Juan Francisco Zapata Pérez

Juan Francisco Zapata Pérez
Universidad Politécnica de Cartagena | UPCT · Department of Electronics, Computer Technology and Projects

PhD

About

58
Publications
13,927
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574
Citations
Introduction
Juan Francisco Zapata Pérez currently works at the Department of Electronics, Computer Technology and Projects , Universidad Politécnica de Cartagena. Juan does research in Bioengineering, Electronic Engineering and Industrial Engineering. Their current project is 'Wireless sensor networks for ambient assisted living'.

Publications

Publications (58)
Article
Full-text available
The power dissipation of a pipelined analog-to-digital converter (ADC) depends on different design strategies. In this brief communication, an 11-bit pipelined ADC consisting of five stages with 2.5 effective bit resolution is described. The circuit combines two main techniques to improve power dissipation, such as sharing OTAs between adjacent ADC...
Article
Full-text available
This paper provides a comparative performance evaluation of local features for images from CMOS APS sensors affected by fixed pattern noise for different combinations of common detectors and descriptors. Although numerous studies report comparisons of local features designed for ordinary visual images, their performance on images with fixed pattern...
Article
Full-text available
Thermal spray technology, which involves the Atmospheric Plasma Spraying (APS), encompasses a category of coating processes that supply surface properties to protect or improve the performance of a substrate or component. The coating produced by this technology is built by overlapped splats, whose morphology determines the coating properties. In th...
Conference Paper
Abstract—This work presents a new analog architecture to perform image convolution for deep learning purposes in CMOS imagers in the analog domain. The architecture is focused to reduce both power dissipation and data transfer between memory and the analog operators. It uses mixed signal multiply and add operators arranged following a row-parallel...
Article
Full-text available
This paper presents a 9-bit, 2-stage cyclic analog to digital converter (ADC) with a variable bias current control circuitry to reduce its power dissipation. Each stage outputs a three-bit digital word and the circuit requires four subcycles to perform a whole conversion. Since the accuracy required is higher in the first stage and first subcycle a...
Article
Full-text available
This document provides a comparative evaluation of the performance of a deep learning network for different combinations of parameters and hyper-parameters. Although there are numerous studies that report on performance in deep learning networks for ordinary data sets, their performance on small data sets is much less evaluated. The objective of th...
Article
Full-text available
Weld defects detection using X-ray images is an effective method of nondestructive testing. Conventionally, this work is based on qualified human experts, although it requires their personal intervention for the extraction and classification of heterogeneity. Many approaches have been done using machine learning (ML) and image processing tools to s...
Article
Full-text available
This paper presents a real time hardware implementation of the scale invariant feature transform (SIFT) algorithm. To achieve real time requirements, pipeline structures have been widely exploited both in the keypoint extraction and in the descriptor generation stages. Simplifications to the original algorithm have been also applied to allow a simp...
Conference Paper
iCaveats is a Project on the integration of components and architectures for embedded vision in transport and security applications. A compact and efficient implementation of autonomous vision systems is difficult to be accomplished by using the conventional image processing chain. In this project we have targeted alternative approaches, that explo...
Preprint
This paper describes a hardware proposal to speed up the process of image matching in stereo vision systems like those employed by autonomous mobile robots. This proposal combines a classical window-based matching approach with a previous stage, where key points are selected from each image of the stereo pair. In this first step the key point extra...
Article
This paper proposes an all‐hardware architecture to perform the subpixel refinement operation in the scale invariant transform algorithm. Although the literature describes several hardware implementations of this algorithm, due to its complexity, most of them are based on simplifications of it. These implementations normally exclude the subpixel re...
Article
Ubiquitous computing has been defined as ‘machines that fit the human environment instead of forcing humans to enter theirs’. An example of this type of approach is “Smart Sensory Furniture” (SSF) project. SSF is an AAL (Ambient Assisted Living) system that allows inferring a potential dangerous action of an elderly person living alone at home. Thi...
Article
nd should be recalibrated manually if the transducer response changes. We propose an automatic calibration algorithm to get an adaptive threshold which makes the sensor robust regarding the transducer degradation, a small shift in the position of the sensor, or any other variation that modifies the characteristic response of the load sensor. An imp...
Article
Nowadays, coating materials such as ceramic, metal or alloys, are widely used in the industry to improve properties of the base materials. There is growing interest in knowing the parameters governing the promotion of high quality coatings, mainly adhesion strength. It would be really interesting using Automated Measurement Tools based on Image Pro...
Conference Paper
In this work, we introduce an Ambient Assisted Living (AAL) system that allows to infer a potential dangerous action of an elderly person living alone at home. This inference is obtained by a specific sensorisation with sensor nodes and a reasoning layer embedded in a personal computer that learns of the users behavior patterns and advices when act...
Article
In this paper, a CMOS fourth-order low-frequency bandpass filter for passive pyroelectric infrared sensors is presented. The sensor is intended for use in wireless sensor nodes, demanding strict low power requirements. The final use of these sensor nodes is an ambient assisted living system for elderly people living alone at home. A NICERA RE200B p...
Article
Full-text available
