolução (com geófonos de 40 Hz separado 5 m) foi obtida para ter outro método geofísico de contraste. Neste estudo nós apresentamos os resultados obtidos e a interpretação combinada deles. https://hdl.handle.net/10481/23463 https://hdl.handle.net/10481/23462 Tomografia sísmica de alta resolução com gerador de ondas elásticas Mendes, Manuela; Teixidó Ullod, Teresa Several seismic surveys were carried out in the urban Palmela region (Azeitão), using 48 channel seismograph and single geophone per channel. The scope was mainly to test the efficiency and reliability of seismic source, an elastic wave generator using an accelerated hammer drop, to produce shallow velocity models with high resolution. A 300 m profile was acquired and the position based on constant topography and neighbouring the wells location previously drilled for aquifers delineation. Despite the presence of significant urban and coherent noise, the seismic source revealed effective to sum several shots and enhancing the ratio signal/noise. First arrivals processing illustrate clearly the geological structures until 60 m depth. A preliminary stack section did not support the findings in the first arrivals study. To resolve the difference, the field reflection data are being reprocessed to provide more details about the layering and lateral structures already observed in the refraction data. https://hdl.handle.net/10481/23462