Dr. Sebastián López Profile

Dr. Sebastián López

at Univ de Las Palmas de Gran Canaria

SPIE Involvement:

Editor | Author

Publications (24)

Proceedings Article | 11 October 2018 Presentation

Setting up an autonomous hyperspectral flying platform for precision agriculture (Conference Presentation)

Aythami Salvador Rodriguez Valentin, Pablo Horstrand, José Fco. López , Sebastián López

Proceedings Volume 10792, 1079206 (2018) https://doi.org/10.1117/12.2503096

KEYWORDS: Agriculture, Sensors, Unmanned aerial vehicles, Inspection, Cameras, RGB color model, Vegetation, Software development, Spatial resolution, Earth observing sensors

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Proceedings Article | 9 October 2018 Presentation + Paper

A hardware-friendly algorithm for compressing hyperspectral images

Raúl Guerra, María Díaz, Yubal Barrios, Sebastián López, Roberto Sarmiento

Proceedings Volume 10792, 1079208 (2018) https://doi.org/10.1117/12.2500493

KEYWORDS: Image compression, Chromium, Signal to noise ratio, Hyperspectral imaging, Sensors, Image processing, Image quality, Satellites, Real time image processing, Onboard cameras

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Proceedings Article | 5 October 2017 Presentation + Paper

A FPGA implementation for linearly unmixing a hyperspectral image using OpenCL

Raúl Guerra, Sebastián López, Roberto Sarmiento

Proceedings Volume 10430, 104300D (2017) https://doi.org/10.1117/12.2280768

KEYWORDS: Hyperspectral imaging, Field programmable gate arrays, Electromagnetism, Algorithm development, Imaging systems, Visible radiation, RGB color model, Image processing, Detection and tracking algorithms, Active remote sensing

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Proceedings Article | 24 October 2016 Presentation + Paper

A new comparison of hyperspectral anomaly detection algorithms for real-time applications

María Díaz, Sebastián López, Roberto Sarmiento

Proceedings Volume 10007, 100070D (2016) https://doi.org/10.1117/12.2244297

KEYWORDS: Spectral resolution, Detection and tracking algorithms, Image fusion, Sensors, Binary data, Computer simulations, Visualization, Hyperspectral imaging, Imaging systems, Sensor performance

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Due to the high spectral resolution that remotely sensed hyperspectral images provide, there has been an increasing interest in anomaly detection. The aim of anomaly detection is to stand over pixels whose spectral signature differs significantly from the background spectra. Basically, anomaly detectors mark pixels with a certain score, considering as anomalies those whose scores are higher than a threshold. Receiver Operating Characteristic (ROC) curves have been widely used as an assessment measure in order to compare the performance of different algorithms. ROC curves are graphical plots which illustrate the trade- off between false positive and true positive rates. However, they are limited in order to make deep comparisons due to the fact that they discard relevant factors required in real-time applications such as run times, costs of misclassification and the competence to mark anomalies with high scores. This last fact is fundamental in anomaly detection in order to distinguish them easily from the background without any posterior processing.

An extensive set of simulations have been made using different anomaly detection algorithms, comparing their performances and efficiencies using several extra metrics in order to complement ROC curves analysis. Results support our proposal and demonstrate that ROC curves do not provide a good visualization of detection performances for themselves. Moreover, a figure of merit has been proposed in this paper which encompasses in a single global metric all the measures yielded for the proposed additional metrics. Therefore, this figure, named Detection Efficiency (DE), takes into account several crucial types of performance assessment that ROC curves do not consider. Results demonstrate that algorithms with the best detection performances according to ROC curves do not have the highest DE values. Consequently, the recommendation of using extra measures to properly evaluate performances have been supported and justified by the conclusions drawn from the simulations.