In this article, we show that the dielectric constant of lead-free ferroelectric ceramics based on the solid solution (1-x)(Bi0.5Na0.5)TiO3-xBaTiO3, with compositions at or near the morphotropic phase boundary (MPB), can be tuned by a local applied electric field. Two compositions have been studied, one at the MPB, with x = 0.06 (BNBT6), and anothe...
Conference Paper
Full-text available
The objective of the work consists in the design and implementation of technique of automatic recognition of weld region. It is aimed to complete a system of automatic inspection of radiographic images of welded joints. It deals with the problem of the delimitation of the weld regions according to the general scheme of image interpretation systems...
Conference Paper
The analysis of human motion has become a major application area in computer vision. The vast majority of applications require using video cameras as main sensor for acquisition, analysis and detection of human motion. Some applications are very sensitive to the acquisition of images of people that may feel violated his right to privacy. Especially...
Article
DIA (Dispositivo Inteligente de Alarma, in Spanish) is an AAL (Ambient Assisted Living) system that allows to infer a potential dangerous action of an elderly person living alone at home. This inference is obtained by a specific sensorisation with sensor nodes (portables and fixes) and a reasoning layer embedded in a PC that learns of the users beh...
Article
The use of bed/couch occupancy sensors is imperative for certain ubiquitous computing systems such as ambient assisted living (AAL). DIA (Dispositivo Inteligente de Alarma, in Spanish) is an AAL system that allows to infer a potential dangerous action of a dependant person living alone at home. This inference is obtained by a specific sensitization...
Article
Alert intelligent device is an ambient assisted living (AAL) system that allows the evaluation of potentially dangerous situations for elderly people living alone at home. This evaluation is obtained by an ad hoc network of sensor nodes, working in conjunction with an ambient intelligence layer embedded in a personal computer that learns from user...
Conference Paper
This paper describes a fourth order continuous time band pass filter used to filter analog signals coming from passive infrared sensors (PIR). Specifications for this filter are characterized by an extremely large time constant which strongly condition the topology of the filter used. Moreover, very low power consumption is also required, since the...
Article
Accidental falls of our elderly, and physical injuries resulting, represent a major health and economic problem. Falls are the most common cause of serious injuries and are a major health threat in the stratum of older population. Early detection of a fall is a key factor when trying to provide adequate care to elderly person who has suffered an ac...
Chapter
Due to the increasing interest in collecting data related to physical activity habits and behavior of people, wireless sensor networks have emerged as one of the most appropriate technologies for applications that focus on the interest of health care and assisted living. DIA system (in Spanish, Dispositivo Inteligente de Alerta) has developed devic...
Article
In this paper, we describe an automatic system to detect, recognise, and classify welding defects in radiographic images and evaluate the performance for two neuro-classifiers based on an artificial neural network (ANN) and an adaptive-network-based fuzzy inference system (ANFIS). In a first stage, image processing techniques, including noise reduc...
Conference Paper
Ambient Assisted Living (AAL) systems demand is raising. The use of bed seat occupancy sensors is imperative for this kind of ubiquitous monitoring systems. Pressure mats are a first way to solve this feature, but several environmental dependencies make them weak to be an efficient and reliable solution for large volume deployments. Solutions based...
Conference Paper
Full-text available
In this paper, we describe an automatic system of radiographic inspection of welding. An important stage in the construction of this system is the classification of defects. In this stage, an adaptive-network-based fuzzy inference system (ANFIS) for weld defect classification was used. The results was compared with the aim to know the features that...
Article
Full-text available
In this paper, we describe an ANN with a modified performance function which is used in an automatic inspection system of welding defects in radiographic images. In a first stage, image processing techniques, including noise reduction, contrast enhancement, thresholding and labelling, were implemented to help in the recognition of weld regions and...
Article
Full-text available
One of the main problems to resolve in the processing of biomedical images is the reduction of noise. The problem is specially important if the noise has a multiplicative nature (speckle noise), for instance if the object of analysis is an ultrasonic image. In this report we carry out a review of techniques which can be used to reduce this type of...
Article
Accidental falls of our elderly, and physical injuries resulting, represent a major health and economic. Falls are the most common causes of serious injuries and a major health threats in the stratum of older population. Early detection of a fall is a key factor when trying to provide adequate care to the elderly person who has suffered an accident...
Article
In this paper, we describe an adaptive-network-based fuzzy inference system to recognise welding defects in radiographic images. In a first stage, image processing techniques, including noise reduction, contrast enhancement, thresholding and labelling, were implemented to help in the recognition of weld regions and the detection of weld defects. In...
Article
Full-text available
In general, one of the main problems to be solved in the processing of biomedical images is the noise reduction. The problem is particularly important if the noise has a multiplicative nature (speckle). We present a review of techniques that can be used to reduce this kind of noise in ultrasound images. That techniques have been used on B-mode echo...
Article
In this paper, we describe an automatic detection system to recognise welding defects in radiographic images. In a first stage, image processing techniques, including noise reduction, contrast enhancement, thresholding and labelling, were implemented to help in the recognition of weld regions and the detection of weld defects. In a second stage, a...
Conference Paper
Full-text available
