20 results on '"segmentation models"'
Search Results
2. A Complete Pipeline to Extract Temperature from Thermal Images of Pigs.
- Author
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Bekhit, Rodania and Reimert, Inonge
- Subjects
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CONVOLUTIONAL neural networks , *THERMOGRAPHY , *PROCESS capability , *ARTIFICIAL intelligence , *DEEP learning , *LABORATORY animals - Abstract
Using deep learning or artificial intelligence (AI) in research with animals is a new interdisciplinary area of research. In this study, we have explored the potential of thermal imaging and AI in pig research. Thermal cameras play a vital role in obtaining and collecting a large amount of data, and AI has the capabilities of processing and extracting valuable information from these data. The amount of data collected using thermal imaging is huge, and automation techniques are therefore crucial to find a meaningful interpretation of the changes in temperature. In this paper, we present a complete pipeline to extract temperature automatically from a selected Region of Interest (ROI). This system consists of three stages: the first one checks whether the ROI is completely visible to observe the thermal temperature, and then the second stage uses an encoder–decoder structure of a convolution neural network to segment the ROI, if the condition was met at stage one. In the last stage, the maximum temperature is extracted and saved in an external file. The segmentation model showed good performance, with a mean Pixel Class accuracy of 92.3%, and a mean Intersection over Union of 87.1%. The extracted temperature observed by the model entirely matched the manually observed temperature. The system showed reliable results to be used independently without human intervention to determine the temperature in the selected ROI in pigs. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
3. Enhanced lung image segmentation using deep learning.
- Author
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Gite, Shilpa, Mishra, Abhinav, and Kotecha, Ketan
- Subjects
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DEEP learning , *IMAGE segmentation , *MACHINE learning , *LUNGS , *LUNG diseases , *MEDICAL personnel - Abstract
With the advances in technology, assistive medical systems are emerging with rapid growth and helping healthcare professionals. The proactive diagnosis of diseases with artificial intelligence (AI) and its aligned technologies has been an exciting research area in the last decade. Doctors usually detect tuberculosis (TB) by checking the lungs' X-rays. Classification using deep learning algorithms is successfully able to achieve accuracy almost similar to a doctor in detecting TB. It is found that the probability of detecting TB increases if classification algorithms are implemented on segmented lungs instead of the whole X-ray. The paper's novelty lies in detailed analysis and discussion of U-Net + + results and implementation of U-Net + + in lung segmentation using X-ray. A thorough comparison of U-Net + + with three other benchmark segmentation architectures and segmentation in diagnosing TB or other pulmonary lung diseases is also made in this paper. To the best of our knowledge, no prior research tried to implement U-Net + + for lung segmentation. Most of the papers did not even use segmentation before classification, which causes data leakage. Very few used segmentations before classification, but they only used U-Net, which U-Net + + can easily replace because accuracy and mean_iou of U-Net + + are greater than U-Net accuracy and mean_iou , discussed in results, which can minimize data leakage. The authors achieved more than 98% lung segmentation accuracy and mean_iou 0.95 using U-Net + + , and the efficacy of such comparative analysis is validated. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
4. Development of an Ensembled Meta-Deep Learning Model for Semantic Road-Scene Segmentation in an Unstructured Environment.
- Author
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Sivanandham, Sangavi and Gunaseelan, Dharani Bai
- Subjects
DEEP learning ,INTELLIGENT transportation systems ,IMAGE segmentation - Abstract
Road scene segmentation is an integral part of the Intelligent Transport System (ITS) for precise interpretation of the environment and safer vehicle navigation. Traditional segmentation methods have faced difficulties in meeting the requirements of unstructured and complex image segmentation. Therefore, the Deep-Neural Network (DNN) plays a significant role in effectively segmenting images with multiple classes in an unstructured environment. In this work, semantic segmentation models such as U-net, LinkNet, FPN, and PSPNet are updated to use classification networks such as VGG19, Resnet50, Efficientb7, MobilenetV2, and Inception V3 as pre-trained backbone architectures, and the performance of each updated model is compared with the unstructured Indian Driving-Lite (IDD-Lite) dataset. In order to improve segmentation performance, a stacking ensemble approach is proposed to combine the predictions of a semantic segmentation model across different backbone architectures using a simple grid search method. Thus, four ensemble models are formed and analyzed on the IDD-Lite dataset. The two metrics Intersection over Union (IoU or Jaccard index) and Dice coefficient (F1 score) are used to assess the segmentation performance of each ensemble model. The results show that an ensemble of U-net with different backbone architectures is more efficient than other ensemble models. This model has achieved 73.12% and 76.67%, respectively, in IoU and F1 scores. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
