César Sanz

Prof. César Sanz

Universidad Politécnica de Madrid, Madrid, Spain
orcid

Research Focus & Metrics

Academic Career Length

25Years (2002-Present)

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

Representative Publications

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31 May 2021 in Sensors
Verified
Journal Article
Open access
PDF file
GUGemma Urbanos
Gemma Urbanos
AMAlberto Martín-Pérez
Alberto Martín-Pérez
GVGuillermo Vazquez
Guillermo Vazquez
MVMarta Villanueva
Marta Villanueva
MVManuel Villa
Manuel Villa
CSCésar Sanz
César Sanz
Hyperspectral imaging techniques (HSI) do not require contact with patients and are non-ionizing as well as non-invasive. As a consequence, they have been extensively applied in the medical field. HSI is being combined with machine learning (ML) processes to obtain models to assist in diagnosis. In particular, the combination of these techniques has proven to be a reliable aid in the differentiation of healthy and tumor tissue during brain tumor surgery. ML algorithms such as support vector machine (SVM), random forest (RF) and convolutional neural networks (CNN) are used to make predictions and provide in-vivo visualizations that may assist neurosurgeons in being more precise, hence reducing damages to healthy tissue. In this work, thirteen in-vivo hyperspectral images from twelve different patients with high-grade gliomas (grade III and IV) have been selected to train SVM, RF and CNN classifiers. Five different classes have been defined during the experiments: healthy tissue, tumor, venous blood vessel, arterial blood vessel and dura mater. Overall accuracy (OACC) results vary from 60% to 95% depending on the training conditions. Finally, as far as the contribution of each band to the OACC is concerned, the results obtained in this work are 3.81 times greater than those reported in the literature.

17 July 2018 in Sensors
Verified
Journal Article
Open access
PDF file
GFGiordana Florimbi
Giordana Florimbi
Himar FabeloHimar Fabelo
Himar Fabelo
Emanuele TortiEmanuele Torti
Emanuele Torti
RLRaquel Lazcano
Raquel Lazcano
DMDaniel Madronal
Daniel Madronal
RSRoberto Sarmiento
Roberto Sarmiento
The use of hyperspectral imaging (HSI) in the medical field is an emerging approach to assist physicians in diagnostic or surgical guidance tasks. However, HSI data processing involves very high computational requirements due to the huge amount of information captured by the sensors. One of the stages with higher computational load is the K-Nearest Neighbors (KNN) filtering algorithm. The main goal of this study is to optimize and parallelize the KNN algorithm by exploiting the GPU technology to obtain real-time processing during brain cancer surgical procedures. This parallel version of the KNN performs the neighbor filtering of a classification map (obtained from a supervised classifier), evaluating the different classes simultaneously. The undertaken optimizations and the computational capabilities of the GPU device throw a speedup up to 66.18× when compared to a sequential implementation.

1 February 2018 in IEEE Transactions on Consumer Electronics
Verified
Journal Article
Closed access
MGMatias J. Garrido
Matias J. Garrido
FPFernando Pescador
Fernando Pescador
MCMiguel Chavarrías
Miguel Chavarrías
PLP. J. Lobo
P. J. Lobo
CSCésar Sanz
César Sanz
Future video coding (FVC) will be the next generation video coding standard. Yet in the first stages of the standardization process, it is expected to replace high efficiency video coding beyond 2020. One of the enhancements in discussion is the adaptive multiple core transform, which uses five different types of 2-D discrete sine/cosine transforms (DCT-II, DCT-V, DCT-VIII, DST-I, and DST-VII) and up to 64 x 64 transform unit sizes. This schema, increases the computational complexity of both, encoder and decoder. In this paper, a deeply pipelined high performance architecture to implement the five transforms for 4 x 4, 8 x 8, 16 x 16, and 32 x 32 sizes is proposed. The design has been described in VHDL and it has been synthesized for different Field-programmable gate array chips, being able to process up 182 fps@3840 x 2160 for 4 x 4 transform sizes. Up the best of our knowledge, this is the first implementation of an architecture for the FVC Adaptive Multiple Core Transform supporting 4 x 4, 8 x 8, 16 x 16, and 32 x 32 sizes.

25 April 2019 in IEEE Transactions on Consumer Electronics
Verified
Journal Article
Closed access
MGMatias J. Garrido
Matias J. Garrido
FPFernando Pescador
Fernando Pescador
MCMiguel Chavarrías
Miguel Chavarrías
PLP. J. Lobo
P. J. Lobo
CSCésar Sanz
César Sanz
Versatile video coding (VVC) will be the next generation video coding standard, which is expected to replace HEVC in CE devices, such as tablets, smartphones, and TV sets beyond 2020. The new standard will still be based on transform, quantization, and entropy coding, but a multiple transform selection scheme has been proposed, involving three different types of 2-D Discrete Sine/Cosine transforms (DCT-II, DCT-VIII, and DST-VII), and the transform unit sizes range from 4×4 to 64×64. To handle the computational complexity of these algorithms, it is useful to explore hardware solutions that could be employed as accelerators. In this paper, a high performance architecture to implement the aforementioned 2-D transform types for 4×4, 8×8, 16×16, and 32×32 sizes is proposed. The design has been synthesized for low, medium, and high-end FPGA chips, being able to process up to 23 fps@3840×2160 for 32×32 transform sizes and up to 86 fps@3840×2160 for pictures containing an even distribution of the four block sizes. Moreover, these performance results have been obtained with a moderate consumption of hardware resources.

1 June 2017 in Journal of Systems Architecture
Verified
Journal Article
Closed access
RLR. Lazcano
R. Lazcano
DMD. Madroñal
D. Madroñal
RSRuben Salvador
Ruben Salvador
KDK. Desnos
K. Desnos
MPM. Pelcat
M. Pelcat
CSCésar Sanz
César Sanz

18 June 2013 in IEEE Transactions on Consumer Electronics
Verified
Journal Article
Closed access
FPF. Pescador
F. Pescador
MCMiguel Chavarrías
Miguel Chavarrías
MGM. J. Garrido
M. J. Garrido
EJEduardo Juarez
Eduardo Juarez
CSCésar Sanz
César Sanz
High Efficiency Video Coding (HEVC) is a new video coding standard created by the JCT-VC group within ISO/IEC and ITU-T. HEVC is targeted to provide the same quality as H.264 at about half of the bit-rate and will replace soon to its predecessor in multimedia consumer applications. Up to now, only a few decoder implementations have been reported, most of them oriented to carry out a complexity analysis. In this paper, a DSP-based implementation of the HEVC HM9.0 decoder is presented. Up to the best of our knowledge, it is the first DSP-based implementation shown in the scientific literature. Several tests have been carried out to measure the decoder performance and the computational load distribution among its functional blocks. These results have been compared with the ones obtained with the decoder implementations reported up to date. Finally, based on the results obtained in previous works regarding software optimization of DSP-based decoders, realtime could be achieved for SD formats with a single DSP after optimizing our HEVC decoder. For HD formats, multi-DSP technology will be needed.