Pedro J. Pardo

• Ph.D.
• Professor (Associate) at University of Extremadura

Federated Learning has emerged as a promising approach for maintaining data privacy across distributed environments, enabling training on a diverse range of devices from high-performance servers to low-power gadgets. Despite its potential, managing numerous data sources can strain these devices, particularly those with limited capabilities, leading...

Los entornos de realidad virtual (RV) ofrecen cada vez más contenidos de mayor calidad y utilizan diferentes técnicas informáticas para mejorar la experiencia de uso final. En este trabajo, aplicamos técnicas de calibración del dispositivo de RV, creamos diferentes fuentes de luz, midiendo la radiancia de éstas en un entorno real e introducimos tex...

El avance tecnológico que se ha producido en los últimos 10 años está permitiendo de forma progresiva que la información digital se pueda mostrar en 3D y visualizar mediante gafas de Realidad Virtual (RV). Al igual que la tecnología avanza y se adapta, las pruebas para detectar deficiencias visuales del color también se van adecuando a las nuevas t...

Virtual reality (VR) environments are increasingly offering higher quality content. They use different computing techniques to improve the final user experience. In this work, we create different light sources and introduce hyperspectral textures for the object reflectance to boost the VR environment’s quality. In addition, we perform a quantitativ...

In virtual reality technology, it is necessary to develop improvements and apply new techniques that allow rapid progress and innovative development. Nowadays, virtual reality devices have not yet demonstrated the great potential they could develop in the future. One main reason for this is the lack of precision to represent three-dimensional scena...

In recent years, there have been very important advances in graphic computing and technology related to the capture and representation of real objects in both 2 and 3 dimensions. One of these technologies is virtual reality, which can be incorporated into common tasks in research laboratories, especially in laboratories related to color vision and...

Due to the increase in the use of virtual reality systems, the requirement for quality in it has also increased. The most important factor may be the quality of the visual appearance of the scenes shown in it. One of the aspects that affects the visual appearance, among other things, is the color constancy or the ability of an object to be perceive...

Virtual reality has become a great multimedia tool in which it is possible to represent 3D content. It can be used for many applications such as video games, telemedicine, teleworking or airplane simulators. However, visual appearance is an aspect that needs to be further improved if virtual reality wants to take on a much more professional use. Sh...

Technology is constantly evolving and, consequently, all the technological advances taking place are regularly integrated into the daily life of society. During recent years, there has been a trend towards virtual resources such as teleworking, telemedicine and e-commerce. In many countries, this virtualisation process has been accelerated by the c...

Virtual reality has reached a great maturity in recent years. However, the quality of its visual appearance still leaves room for improvement. One of the most difficult features to represent in real-time 3D rendered virtual scenes is color fidelity, since there are many factors influencing the faithful reproduction of color. In this paper we introd...

COVID19 has challenged every world health system. In Spain, not only hospitals are overcrowded but health specialists and essential workers do not have adequate Personal Protective Equipment (PPE), or enough diagnostic or assistance equipment. In this sense, coronavirusmaker.org was born as a national maker association to help solve this lack. This...

Color deficiency tests are well known all over the world. However, there are not applications that attempt to simulate these tests with total color accuracy in virtual reality using spectral color computing. In this work a study has been made of the tools that exist in the market in VR environments to simulate the experience of users suffering from...

Virtual reality has experienced a strong advance in recent years, its use in industries such as video games, automotive and medicine is now a reality. Previous work has determined that color is one of the most important characteristics when it comes to creating a sense of realism in the user. Therefore, through the use of spectral techniques we hav...

We introduced a Color Management System (CMS) within the virtual reality software whose native color space is RGB. The starting point was the chromatic characterization of two commercial HUD display devices (Oculus Rift CV1 and HTC Vive) and the definition of the colorimetric profiles associated with these devices. Then, a third part color manageme...

El avance tecnológico sigue su progreso inexorable desde que en los años 50 del siglo XX se inventase el transistor y diera comienzo la era digital. Este progreso lo podemos apreciar en muchos aspectos de la vida cotidiana, como en nuestras capacidades de comunicación, nuestras capacidades de cómputo e incluso, en aspectos lúdicos como televisión,...

La realidad virtual (VR) intenta representar en tiempo real escenas de la realidad, que se reconstruyen en los dispositivos informáticos mediante diferentes plataformas. Pero ¿cómo gestionan estas plataformas, internamente el color? Y ¿hasta qué punto son un fiel reflejo de la realidad? Los sistemas de gestión del color establecen una serie de tran...

Trabajos previos han demostrado la gran mejoría de los sistemas de visualización basados en Head Mounted Display (HMD) y realidad virtual. En concreto, se realizó un estudio de valoración subjetiva de escenas de realidad virtual en las que era posible visualizar réplicas de obras de arte. En dicho estudio se analizaban varios aspectos relacionados...