5. Attention recurrent residual U-Net for predicting pixel-level crack widths in concrete surfaces.
- Author
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Rao, Aravinda S, Nguyen, Tuan, Le, Son T, Palaniswami, Marimuthu, and Ngo, Tuan
- Subjects
CRACKING of concrete ,STRUCTURAL health monitoring ,DEEP learning ,INSPECTION & review ,RANDOM forest algorithms ,REGRESSION analysis ,COMPOSITE columns - Abstract
Cracks in concrete structures are one of the most important indicators of structural damage, and it is a necessity to detect and measure cracks for ensuring safety and integrity of concrete structures. The widely practised approach in inspecting the structures is by performing visual inspections followed by manual estimation of crack widths. This approach is not only time-consuming, laborious, and time-intensive but also prone to subjective errors and inefficient. To address these issues, we propose a novel deep learning framework for detecting cracks and then estimating crack widths in concrete surface images. Our framework handles both small- and large-sized images and provides a prediction of crack width at locations specified by the user. The proposed framework uses Attention Recurrent Residual U-Net (Attention R2U-Net) with Random Forest regressor to predict crack width with the mean prediction error of ±0.31 mm for crack widths varying from 0 to 8.95 mm and produces the lowest absolute maximum error of 1.3 mm. Our model has a coefficient of determination (R
2 ) of 0.91, showing a non-linear mapping function with low prediction errors. We compare our model with a combination of four other segmentation models and regression models. Our proposed model has superior performance compared to other models, and one can easily adopt our framework to a variety of Structural Health Monitoring applications using Internet of Things sensors. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
6. Consumer Profile Segmentation in Online Lottery Gambling Utilizing Behavioral Tracking Data from the Portuguese National Lottery.
- Author
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Chagas, Bernardo T., Gomes, J. F. S., and Griffiths, Mark D.
- Abstract
The present study is the first to examine account-based tracking data of Portuguese online lottery players comprising the gambling activity of all active players over a one-year period (N = 154,585). The main research goal was the identification of groups or segments of players by their engagement levels (high, neutral, low) and to assess preferences in product category with the use of CHAID (Chi-Square Automatic Interaction Detection) segmentation models, based on expenditure and sociodemographic variables. Findings showed that (1) age was found to be the most influential differentiating variable in player segmentation and had a positive correlation with expenditures and wagers, (2) gender was the second most influential variable (males represented 78.7% of players), (3) education the third most influential variable and had a negative correlation with expenditure, and (4) region was the least relevant variable. The models generated several players segments that engaged in different games. Older males (54–64 years; ≥ 65 years) were the most engaged overall. Younger males (18–34 years) were the least engaged but showed preferences for lotto as did females (35–49 years). Lower educated males and older males (49 years+) with a high school education were the most engaged in instant lottery games. These findings show that Portuguese lottery players can be grouped into several segments with distinct demographic characteristics and corresponding engagement levels. These findings help support more effective marketing segmentation and will help in the targeting of responsible gambling approaches. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
7. Development and evaluation of a vision driven sensor for estimating fuel feeding rates in combustion and gasification processes
- Author
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Ögren, Yngve, Sepman, Alexey, Fooladgar, Ehsan, Weiland, Fredrik, Wiinikka, Henrik, Ögren, Yngve, Sepman, Alexey, Fooladgar, Ehsan, Weiland, Fredrik, and Wiinikka, Henrik
- Abstract
A machine vision driven sensor for estimating the instantaneous feeding rate of pelletized fuels was developed and tested experimentally in combustion and gasification processes. The feeding rate was determined from images of the pellets sliding on a transfer chute into the reactor. From the images the apparent area and velocity of the pellets were extracted. Area was determined by a segmentation model created using a machine learning framework and velocities by image registration of two subsequent images. The measured weight of the pelletized fuel passed through the feeding system was in good agreement with the weight estimated by the sensor. The observed variations in the fuel feeding correlated with the variations in the gaseous species concentrations measured in the reactor core and in the exhaust. Since the developed sensor measures the ingoing fuel feeding rate prior to the reactor, its signal could therefore help improve process control., Correspondence Address: Y. Ögren; RISE AB, Piteå, Box 726 SE-941 28, Sweden; . The Bio4Energy, a strategic research environment appointed by the Swedish government and the SwedishCenter for Gasification financed by the Swedish Energy Agency and member companies. The RE:source program finance by the Swedish Energy Agency, Vinnova and Formas. The Pulp&Fuel project financed by the European Union’s Horizon 2020 research and innovation program under grant agreement No. 818011 and the TDLAS-AI project (Swedish energy agency project 50470-1).