Proceedings Article | 24 October 2016 Presentation + Paper

A new hyperspectral image compression paradigm based on fusion

Raúl Guerra, José Melián, Sebastián López, Roberto Sarmiento

Proceedings Volume 10007, 100070F (2016) https://doi.org/10.1117/12.2242891

KEYWORDS: Image fusion, Hyperspectral imaging, Image compression, Image processing, Multispectral imaging, Image restoration, Image resolution, Image sensors, Sensors, Signal to noise ratio

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Proceedings Article | 20 October 2015 Paper

A novel hardware-friendly algorithm for hyperspectral linear unmixing

Raúl Guerra, Lucana Santos, Sebastián López, Roberto Sarmiento

Proceedings Volume 9646, 96460I (2015) https://doi.org/10.1117/12.2196109

KEYWORDS: Hyperspectral imaging, Signal to noise ratio, Image processing, Error analysis, Computer simulations, Hyperspectral simulation, Interference (communication), Detection and tracking algorithms, Calcite, Remote sensing

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Linear unmixing of hyperspectral images has rapidly become one of the most widely utilized tools for analyzing the content of hyperspectral images captured by state-of-the-art remote hyperspectral sensors. The aforementioned unmixing process consists of the following three sequential steps: dimensionality estimation, endmember extraction and abundances computation. Within this procedure, the first two steps are by far the most demanding from a computational point of view, since they involve a large amount of matrix operations. Moreover, the complex nature of these operations seriously difficult the hardware implementation of these two unmixing steps, leading to non-optimized implementations which are not able to satisfy the strict delay requirements imposed by those applications under real-time or near real-time requirements. This paper uncovers a new algorithm which is capable of estimating the number of endmembers and extracting them from a given hyperspectral image with at least the same accuracy than state-of-the-art approaches while demanding a much lower computational effort, with independence of the characteristics of the image under analysis. In particular, the proposed algorithm is based on the concept of orthogonal projections and allows performing the estimation of the number of end- members and their extraction simultaneously, using simple operations, which can be also easily parallelized. In this sense, it is worth to mention that our algorithm does not perform complex matrix operations, such as the inverse of a matrix or the extraction of eigenvalues and eigenvectors, which makes easier its ulterior hardware. The experimental results obtained with synthetic and real hyperspectral images demonstrate that the accuracy obtained with the proposed algorithm when estimating the number of endmembers and extracting them is similar or better than the one provided by well-known state-of-the-art algorithms, while the complexity of the overall process is significantly reduced.

Proceedings Article | 17 November 2014 Paper

FPGA implementation of the hyperspectral Lossy Compression for Exomars (LCE) algoritm.

Aday García, L. Santos, S. López, G. Callicó, J. López, R. Sarmiento

Proceedings Volume 9247, 924705 (2014) https://doi.org/10.1117/12.2069493

KEYWORDS: Field programmable gate arrays, Image compression, Control systems, Algorithms, Hyperspectral imaging, Remote sensing, Signal processing, Sensors, Digital signal processing, Error analysis

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Proceedings Article | 15 October 2014 Paper

A novel highly-parallel algorithm for linearly unmixing hyperspectral images

Raúl Guerra, Sebastián López, Gustavo Callico, Jose López, Roberto Sarmiento

Proceedings Volume 9247, 92470H (2014) https://doi.org/10.1117/12.2068332

KEYWORDS: Hyperspectral imaging, Image processing, Signal to noise ratio, Reconstruction algorithms, Evolutionary algorithms, Computer simulations, Mathematical modeling, Image quality, Image filtering, Image analysis

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Proceedings Article | 22 May 2014 Paper

Efficient lossy compression implementations of hyperspectral images: tools, hardware platforms, and comparisons

Aday García, Lucana Santos, Sebastián López, Gustavo Callicó, Jose Lopez, Roberto Sarmiento

Proceedings Volume 9124, 912408 (2014) https://doi.org/10.1117/12.2051132

KEYWORDS: Field programmable gate arrays, Image compression, Hyperspectral imaging, Satellites, Algorithms, Sensors, Signal processing, Digital signal processing, Neodymium, Control systems