La realidad virtual (VR) se está introduciendo, en mayor o menor medida, en casi todos los ámbitos de nuestra vida cotidiana. Cuando oímos VR, generalmente lo asociamos a los videojuegos, pero actualmente podemos encontrar VR en visitas a museos, en el sector del turismo, en el ámbito de la medicina (simuladores para la formación médica, tratamient...

Virtual reality devices are having a great development nowadays. These Head-Mounted-Displays (HMD) based systems allow visual immersive experiences in virtual environments. Recently, the group of authors have made the chromatic characterization of two of the most worldwide used virtual reality devices [1]. Likewise, they have developed a colour man...

Previous works have shown the great improvement of visualization systems based on Head Mounted Displays (HMD) and Virtual Reality (VR). In these previous pieces of research the authors carried out a subjective evaluation study of virtual reality scenes in which it was possible to visualize artwork replicas [1]. In that study, several aspects relate...

Students are immerse in a digital world, in which master classes are not enough; they need to interact with new technological trends. In addition, each student is different and they have his or her own difficulties, consequently sometimes the suggested methods or activities for the study are too general and do not meet the particular needs of each...

This work presents a series of didactic simulations to improve the teaching of colour at different educational levels. Specifically, the objective of these simulations was to show the student concepts related to metameric colour pairs. The simulations were developed using the software POV-Ray. This program was chosen because of its ability to gener...

The measurement of the quality of light in both indoor and outdoor environments is a relevant topic that has gained attention due to its multiple applications. Recently, two colour rendering measurement recommendations have been approved, one sponsored by the Illuminating Engineering Society IES T-30 and the other by the International Commission on...

In this work, we studied the chromatic characterization of Head Mounted Displays (HMD) applied to Virtual Reality (VR) with the purpose of obtaining a better colour fidelity reproduction. We used two of the latest commercial version of HMD through Unity, a game development platform. It has been verified that no type of colour management is performe...

Virtual Reality (VR) has witnessed a great development during last years. Head Mounted Displays (HMD) allow visual immersive experiences in virtual environments and will have many applications, in both recreational and professional fields, provided that the quality of the immersive experience is satisfactory. Different commercial devices oriented t...

Virtual Reality (VR) has witnessed a great development during last years. Head Mounted Displays (HMD) allow visual immersive experiences in virtual environments and will have many applications, in both recreational and professional fields, provided that the quality of the immersive experience is satisfactory. Different commercial devices oriented t...

Head-mounted displays allow us to go through immersive experiences in virtual reality and are expected to be present in more and more applications in both recreational and professional fields. In this context, recent years have witnessed significant advances in rendering techniques following physical models of lighting and shading. The aim of this...

Currently much of the pre-harvest fruit valuation is still done by farmers or technicians that visually inspect the pieces of fruit. However, this process has great limitations since their decisions have high subjectivity and a thorough analysis of the whole production, or even a significant part of it, is unapproachable. Therefore, computer vision...

This paper addresses the way in which the random selection of different sets of samples influences the values of two colour-rendering indices analogous to the ones proposed by the International Commission on Illumination (CIE Publ. 13.3, 1995), Ra, and the Illuminating Engineering Society (IES Technical Memorandum TM-30-15, 2015), Rf. We report res...

We have used 13 experimental datasets (7420 colour pairs) to study the performance of the weighting function for lightness proposed by the CIEDE2000 colour-difference formula, because it has been suggested that this function can be improved by using the weighting function for lightness SL = 1 adopted by the CIE94 colour-difference formula. Using th...

This work presents an educational simulation to support students’ learning about the formation of the rainbow. The main aim of the simulation is to provide our students with a didactic tool in addition to their traditional laboratory practice, which can be easily implemented in e-learning teaching platforms. A system consisting of a flask filled wi...

The CIE Colour Rendering Index (CRI), defined in CIE 13.3-1995, in particular the general colour rendering index, Ra, is widely adopted and used by the lighting industry, in regulatory documents and in international and regional standards and specifications. However, limitations of the CRI have been recently addressed, especially for solid-state li...

Fifty years ago the most widespread method of teaching was purely receptive. Discovery learning followed afterwards, and now is widely accepted that meaningful learning is the more effective educational system. What will be the preferred pedagogical method in a few years? How many years will be meaningful learning considered as the best teaching me...

Head Mounted Displays (HMD) allows immersive experiences in virtual worlds and it would be expected to have many applications, in both fields: recreational and professional. The aim of this paper is to check the accuracy of the visual appearance of real objects captured through a 3D scanner, rendered in a PC and displayed in the latest development...

We report on an experience carried out to show the didactic use of concept maps as tools for the development of a progressive explanation of the colour perception of a dress with ambiguous colours. Concept maps are used to promote a conceptual change in our students trying to answer the question: Why some people perceive the dress as blue & black a...

Este trabajo está enfocado a la distinción y análisis de diferentes variedades de ciruelas utilizando técnicas de tratamiento de imágenes y minería de datos. En concreto, se analizan cuatro conjuntos de datos en los que se presentan tres variedades de ciruela en fase de maduración temprana: Black Splendor, OwenT y Angelino. La principal dificultad...

