N. Aleixos

N. Aleixos
Universitat Politècnica de València | UPV · Department of Graphic Engineering

PhD

About

116
Publications
31,348
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4,415
Citations
Citations since 2016
38 Research Items
2649 Citations
20162017201820192020202120220100200300400500
20162017201820192020202120220100200300400500
20162017201820192020202120220100200300400500
20162017201820192020202120220100200300400500
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Publications

Publications (116)
Chapter
In the 3D modeling of products, the use of an adequate methodology that ensures the capture of the design intention is very important. The sequence of operations is key, like for instance, the sketches have to be completely restricted and the references of the modelling functions have to be correctly chosen without generating unwanted dependency re...
Chapter
In engineering, the 3D model of a product is essential. A 3D model allows making modifications by editing the characteristic modeling functions, which implies knowing in detail the process followed in the modeling. In addition, the flexibility in the configuration is limited, since the modifications are made on geometry and parameters that are depe...
Article
Loquat (Eriobotrya japonica L.) is an important fruit for the economy of some regions of Spain that is very susceptible to mechanical damage and physiological disorders. These problems depreciate its value and prevent it from being exported. Visible (VIS) and near infrared (NIR) hyperspectral imaging was used to discriminate between external and in...
Article
Pasta is mostly composed by wheat flour and water. Nevertheless, flour can be partially replaced by fibers to provide extra nutrients in the diet. However, fiber can affect the technological quality of pasta if not properly distributed. Usually, determinations of parameters in pasta are destructive and time-consuming. The use of Near Infrared-Hyper...
Chapter
Spectral methods usually produce a large amount of data, and have been greatly applied to food and agricultural products. These products demand several analyses to determine different parameters, that will further indicate their quality. There have been several approaches reported to deal with multi-target regression in recent years, with different...
Article
Full-text available
RobHortic is a remote-controlled field robot that has been developed for inspecting the presence of pests and diseases in horticultural crops using proximal sensing. The robot is equipped with colour, multispectral, and hyperspectral (400–1000 nm) cameras, located looking at the ground (towards the plants). To prevent the negative influence of dire...
Article
Pomegranate fruit cv. ‘Mollar de Elche’ were collected at seven different harvest times. Colour and hyperspectral images of the intact fruit and arils were acquired at each harvest. Physicochemical properties such as total soluble solids, titratable acidity, maturity index, BrimA, internal colour, total phenolic compounds content and antioxidant ac...
Article
Full-text available
One of the most studied techniques for the non-destructive determination of the internal quality of fruits has been visible and near-infrared (VIS-NIR) reflectance spectroscopy. This work evaluates a new non-destructive in-line VIS-NIR spectroscopy prototype for in-line identification of five apple varieties, with the advantage that it allows the s...
Article
Persimmon fruit cv. ‘Rojo Brillante’ is an astringent cultivar due to its content of soluble tannins, which are insolubilised during the ripening of the fruit. Traditionally, the consumption of this cultivar has only been possible when the fruit is overripe and the texture is soft. Postharvest treatments based on exposing fruits to high CO2 concent...
Article
Internal quality Hyperspectral imaging Computer vision The internal quality of nectarines (Prunus persica L. Batsch var. nucipersica) cv. 'Big Top' (yellow flesh) and 'Magique' (white flesh) has been inspected using hyperspectral trans-mittance imaging. Hyperspectral images of intact fruits were acquired in the spectral range of 630e900 nm using tr...
Article
Full-text available
The use of remote sensing to map the distribution of plant diseases has evolved considerably over the last three decades and can be performed at different scales, depending on the area to be monitored, as well as the spatial and spectral resolution required. This work describes the development of a small low-cost field robot (Remotely Operated Vehi...
Article
The collection of oranges normally begins before they have reached the typical orange colour. Moreover, citrus fruits are subjected to certain degreening treatments that depend on the standard citrus colour index (CCI) at harvest. In order to facilitate the measure of this index, a free application that uses image processing techniques has been dev...
Article
The astringency removal with high CO2 concentration is the most widely used postharvest treatment prior to commercialise astringent persimmon cultivars. In this process the anaerobic respiration promoted gives rise to an accumulation of acetaldehyde which reacts with the soluble tannins (ST), responsible of astringency. The objective of this work w...
Article
The feasibility of using visible and near-infrared spectroscopy technology combined with multivariate analysis to discriminate cv. ‘Big Top’ and cv. ‘Diamond Ray’ nectarines has been studied. These varieties are very difficult to differentiate visually on the production line but show important differences in taste that affects the acceptance by fin...
Article
Product inspection is essential to ensure good quality and to avoid fraud. New nectarine cultivars with similar external appearance but different physicochemical properties may be mixed in the market, causing confusion and rejection among consumers, and consequently affecting sales and prices. Hyperspectral reflectance imaging in the range of 450–1...
Article
Full-text available
Visible and near-infrared spectroscopy has been widely used as a non-invasive and rapid-assessment technique for the quality control of agricultural products. In this study, 325 samples of nectarines representing two commercial varieties, cv. ‘Big Top’ and cv. ‘Magique’, were analysed by visible and near-infrared diffuse reflectance spectroscopy (V...
Article