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Proceedings Article | 22 May 2014 Paper

On the acceleration of the N-FINDER algorithm for hyperspectral endmembers extraction

Raul Guerra, Sebastian López, Gustavo Callicó, Jose Lopez, Roberto Sarmiento

Proceedings Volume 9124, 91240H (2014) https://doi.org/10.1117/12.2050868

KEYWORDS: Hyperspectral imaging, Principal component analysis, Image processing, Evolutionary algorithms, Phase modulation, Signal to noise ratio, Data modeling, Feature extraction, Computer simulations, Algorithm development

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Proceedings Article | 28 May 2013 Paper

A hierarchical scheduling and management solution for dynamic reconfiguration in FPGA-based embedded systems

T. Cervero, A. Gómez, S. López, R. Sarmiento, J. Dondo, F. Rincón, J. C. López

Proceedings Volume 8764, 87640J (2013) https://doi.org/10.1117/12.2021270

KEYWORDS: Field programmable gate arrays, Embedded systems, Multimedia, Ions, Control systems, Systems modeling, Logic, Matrices, Lanthanum, Digital signal processing

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Proceedings Article | 12 October 2011 Paper

Lossy hyperspectral image compression with state-of-the-art video encoder

Lucana Santos, Sebastian López, Gustavo Callicó, Jose F. López, Roberto Sarmiento

Proceedings Volume 8183, 81830G (2011) https://doi.org/10.1117/12.898523

KEYWORDS: Image compression, Hyperspectral imaging, Computer programming, Signal to noise ratio, Video, Video compression, Video coding, Algorithm development, Image quality standards, Standards development

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Proceedings Article | 3 May 2011 Paper

Scalable 2D architecture for H.264 SVC deblocking filter with reconfiguration capabilities for on-demand adaptation

T. Cervero, A. Otero, E. de la Torre, S. López, G. Callicó, T. Riesgo, R. Sarmiento

Proceedings Volume 8067, 80670K (2011) https://doi.org/10.1117/12.887951

KEYWORDS: Scalable video coding, Field programmable gate arrays, Clocks, Video, Standards development, Electroluminescence, Neodymium, Image processing, Chemical elements, Computer programming

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Proceedings Article | 3 May 2011 Paper

Performance analysis of the scalable video coding (SVC) extension of H.264/AVC for constrained scenarios

N. Suarez, Gustavo Callico, Sebastian Lopez, Jose Lopez, Roberto Sarmiento

Proceedings Volume 8067, 80670J (2011) https://doi.org/10.1117/12.888269

KEYWORDS: Scalable video coding, Video, Standards development, Video coding, On-screen displays, Spatial resolution, Signal to noise ratio, Temporal resolution, Computer programming, Lanthanum

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Proceedings Article | 28 May 2009 Paper

Anisotropic quality measurement applied to H.264 video compression

G. Callico, Sebastián Lopez, Salvador Gabarda, Elena Gil, Gabriel Cristobal, José Lopez, Roberto Sarmiento

Proceedings Volume 7363, 73630I (2009) https://doi.org/10.1117/12.821652

KEYWORDS: Image quality, Video compression, Anisotropy, Quality measurement, Video, Image compression, Image quality standards, Computer programming, Quantization, Visual system

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Proceedings Article | 28 May 2009 Paper

Survey of reconfigurable architectures for multimedia applications

T. Cervero, S. López, G. Callicó, F. Tobajas, V. de Armas, J. López, R. Sarmiento

Proceedings Volume 7363, 736303 (2009) https://doi.org/10.1117/12.821713

KEYWORDS: Multimedia, Field programmable gate arrays, Computer architecture, Switches, Data communications, Array processing, Computer programming, Process control, Signal processing, Video processing

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Proceedings Article | 10 May 2007 Paper