- Published
- 2024
- Full Text
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8. Development of an Ensembled Meta-Deep Learning Model for Semantic Road-Scene Segmentation in an Unstructured Environment
- Author
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Sangavi Sivanandham and Dharani Bai Gunaseelan
- Subjects
semantic segmentation ,ensembling algorithms ,computer vision ,IDD ,segmentation models ,road scene perception ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Road scene segmentation is an integral part of the Intelligent Transport System (ITS) for precise interpretation of the environment and safer vehicle navigation. Traditional segmentation methods have faced difficulties in meeting the requirements of unstructured and complex image segmentation. Therefore, the Deep-Neural Network (DNN) plays a significant role in effectively segmenting images with multiple classes in an unstructured environment. In this work, semantic segmentation models such as U-net, LinkNet, FPN, and PSPNet are updated to use classification networks such as VGG19, Resnet50, Efficientb7, MobilenetV2, and Inception V3 as pre-trained backbone architectures, and the performance of each updated model is compared with the unstructured Indian Driving-Lite (IDD-Lite) dataset. In order to improve segmentation performance, a stacking ensemble approach is proposed to combine the predictions of a semantic segmentation model across different backbone architectures using a simple grid search method. Thus, four ensemble models are formed and analyzed on the IDD-Lite dataset. The two metrics Intersection over Union (IoU or Jaccard index) and Dice coefficient (F1 score) are used to assess the segmentation performance of each ensemble model. The results show that an ensemble of U-net with different backbone architectures is more efficient than other ensemble models. This model has achieved 73.12% and 76.67%, respectively, in IoU and F1 scores.
- Published
- 2022
- Full Text
- View/download PDF
9. On an effective multigrid solver for solving a class of variational problems with application to image segmentation.
- Author
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Roberts, Michael, Chen, Ke, Li, Jingzhi, and Irion, Klaus L.
- Subjects
- *
MULTIGRID methods (Numerical analysis) , *ALGORITHMS , *EULER-Lagrange equations , *IMAGE segmentation , *PLYOMETRICS - Abstract
In this paper we reformulate a class of non-linear variational models for global and selective image segmentation and obtain convergent multigrid solutions. In contrast, non-linear multigrid schemes do not converge for these problems with strong non-linearity and non-smoothness (jumps). Our new approach is to reformulate the non-linear models, using splitting techniques, to generate linear models in a higher dimension which are easier to solve and amenable to the linear multigrid framework. Although splitting techniques are well studied in isolation, direct application of a splitting idea is not sufficient and it is the combination of two splitting approaches and linear multigrid theory approaches which results in a highly effective multigrid algorithm. Numerical results demonstrate the fast convergence of the new multigrid methods. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
10. Modeling, validation and verification of three-dimensional cell-scaffold contacts from terabyte-sized images
- Author
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Peter Bajcsy, Soweon Yoon, Stephen J. Florczyk, Nathan A. Hotaling, Mylene Simon, Piotr M. Szczypinski, Nicholas J. Schaub, Carl G. Simon, Mary Brady, and Ram D. Sriram
- Subjects
Co-localization ,Cellular measurements ,Cell-scaffold contact ,Segmentation models ,Contact evaluation ,Web-based verification ,Computer applications to medicine. Medical informatics ,R858-859.7 ,Biology (General) ,QH301-705.5 - Abstract