One of the current challenges of persimmon postharvest research is the development of non-destructive methods that allow determination of the internal properties of the fruit, such as maturity, flesh firmness and astringency. This study evaluates the usefulness of hyperspectral imaging in the 460–1020 nm range as a non-destructive tool to achieve t...
Article
Early control of fruit quality requires reliable and rapid determination techniques. Therefore, the food industry has a growing interest in non-destructive methods such as spectroscopy. The aim of this study was to evaluate the feasibility of visible and near-infrared (NIR) spectroscopy, in combination with multivariate analysis techniques, to pred...
Article
The internal quality of intact persimmon cv. ‘Rojo Brillante’ was assessed trough visible and near infrared hyperspectral imaging. Fruits at three stages of commercial maturity were exposed to different treatments with CO2 to obtain fruit with different ripeness and level of astringency (soluble tannin content). Spectral and spatial information wer...
Article
Full-text available
Computer vision systems are becoming a scientific but also a commercial tool for food quality assessment. In the field, these systems can be used to predict yield, as well as for robotic harvesting or the early detection of potentially dangerous diseases. In postharvest handling, it is mostly used for the automated inspection of the external qualit...
Article
Tangent and Corner Vertices Detection (TCVD) is a method to detect corner vertices and tangent points in sketches using parametric cubic curves approximation, which is capable to detect corners with a high accuracy and a very low false positive rate, and also to detect tangent points far above other methods in literature. In this article, we presen...
Article
BACKGROUND: Grapevine cluster morphology influences the quality and commercial value of wine and table grapes. It is routinely evaluated by subjective and inaccurate methods that do not meet the requirements set by the food industry. Novel 2D and 3D machine vision technologies emerge as promising tools for its automatic and fast evaluation. RESULTS...
Chapter
Individual items of any agricultural commodity are different from each other in terms of colour, shape or size. Furthermore, as they are living thing, they change their quality attributes over time, thereby making the development of accurate automatic inspection machines a challenging task. Machine vision-based systems and new optical technologies...
Chapter
The mechanisation and automation of citrus harvesting is considered to be one of the best options to reduce production costs. Computer vision technology has been shown to be a useful tool for fresh fruit and vegetable inspection, and is currently used in post-harvest fruit and vegetable automated grading systems in packing houses. Although computer...
Article
Background Berry weight, berry number and cluster weight are key parameters for yield estimation for wine and tablegrape industry. Current yield prediction methods are destructive, labour-demanding and time-consuming. In this work, a new methodology, based on image analysis was developed to determine cluster yield components in a fast and inexpensi...
Article
Background and AimsBunch compactness is a key feature determining grape and wine composition because tight bunches show a less homogeneous ripening, and are prone to greater fungal disease incidence. The Organisation Internationale de la Vigne et du Vin descriptor, the most recent method for the assessment of bunch compactness, requires visual insp...
Chapter
The use of sketch based interfaces is not so extended due to the problems they present at the moment, like the lack of robustness, repeatability and reliability. The current recognisers used on line in some interactive applications do not offer ideal solutions, they use to be rigid and the success ratio in the classification decreases when the numb...
Patent
Full-text available
Procedimiento automático para determinar la compacidad de un racimo de uva en modo continuo, sobre una cinta transportadora sita en bodega
Patent
Full-text available
Procedimiento para la estimación automática de los componentes de la producción de un racimo de vid mediante visión artificial, que comprende las etapas siguientes: a) Capturar una imagen RGB original de un racimo de vid con una cámara en una campana de adquisición; b) Procesar una imagen RGB original para obtener una imagen con círculos definitivo...
Article
Este trabajo estudia el potencial de la visión artificial y la robótica agrícola para desarrollar modelos predictivos de producción de uva y potencial enológico del viñedo de forma no destructiva, rápida, objetiva y fiable. La amplia variabilidad espacial y temporal en rendimiento (kg/ha) y potencial enológico de la uva requiere desarrollar métodos...
Article
Full-text available
Hyperspectral systems are characterised by offering the possibility of acquiring a large number of images at different consecutive wavebands. To ensure reliable and repeatable results using this kind of optical sensors, the intensity shown by the objects in the different spectral images must be independent from the differences in sensitivity of the...
Article
La estimación de gran parte de los elementos que intervienen en el rendimiento del viñedo se realiza en la actualidad de forma manual, lo que la convierte en costosa, lenta y subjetiva. Una posible alternativa para automatizar algunas de estas tareas y dotarlas de una mayor objetividad viene de la visión artificial. Esta tecnología se ha convertido...
Article
The vibratory behaviour of citrus fruits is studied using slow-motion cameras in order to gain a better understanding of the parameters involved in fruit detachment when mechanical harvesting is done using shakers. Single citrus fruits with a small portion of stem were vibrated using strokes from 60 mm to 180 mm and frequencies from 3 Hz to 18 Hz....
Article
The mechanisation and automation of citrus harvesting is considered to be one of the best options to reduce production costs. Computer vision technology has been shown to be a useful tool for fresh fruit and vegetable inspection, and is currently used in post-harvest fruit and vegetable automated grading systems in packing houses. Although computer...
Article
The berry size of wine-grapes has often been considered to influence wine composition and quality, as it is related to the skin-to-pulp ratio of the berry and the concentration of skin-located compounds that play a key role in the wine quality. The size and weight of wine-grapes are usually measured by hand, making it a slow, tedious and inaccurate...
