Sebastian Salazar

Dr. Sebastian Salazar


Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

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

Representative Publications

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7 December 2018 in IEEE Transactions on Image Processing
Verified
Journal Article
Closed access
SSSebastian Salazar
Sebastian Salazar
ECEduardo Cabal-Yepez
Eduardo Cabal-Yepez
JRJuan M. Ramos-Arreguin
Juan M. Ramos-Arreguin
GBGuillermo Botella
Guillermo Botella
Luis M. Ledesma-CarrilloLuis M. Ledesma-Carrillo
Luis M. Ledesma-Carrillo
SLSergio Ledesma
Sergio Ledesma
Outdoor images are used in a vast number of applications, such as surveillance, remote sensing, and autonomous navigation. The greatest issue with these types of images is the effect of environmental pollution: haze, smog, and fog originating from suspended particles in the air, such as dust, carbon and water drops, which cause degradation to the image. The elimination of this type of degradation is essential for the input of computer vision systems. Most of the state-of-the-art research in dehazing algorithms is focused on improving the estimation of transmission maps, which are also known as depth maps. The transmission maps are relevant because they have a direct relation to the quality of the image restoration. In this paper, a novel restoration algorithm is proposed using a single image to reduce the environmental pollution effects, and it is based on the dark channel prior and the use of morphological reconstruction for the fast computing of transmission maps. The obtained experimental results are evaluated and compared qualitatively and quantitatively with other dehazing algorithms using the metrics of the Peak Signal-to-Noise Ratio (PSNR) and Structural Similarity (SSIM) index; based on these metrics, it is found that the proposed algorithm has improved performance compared to recently introduced approaches.

18 October 2019 in Sensors
Verified
Journal Article
Open access
COCésar J. Ortiz-Echeverri
César J. Ortiz-Echeverri
SSSebastian Salazar
Sebastian Salazar
Juvenal RodriguezJuvenal Rodriguez
Juvenal Rodriguez
RLRoberto Augusto Gómez Loenzo
Roberto Augusto Gómez Loenzo
Brain-Computer Interfaces (BCI) are systems that allow the interaction of people and devices on the grounds of brain activity. The noninvasive and most viable way to obtain such information is by using electroencephalography (EEG). However, these signals have a low signal-to-noise ratio, as well as a low spatial resolution. This work proposes a new method built from the combination of a Blind Source Separation (BSS) to obtain estimated independent components, a 2D representation of these component signals using the Continuous Wavelet Transform (CWT), and a classification stage using a Convolutional Neural Network (CNN) approach. A criterion based on the spectral correlation with a Movement Related Independent Component (MRIC) is used to sort the estimated sources by BSS, thus reducing the spatial variance. The experimental results of 94.66% using a k-fold cross validation are competitive with techniques recently reported in the state-of-the-art.

25 July 2018 in Journal of Electronic Imaging
Verified
Journal Article
Closed access
SSSebastian Salazar
Sebastian Salazar
ICIvan Cruz-Aceves
Ivan Cruz-Aceves
JRJuan-Manuel Ramos-Arreguin
Juan-Manuel Ramos-Arreguin
The Journal of Electronic Imaging (JEI), copublished bimonthly with the Society for Imaging Science and Technology, publishes peer-reviewed papers that cover research and applications in all areas of electronic imaging science and technology.

15 February 2022 in Brain Sciences
Verified
Journal Article
Open access
PDF file
YSYamanki Santander
Yamanki Santander
SSSebastian Salazar
Sebastian Salazar
WGWilfrido Jacobo Paredes Garcia
Wilfrido Jacobo Paredes Garcia
HGHumberto Guendulain-Arenas
Humberto Guendulain-Arenas
Saúl Tovar-ArriagaSaúl Tovar-Arriaga
Saúl Tovar-Arriaga
Dementia is a neurodegenerative disease that leads to the development of cognitive deficits, such as aphasia, apraxia, and agnosia. It is currently considered one of the most significant major medical problems worldwide, primarily affecting the elderly. This condition gradually impairs the patient’s cognition, eventually leading to the inability to perform everyday tasks without assistance. Since dementia is an incurable disease, early detection plays an important role in delaying its progression. Because of this, tools and methods have been developed to help accurately diagnose patients in their early stages. State-of-the-art methods have shown that the use of syntactic-type linguistic features provides a sensitive and noninvasive tool for detecting dementia in its early stages. However, these methods lack relevant semantic information. In this work, we propose a novel methodology, based on the semantic features approach, by using sentence embeddings computed by Siamese BERT networks (SBERT), along with support vector machine (SVM), K-nearest neighbors (KNN), random forest, and an artificial neural network (ANN) as classifiers. Our methodology extracted 17 features that provide demographic, lexical, syntactic, and semantic information from 550 oral production samples of elderly controls and people with Alzheimer’s disease, provided by the DementiaBank Pitt Corpus database. To quantify the relevance of the extracted features for the dementia classification task, we calculated the mutual information score, which demonstrates a dependence between our features and the MMSE score. The experimental classification performance metrics, such as the accuracy, precision, recall, and F1 score (77, 80, 80, and 80%, respectively), validate that our methodology performs better than syntax-based methods and the BERT approach when only the linguistic features are used.

17 November 2020 in IEEE Access
Verified
Journal Article
Open access
SSSebastian Salazar
Sebastian Salazar
HJHugo Moreno Jimenez
Hugo Moreno Jimenez
COCesar Javier Ortiz-Echeverri
Cesar Javier Ortiz-Echeverri
Gerardo FloresGerardo Flores
Gerardo Flores
In this paper, a method to remove the smoke effects in laparoscopic images is presented. The proposed method is based on an image-to-image conditional generative adversarial network endowed with a dark channel’s embedded guide mask. The obtained experimental results were evaluated and quantitatively compared with desmoking state-of-art methods using the Peak Signal-to-Noise Ratio (PSNR) metrics and Structural Similarity (SSIM) index. Those results throw an improved performance compared with relevant works. Also, the processing time required by our method is 92 frames per second; a processing time that sets the foundation for a possible real-time implementation in a more modest embedded system.

28 May 2019 in EURASIP Journal on Image and Video Processing
Verified
Journal Article
Open access
PDF file
SSSebastian Salazar
Sebastian Salazar
JRJuan-Manuel Ramos-Arreguín
Juan-Manuel Ramos-Arreguín
JPJesús-Carlos Pedraza-Ortega
Jesús-Carlos Pedraza-Ortega
JRJ Rodríguez-Reséndiz
J Rodríguez-Reséndiz
Outdoor images can be degraded due to the particles in the air that absorb and scatter light. The produced degradation generates contrast attenuation, blurring, and distortion in pixels, resulting in low visibility. These limit the efficiency of computer vision systems such as target tracking, surveillance, and pattern recognition. In this paper, we propose a fast and effective method, through modification in the computation of the dark channel which significantly reduces the artifacts generated in the restored images presented when using the ordinary dark channel. According to our experimental results, our method produces better results than some state-of-the-art methods in both efficiency and restoration quality. The processing time in tests shows that the method is adequate for images with high-resolution and real-time video processing.