Abstract Background Cell-scaffold contact measurements are derived from pairs of co-registered volumetric fluorescent confocal laser scanning microscopy (CLSM) images (z-stacks) of stained cells and three types of scaffolds (i.e., spun coat, large microfiber, and medium microfiber). Our analysis of the acquired terabyte-sized collection is motivated by the need to understand the nature of the shape dimensionality (1D vs 2D vs 3D) of cell-scaffold interactions relevant to tissue engineers that grow cells on biomaterial scaffolds. Results We designed five statistical and three geometrical contact models, and then down-selected them to one from each category using a validation approach based on physically orthogonal measurements to CLSM. The two selected models were applied to 414 z-stacks with three scaffold types and all contact results were visually verified. A planar geometrical model for the spun coat scaffold type was validated from atomic force microscopy images by computing surface roughness of 52.35 nm ±31.76 nm which was 2 to 8 times smaller than the CLSM resolution. A cylindrical model for fiber scaffolds was validated from multi-view 2D scanning electron microscopy (SEM) images. The fiber scaffold segmentation error was assessed by comparing fiber diameters from SEM and CLSM to be between 0.46% to 3.8% of the SEM reference values. For contact verification, we constructed a web-based visual verification system with 414 pairs of images with cells and their segmentation results, and with 4968 movies with animated cell, scaffold, and contact overlays. Based on visual verification by three experts, we report the accuracy of cell segmentation to be 96.4% with 94.3% precision, and the accuracy of cell-scaffold contact for a statistical model to be 62.6% with 76.7% precision and for a geometrical model to be 93.5% with 87.6% precision. Conclusions The novelty of our approach lies in (1) representing cell-scaffold contact sites with statistical intensity and geometrical shape models, (2) designing a methodology for validating 3D geometrical contact models and (3) devising a mechanism for visual verification of hundreds of 3D measurements. The raw and processed data are publicly available from https://isg.nist.gov/deepzoomweb/data/ together with the web -based verification system.
- Published
- 2017
- Full Text
- View/download PDF
11. Modeling, validation and verification of three-dimensional cell-scaffold contacts from terabyte-sized images.
- Author
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Bajcsy, Peter, Soweon Yoon, Florczyk, Stephen J., Hotaling, Nathan A., Simon, Mylene, Szczypinski, Piotr M., Schaub, Nicholas J., Simon Jr, Carl G., Brady, Mary, and Sriram, Ram D.
- Subjects
TISSUE scaffolds ,CONFOCAL microscopy ,ATOMIC force microscopy ,ACCURACY ,SCANNING electron microscopy - Abstract
Background: Cell-scaffold contact measurements are derived from pairs of co-registered volumetric fluorescent confocal laser scanning microscopy (CLSM) images (z-stacks) of stained cells and three types of scaffolds (i.e., spun coat, large microfiber, and medium microfiber). Our analysis of the acquired terabyte-sized collection is motivated by the need to understand the nature of the shape dimensionality (1D vs 2D vs 3D) of cell-scaffold interactions relevant to tissue engineers that grow cells on biomaterial scaffolds. Results: We designed five statistical and three geometrical contact models, and then down-selected them to one from each category using a validation approach based on physically orthogonal measurements to CLSM. The two selected models were applied to 414 z-stacks with three scaffold types and all contact results were visually verified. A planar geometrical model for the spun coat scaffold type was validated from atomic force microscopy images by computing surface roughness of 52.35 nm ±31.76 nm which was 2 to 8 times smaller than the CLSM resolution. A cylindrical model for fiber scaffolds was validated from multi-view 2D scanning electron microscopy (SEM) images. The fiber scaffold segmentation error was assessed by comparing fiber diameters from SEM and CLSM to be between 0.46% to 3.8% of the SEM reference values. For contact verification, we constructed a web-based visual verification system with 414 pairs of images with cells and their segmentation results, and with 4968 movies with animated cell, scaffold, and contact overlays. Based on visual verification by three experts, we report the accuracy of cell segmentation to be 96.4% with 94.3% precision, and the accuracy of cell-scaffold contact for a statistical model to be 62.6% with 76.7% precision and for a geometrical model to be 93.5% with 87.6% precision. Conclusions: The novelty of our approach lies in (1) representing cell-scaffold contact sites with statistical intensity and geometrical shape models, (2) designing a methodology for validating 3D geometrical contact models and (3) devising a mechanism for visual verification of hundreds of 3D measurements. The raw and processed data are publicly available from https://isg.nist.gov/deepzoomweb/data/together with the web-based verification system. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