Article
The berry size of wine-grapes has often been considered to influence wine composition and quality, as it is related to the skin-to-pulp ratio of the berry and the concentration of skin-located compounds that play a key role in the wine quality. The size and weight of wine-grapes are usually measured by hand, making it a slow, tedious and inaccurate...
Article
Hyperspectral imaging systems allow to detect the initial stages of decay caused by fungi in citrus fruit automatically, instead of doing it manually under dangerous ultraviolet illumination, thus preventing the fungal infestation of other sound fruit and, consequently, the enormous economical losses generated. However, these systems present the di...
Article
Green mold (Penicillium digitatum) and blue mold (Penicillium italicum) are important sources of postharvest decay affecting the commercialization of mandarins. These fungi infections produce enormous economic losses in mandarin production if early detection is not carried out. Nowadays, this detection is performed manually in dark chambers, where...
Article
Some recent approaches have been presented as simple and highly accurate corner finders in the sketches including curves, which is useful to support natural human–computer interaction, but these in most cases do not consider tangent vertices (smooth points between two geometric entities, present in engineering models), what implies an important dra...
Article
Full-text available
Computer vision systems are powerful tools to automate inspection tasks in agriculture. Typical target applications of such systems include grading, quality estimation, yield prediction and monitoring, among others. The capabilities of an artificial vision system go beyond the limited human capacity to evaluate long-term processes objectively and p...
Chapter
Nowadays, there is a growing demand for quality fruits and vegetables that are simple to prepare and consume, like minimally processed fruits. These products have to accomplish some particular characteristics to make them more attractive to the consumers, like a similar appearance and the total absence of external defects. Although recent advances...
Chapter
Machine vision has become a key technology in the area of quality control of horticultural products due to the increasing quality demands of manufacturers and customers, providing a fast and reliable method of inspecting features such as ripeness, size, weight, shape, colour, the presence of blemishes and diseases, the presence or absence of fruit...
Article
Important advances in natural calligraphic interfaces for CAD (Computer Aided Design) applications are being achieved, enabling the development of CAS (Computer Aided Sketching) devices that allow facing up to the conceptual design phase of a product. Recognizers play an important role in this field, allowing the interpretation of the user’s intent...
Article
Full-text available
Nowadays, there is a growing demand for quality fruits and vegetables that are simple to prepare and consume, like minimally processed fruits. These products have to accomplish some particular characteristics to make them more attractive to the consumers, like a similar appearance and the total absence of external defects. Although recent advances...
Article
Currently, important advances are being carried out in CAD (Computer Aided Design) applications; however, these advances have not yet taken place for CAS (Computer Aided Sketching) applications. These applications are intended to replace complex menus with natural interfaces that support sketching for commands and drawing, but the recognition proce...
Article
Full-text available
Artificial vision systems are powerful tools for the automatic inspection of fruits and vegetables. Typical target applications of such systems include grading, quality estimation from external parameters or internal features, monitoring of fruit processes during storage or evaluation of experimental treatments. The capabilities of an artificial vi...
Article
Full-text available
Artificial vision systems are powerful tools for the automatic inspection of fruits and vegetables. Typical target applications of such systems include grading, quality estimation from external parameters or internal features, monitoring of fruit processes during storage or evaluation of experimental treatments. The capabilities of an artificial vi...
Article
Full-text available
Hyperspectral imaging systems are starting to be used as a scientific tool for food quality assessment. A typical hyperspectral image is composed of a set of a relatively wide range of monochromatic images corresponding to continuous wavelengths that normally contain redundant information or may exhibit a high degree of correlation. In addition, co...
Conference Paper
Full-text available
One of the main problems in the segmentation of freehand sketches is the difficulty of tuning the parameters involved in the process. Commonly, these parameters are chosen empirically from the observation of segmentation results in training sets. However, this approach rarely gets the best set of parameters, especially when the parameters depend on...
Article
Full-text available
Early automatic detection of fungal infections in post-harvest citrus fruits is especially important for the citrus industry because only a few infected fruits can spread the infection to a whole batch during operations such as storage or exportation, thus causing great economic losses. Nowadays, this detection is carried out manually by trained wo...
Article
The best alternative for reducing citrus production costs is mechanization. Machine vision is a reliable technology for the automatic inspection of fresh fruits and vegetables that can be adapted to harvesting machines. In these, fruits can be inspected before sending them to the packinghouse and machine vision provides important information for su...
Article
Full-text available
Currently, important advances are carried out in CAD (Computer Aided Design) applications; however these advances have not taken place for CAS (Computer Aided Sketching) applications. Although natural interfaces for CAD applications are not solved yet, works based on sketching devices have been explored to some extent. The recognition paradigm we p...