Valery Naranjo

Prof. Dr. Valery Naranjo


Research Focus & Metrics

Academic Career Length

30Years (1997-Present)

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

Representative Publications

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20 March 2019 in BioMedical Engineering OnLine
Verified
Journal Article
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PDF file
ADAndres Diaz-Pinto
Andres Diaz-Pinto
SMSandra Morales
Sandra Morales
VNValery Naranjo
Valery Naranjo
TKThomas Köhler
Thomas Köhler
JMJose M. Mossi
Jose M. Mossi
ANAmparo Navea
Amparo Navea
Most current algorithms for automatic glaucoma assessment using fundus images rely on handcrafted features based on segmentation, which are affected by the performance of the chosen segmentation method and the extracted features. Among other characteristics, convolutional neural networks (CNNs) are known because of their ability to learn highly discriminative features from raw pixel intensities. In this paper, we employed five different ImageNet-trained models (VGG16, VGG19, InceptionV3, ResNet50 and Xception) for automatic glaucoma assessment using fundus images. Results from an extensive validation using cross-validation and cross-testing strategies were compared with previous works in the literature. Using five public databases (1707 images), an average AUC of 0.9605 with a 95% confidence interval of 95.92–97.07%, an average specificity of 0.8580 and an average sensitivity of 0.9346 were obtained after using the Xception architecture, significantly improving the performance of other state-of-the-art works. Moreover, a new clinical database, ACRIMA, has been made publicly available, containing 705 labelled images. It is composed of 396 glaucomatous images and 309 normal images, which means, the largest public database for glaucoma diagnosis. The high specificity and sensitivity obtained from the proposed approach are supported by an extensive validation using not only the cross-validation strategy but also the cross-testing validation on, to the best of the authors’ knowledge, all publicly available glaucoma-labelled databases. These results suggest that using ImageNet-trained models is a robust alternative for automatic glaucoma screening system. All images, CNN weights and software used to fine-tune and test the five CNNs are publicly available, which could be used as a testbed for further comparisons.

1 October 2020 in Computer Methods and Programs in Biomedicine
Verified
Journal Article
Closed access
JSJulio Silva-Rodríguez
Julio Silva-Rodríguez
ACAdrián Colomer
Adrián Colomer
MSMaría A. Sales
María A. Sales
Rafael Molina-CarmonaRafael Molina-Carmona
Rafael Molina-Carmona
VNValery Naranjo
Valery Naranjo

1 October 2014 in Medical Image Analysis
Verified
Journal Article
Closed access
RRRina D. Rudyanto
Rina D. Rudyanto
SKSjoerd Kerkstra
Sjoerd Kerkstra
EREva M. van Rikxoort
Eva M. van Rikxoort
CFCatalin Fetita
Catalin Fetita
PBPierre-Yves Brillet
Pierre-Yves Brillet
BGBram van Ginneken
Bram van Ginneken

9 January 2013 in IEEE Transactions on Medical Imaging
Verified
Journal Article
Closed access
SMSandra Morales
Sandra Morales
VNValery Naranjo
Valery Naranjo
JAJesús Angulo
Jesús Angulo
Mariano AlcanizMariano Alcaniz
Mariano Alcaniz
The algorithm proposed in this paper allows to automatically segment the optic disc from a fundus image. The goal is to facilitate the early detection of certain pathologies and to fully automate the process so as to avoid specialist intervention. The method proposed for the extraction of the optic disc contour is mainly based on mathematical morphology along with principal component analysis (PCA). It makes use of different operations such as generalized distance function (GDF), a variant of the watershed transformation, the stochastic watershed, and geodesic transformations. The input of the segmentation method is obtained through PCA. The purpose of using PCA is to achieve the grey-scale image that better represents the original RGB image. The implemented algorithm has been validated on five public databases obtaining promising results. The average values obtained (a Jaccard's and Dice's coefficients of 0.8200 and 0.8932, respectively, an accuracy of 0.9947, and a true positive and false positive fractions of 0.9275 and 0.0036) demonstrate that this method is a robust tool for the automatic segmentation of the optic disc. Moreover, it is fairly reliable since it works properly on databases with a large degree of variability and improves the results of other state-of-the-art methods.

1 March 2016 in Measurement
Verified
Journal Article
Open access
PZPablo Salvador Zuriaga
Pablo Salvador Zuriaga
VNValery Naranjo
Valery Naranjo
RIRicardo Insa
Ricardo Insa
PTPaulo Teixeira
Paulo Teixeira

13 February 2020 in Sensors
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Journal Article
Open access
PDF file
ACAdrián Colomer
Adrián Colomer
Jorge IgualJorge Igual
Jorge Igual
VNValery Naranjo
Valery Naranjo
Estimated blind people in the world will exceed 40 million by 2025. To develop novel algorithms based on fundus image descriptors that allow the automatic classification of retinal tissue into healthy and pathological in early stages is necessary. In this paper, we focus on one of the most common pathologies in the current society: diabetic retinopathy. The proposed method avoids the necessity of lesion segmentation or candidate map generation before the classification stage. Local binary patterns and granulometric profiles are locally computed to extract texture and morphological information from retinal images. Different combinations of this information feed classification algorithms to optimally discriminate bright and dark lesions from healthy tissues. Through several experiments, the ability of the proposed system to identify diabetic retinopathy signs is validated using different public databases with a large degree of variability and without image exclusion.