In this paper, we describe an automatic classification system of welding defects in radiographic images. In a first stage, image processing techniques, including noise reduction, contrast enhancement, thresholding and labelling, were implemented to help in the recognition of weld regions and the detection of weld defects. In a second stage, a set o...
Conference Paper
Full-text available
This paper introduces an ubiquitous wireless network infrastructure to support an assisted living at home system. This system integrates a set of smart sensors which are designed to provide care assistence and security to elderly citizens living at home alone. The system facilitates privacy by performing local computation, it supports heterogeneous...
Conference Paper
Full-text available
In this paper, we describe an automatic detection system to recognise welding defects in radiographic images. In a first stage, image processing techniques, including noise reduction, contrast enhancement, thresholding and labelling, were implemented to help in the recognition of weld regions and the detection of weld defects. In a second stage, a...
Conference Paper
Full-text available
Radiographic inspection is a well-established testing method to detect weld defects. However, interpretation of radiographic films is a difficult task. The reliability of such interpretation and the expense of training suitable experts have allowed that the efforts being made towards automation in this field. In this paper, we describe an automatic...
Conference Paper
A system that performs the detection and tracking of a face in real-time in real video sequences is presented in this paper. The face is detected in a complex environment by a model of human colour skin. Very good results are obtained, since the colour segmentation removes almost all the complex background and it is realized to a very high-speed, m...
Article
Full-text available
A hybrid snake algorithm is presented in this paper. The procedure is based on combining a dynamic balloon force, a GVF force and a traditional gradient force. The balloon force is modified in order to increase the capture range and convergence speed of active contour in a dynamic way. Our interest is to give the balloon force a bigger preponderanc...
Conference Paper
The Retinex is an image enhancement algorithm that improves the brightness, contrast and sharpness of an image. This work discusses an easy and rapid DSP implementation of the Retinex algorithm on a hard-ware/software platform which integrates MATLAB/Simulink, Texas Instruments (TI) eXpressDSP Tools and C6000 digital signal processing (DSP) target....
Article
Full-text available
This work discusses a hardware/software platform for educational purpose which integrates MAT- LAB/Simulink, Texas Instruments (TI) eXpressDSP Tools and C6000 digital signal processing (DSP) target let develop and validate digital signal processing designs fro m concept through code, in a typical professional vision design-simulation-implementation...
Article
A procedure is presented for robust head tracking by a deformable model. The head onto of the scene is modelled as an active contour whose location and size are constantly updated in order to track the head movement. The resultant system is a real-time, illumination and head-rotation invariant robust head tracker. The procedure is based on combinin...
Article
Full-text available
In first place, in this paper, the basic process of parallel code implementation is discussed for a VLIW architecture. Parallel code modules allow the implementation of a contour active (snake) for segmentation and tracking of endocardium in echocardiographic images. In second place, this work discusses the performance obtained through this design...
Conference Paper
Radiographic inspection is a well-established testing method to detect welding defects. However, interpretation of radiographic films is a difficult task. The reliability of such interpretation and the expense of training suitable experts the efforts being made towards automation in this field. In this paper, we describe an automatic detection syst...
Article
Full-text available
Gracias a los recientes avances producidos en electrónica y telecomunicaciones, la fonocardiografía se presenta actualmente, tras muchos años en el olvido, como un método sencillo, rápido, barato y no invasivo capaz de obtener un diagnóstico remoto y objetivo del estado funcional del corazón mediante sistemas electrónicos que procesen los sonidos c...
Conference Paper
Full-text available
In this paper a DSP-based active contour model for tracking of the endocardium in a sequence of echocar- diographic images is presented. If a contour is available in the first frame of a sequence, the contours in the subsequent frames are segmented. Deformable active contours is a technique that combine geometry, physics and approximation theory in...
Article
In this paper a high-speed procedure for motion tracking of endocardium is presented. If a contour is available in the first frame of a sequence, the contours on the subsequent frames are segmented. Deformable active contours is a technique that combine geometry, physics and approximation theory to solve problems with fundamental important into med...
Article
The use of active contour models to track the boundaries of anatomic structures in medical images is a technique that has attracted a great number of efforts during the last decade. Segmentation techniques based in deformable active contours were proposed first by Kass et al. Because of the problems appearing using these models, some solutions have...

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Projects (2)
Project
The overall objective of AAL is to enhance the quality of life of older adults. The topics covered by the programme include management of chronic conditions, social inclusion, access to the self-serve society, mobility of older adults, management of daily activities, support from informal carers (e.g. family and friends) and occupation in life. In our case, Wireless sensor networks (WSN), sometimes called wireless sensor and actuator networks (WSAN), are spatially distributed autonomous sensors to monitor physical or environmental conditions, such as temperature, sound, pressure, etc. and to cooperatively pass their data through the network to a main location.
Project
Referencia: TEC2015-66878-C3-2-R Entidad Financiadora: MINISTERIO DE ECONOMÍA Y COMPETITIVIDAD Investigador Responsable: GINÉS DOMÉNECH ASENSI Número de Investigadores Participantes en el Equipo Investigador: 4 Fecha Inicio: 01/01/2016 Fecha Fin: 31/12/2018