Toward the implementation of a baseline H.264/AVC decoder onto a reconfigurable architecture

S. López, A. Kanstein, J. López, M. Berekovic, R. Sarmiento, J.-Y. Mignolet

Proceedings Volume 6590, 65900A (2007) https://doi.org/10.1117/12.722042

KEYWORDS: Video, Embedded systems, Digital filtering, Video coding, Profiling, Computer programming, Control systems, Multimedia, Digital signal processing, Quantization

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Proceedings Article | 10 May 2007 Paper

Optimizing coarse-grain reconfigurable hardware utilization through multiprocessing: an H.264/AVC decoder example

Andreas Kanstein, Sebastian López Suárez, Bjorn De Sutter

Proceedings Volume 6590, 65900C (2007) https://doi.org/10.1117/12.722077

KEYWORDS: Video, Computer programming, Digital signal processing, Transform theory, Information technology, Embedded systems, Profiling, Video compression, Multimedia, System on a chip

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Proceedings Article | 30 June 2005 Open Access

Practical considerations for real-time super-resolution implementation techniques over video coding platforms

Gustavo Callico, Sebastian Lopez, Rafael Peset Llopis, Ramanathan Sethuraman, Antonio Nunez, Jose Lopez, Margarita Marrero, Roberto Sarmiento

Proceedings Volume 5837, (2005) https://doi.org/10.1117/12.608322

KEYWORDS: Intelligence systems, Algorithm development, Image processing, Video, Computer programming, Image quality, Super resolution, Image resolution, Motion estimation, Video surveillance

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Proceedings Article | 30 June 2005 Paper

A low-cost bidimensional smart pixel network for video coding operations

S. Lopez, G. Callico, J. Lopez, R. Sarmiento

Proceedings Volume 5837, (2005) https://doi.org/10.1117/12.608263

KEYWORDS: Discrete wavelet transforms, Image processing, Video coding, Multimedia, Prototyping, Wavelets, Computer programming, Control systems, Photodetectors, Video compression

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Proceedings Article | 30 June 2005 Paper

A quarter pixel precision motion estimation architecture for H.264/AVC video coding

S. Lopez, F. Tobajas, A. Villar, J. Bienes, V. de Armas, G. Callico, J. Lopez, R. Sarmiento

Proceedings Volume 5837, (2005) https://doi.org/10.1117/12.608240

KEYWORDS: Motion estimation, Computer architecture, Multiplexers, Video coding, Autoregressive models, Distortion, Signal processing, Image processing, Standards development, Field programmable gate arrays

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Proceedings Article | 30 June 2005 Paper

Real-time super-resolution over raw video sequences

D. Barreto, G. M. Callico, S. Lopez, L. Garcia, A. Nunez

Proceedings Volume 5837, (2005) https://doi.org/10.1117/12.608561

KEYWORDS: Motion estimation, Video, Image segmentation, Lawrencium, Super resolution, Spatial resolution, Reconstruction algorithms, Computer programming, Image processing algorithms and systems, Image restoration

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Proceedings Article | 21 April 2003 Paper

0.25-µm technology arithmetic codec for mobile multimedia communicators

Alberto Alvarez, Sebastian Lopez, Jose Lopez, Roberto Sarmiento

Proceedings Volume 5117, (2003) https://doi.org/10.1117/12.499051

KEYWORDS: Computer programming, Image compression, Image processing, Multimedia, Wavelets, Data modeling, Telecommunications, Data compression, Prototyping, Image transmission

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Proceedings Article | 18 April 2003 Paper

Hand veins segmentation and matching under adverse conditions

Sebastian Lopez, Albano Gonzalez

Proceedings Volume 5119, (2003) https://doi.org/10.1117/12.499035

KEYWORDS: Image processing, Veins, Image segmentation, Image acquisition, Biometrics, System identification, Mathematical morphology, Image filtering, Cameras, Imaging systems

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