12. Формування множини Парето в задачах пошуку раціонального компромісу
- Author
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Панкратова, Наталія Дмитрівна
- Subjects
сегментаційні моделі ,штучні нейронні мережі ,segmentation models ,system analysis ,мішане лінійне програмування ,mixed linear programming ,множина парето ,519.6:539.3:681.3 [007.52] ,artificial neural networks ,системний аналіз ,pareto set - Abstract
Магістерська дисертація 108 с., 31 рис., 19. табл, 1 додаток, 17 джерел Об’єктом досліджень є процеси у складних системах із великою кількістю вхідних та вихідних параметрів. Предметом дослідження є методи формуваня множини Парето, узгодження областей значень та визначень. Мета дослідженя: 1. Розробити та дослідити методи узгодження областей значень та визначень для функцій за дискретно заданою вибіркою. 2. Створити модель формування множини Парето. Новизна: Використання нейронних мереж для формувая функціональних залежностей із подальшим формуванням множини Парето та корекції за допомогою методів узгодження областей значень та визначень. В роботі проводиться ретельна побудова методів узгодження областей значень та визначень для функцій, за дискретно заданою вибіркою. Для цього використовується апарат штучних нейронних мереж. В результаті отриманий інструментарій знаходить застосування у корекції множини Парето, яка формується із використанням комбінації нейронних мереж, що включають в себе моделі сегментації. В результаті було створено модель побудови множини Парето для системи функцій за дискретно заданою вибіркою, що дозволяє знаходити компроміс під час прийняття рішення щодо моделювання складного виробу. Master's dissertation 108 p., 31 fig., 19. table, 1 appendix, 17 sources The object of research is complex systems with a large number of input and output parameters. The subject of the research is the methods of reconstruction of the Pareto set, coordination of the domains of arguments and values. The purpose of the study: 1) Develop and investigate methods for reconciling arguments domain and values domains for tabular functions. 2) Form a Pareto domain recovery model. Novelty: The use of neural networks to restore functional dependencies with subsequent forecasting of the Pareto area and correction using methods of matching the areas of values and definitions. The work carefully constructs methods for reconciling the areas of values and arguments for functions that they are given by tabular data. The approach of the artificial neural networks is used for this purpose. The resulting toolkit is used in the correction of the Pareto set, which is reconstructed using a combination of neural networks that include segmentation models. As a result, a model for constructing a Pareto set was created for a system of functions defined in tabular form, which allows to find a compromise when deciding on the modeling of a complex product.
- Published
- 2021
13. La segmentación en venta directa como herramienta de fidelización
- Author
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Ortega Álvarez, Ana María, Roa Fuentes, Hernán Arturo, Ortega Álvarez, Ana María, and Roa Fuentes, Hernán Arturo
- Abstract
Las organizaciones de venta directa enfrentan el problema que muchas de las personas que se afilian para vender los catálogos abandonan de manera precipitada las organizaciones, lo que implica la inversión de la mayor parte del presupuesto comercial para reclutar nuevas vendedoras. Se han ideado modelos de segmentación para clasificar a las vendedoras y poder implementar estrategias de marketing más ajustadas, esto hasta ahora no ha sido suficiente; este trabajo reúne testimonios de expertos y construye una propuesta de segmentación de acuerdo con sus opiniones.