Existing color quality indices for light sources provide broad information about different dimensions related to color quality. Color fidelity, harmony, and gamut area are concepts related to these indices, and industry requests this information. For the last few years, LED light sources have been widely used at home and at work, and now a color re...

In this work, we present an online test designed to ascertain what type of misconceptions people may have about color perception. It is noteworthy that only 15.7% of the over 20,000 respondents answered correctly, and that the vast majority (78.2%) of incorrect response patterns on our test matched to just four sequences, corresponding with four ty...

Wireless Communication technologies are in continuous evolution. Around the world, many Universities try to provide innovative laboratory courses to train their students in this field. In this paper, a ubiquitous laboratory course for wireless communications is described. The laboratory course has been designed so that the students have to complete...

We present research carried out with university students taking the subject “Concept Maps in Teaching” within the Master’s Degree on Research in Teaching and Learning of the Experimental Sciences. The objective of this study was to elaborate a reasoning model, created using concept maps, that captures modes of thinking of expert teachers about solv...

This chapter discusses the application of the PBL methodology on Information and Communications Technology (ICT). First, a small collection of various works focusing on ICT through the PBL methodology is detailed. Then, the overall project which implements the PBL methodology at the Centro Universitario de Mérida is presented. Subsequently, three c...

This chapter sets out to establish, as conclusions, the major contributions made in this joint work dedicated to projects based learning applied to engineering. It also aims to provide a critical overview of the current system of university education and those that are, in our view, future works on this subject line.

Color measurements have traditionally been linked to expensive and difficult to handle equipment. The set of mathematical transformations that are needed to transfer a color that we observe in any object that doesn’t emit its own light (which is usually called a color-object) so that it can be displayed on a computer screen or printed on paper is n...

In a previous work [J. Opt. Soc. Am. A 29, A209 (2012)], we presented a visual color discrimination experiment whose results established the existence of a relationship between the correlated color temperature (CCT) of a light source and the color discrimination capacities of the observers. The results indicated the existence of a statistically sig...

The use of active learning methodologies is an issue of great concern for improving education quality. In this paper, the authors provide an innovative point of view for an Intellectual Property (IP) course. This course is designed by engineers for engineers. The course has been designed so that the students have to complete three different project...

This work presents the design, development, testing and validation of a Photonic Virtual Laboratory, highlighting the study of LEDs. The study was conducted from a conceptual, experimental and didactic standpoint, using e-learning and m-learning platforms. Specifically, teaching tools that help ensure that our students perform significant learning...

A study was conducted to quantify the effectiveness of concept maps in learning physics in engineering degrees. The following research question was posed: What was the difference in learning results from the use of concept maps to study a particular topic in an engineering course? The study design was quasi-experimental and used a post-test as a me...

We study the misconceptions about colour that most people hold, determining the general phenomenological laws that govern them. Concept mapping was used to combat the misconceptions which were found in the application of a test specifically designed to determine these misconceptions, while avoiding the possible misleading inductions that could have...

While the educational value of computer simulations is broadly accepted, it is also true that the student using them often encounters learning difficulties in not being able to fully identify what is seen to happen in the simulated model with what can be observed in reality. This is mainly caused by the highly schematic graphical interface of the s...

The development of skills through active learning methodologies has been demonstrated to be appropriate in environments where students must acquire particular professional capacities. Problem-Based Learning (PBL) embeds strudents' learning processes in real-life problems so, they can integrate different subjects in a common project that they need t...

Portable video-game consoles are comparable in color reproduction to other digital chromatic stimuli generators such as personal computers equipped with CRT or TFT screens but with the advantage of having a defined hardware. Such is the case with the Nintendo DSi for which the user can only adjust the luminance on a five-level scale by software. If...

It is well known that there are different preferences in correlated color temperature of light sources for daily living activities or for viewing artistic paintings. There are also data relating the capacity of observers to make judgments on color differences with the spectral power distribution of the light source used. The present work describes...

This study compared the educational effects of computer simulations developed in a hyper-realistic virtual environment with the educational effects of either traditional schematic simulations or a traditional optics laboratory. The virtual environment was constructed on the basis of Java applets complemented with a photorealistic visual output. Thi...

The quality of a light source can be measured against various criteria – colour rendering, durability, etc. Another criterion is the quality of the colour of the objects it illuminates. Traditionally, this aspect has been associated almost exclusively with that of colour rendering, but the emergence of new light-emitting diode technology light sour...

During recent years, research on colour vision has used traditional visual colorimeters, cathode ray tubes (CRT), and personal-computer controlled LCD-TFT screens to generate chromatic stimuli. We here explore the possibilities offered by a particular family of electronic devices whose use has lately been expanding rapidly, and which have one or mo...

A metameric colour matching test was designed to study inter-observer variability. Blue-yellow metameric matching to a white-light continuum was used to define the optimal wavelengths at which each of eight non-colour-defective observers achieved a match. The tests involved chromatic stimuli on a 2° bipartite field, with a white-light continuum pre...