- Published
- 2021
14. Enhanced lung image segmentation using deep learning
- Author
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Shilpa Gite, Abhinav Mishra, and Ketan Kotecha
- Subjects
Lung segmentation ,ComputingMethodologies_PATTERNRECOGNITION ,Segmentation models ,Artificial Intelligence ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Data preprocessing ,Deep learning ,TB dataset ,Software ,S.I. : Neural Computing for IOT based Intelligent Healthcare Systems - Abstract
With the advances in technology, assistive medical systems are emerging with rapid growth and helping healthcare professionals. The proactive diagnosis of diseases with artificial intelligence (AI) and its aligned technologies has been an exciting research area in the last decade. Doctors usually detect tuberculosis (TB) by checking the lungs’ X-rays. Classification using deep learning algorithms is successfully able to achieve accuracy almost similar to a doctor in detecting TB. It is found that the probability of detecting TB increases if classification algorithms are implemented on segmented lungs instead of the whole X-ray. The paper’s novelty lies in detailed analysis and discussion of U-Net + + results and implementation of U-Net + + in lung segmentation using X-ray. A thorough comparison of U-Net + + with three other benchmark segmentation architectures and segmentation in diagnosing TB or other pulmonary lung diseases is also made in this paper. To the best of our knowledge, no prior research tried to implement U-Net + + for lung segmentation. Most of the papers did not even use segmentation before classification, which causes data leakage. Very few used segmentations before classification, but they only used U-Net, which U-Net + + can easily replace because accuracy and mean_iou of U-Net + + are greater than U-Net accuracy and mean_iou , discussed in results, which can minimize data leakage. The authors achieved more than 98% lung segmentation accuracy and mean_iou 0.95 using U-Net + + , and the efficacy of such comparative analysis is validated.
- Published
- 2021
15. La segmentación en venta directa como herramienta de fidelización
- Author
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Roa Fuentes, Hernán Arturo and Ortega Álvarez, Ana María
- Subjects
Venta directa ,Loyalty ,Segmentation models ,Fidelización de clientes ,Direct sales ,SERVICIO AL CLIENTE ,VENTAS ,CANALES DE COMERCIALIZACIÓN ,MERCADEO - INVESTIGACIONES ,Modelos de segmentación ,RELACIONES CON LOS CLIENTES - Abstract
Las organizaciones de venta directa enfrentan el problema que muchas de las personas que se afilian para vender los catálogos abandonan de manera precipitada las organizaciones, lo que implica la inversión de la mayor parte del presupuesto comercial para reclutar nuevas vendedoras. Se han ideado modelos de segmentación para clasificar a las vendedoras y poder implementar estrategias de marketing más ajustadas, esto hasta ahora no ha sido suficiente; este trabajo reúne testimonios de expertos y construye una propuesta de segmentación de acuerdo con sus opiniones.
- Published
- 2021
16. Approche système d'optimisation d'un prédistorteur numérique avec une complexité réduite pour la linéarisation des amplificateurs de puissance RF
- Author
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Kantana, Chouaib and STAR, ABES
- Subjects
Power Amplifier ,Digital Predistortion ,Linearization technique ,Segmentation models ,Linéarisation ,Modeles avec segmentation ,Amplificateur de puissance ,Prédistortion numérique ,[SPI.TRON] Engineering Sciences [physics]/Electronics - Abstract
This Ph.D. work contributes to the digital predistortion linearization technique of power amplifiers. Power Amplifier is one of the most critical elements of radiocommunication systems, which exhibits static nonlinearities and nonlinear memory effects. Achieving a good trade-off between the linearity of the power amplifier and its efficiency is becoming more crucial.Digital predistortion is a powerful linearization technique that aims to compensate for power amplifier distortions and provides linear amplification with good efficiency. The predistortion principle consists of implementing a nonlinear function, the so-called predistorter upstream of the power amplifier. The predistorter ideally has the inverse characteristics of the power amplifier. This operation allows us to consider the memory effects of the power amplifier, and in particular, the long-term memory. Several behavioral models have been used as predistorter.Most of them are classified into two families: global models derived from the Volterra series and models based on the segmentation approach. The comparative and analysis study of these models is one of the focuses of this dissertation, in which three aspects are used for comparison: linearization performance, complexity, and hardware implementation properties.By focusing on models based on the segmentation approach, this dissertation proposes an approach to design an optimal model according to a trade-off between linearization performance and model complexity.This model is used to linearize a dual-input Doherty power amplifier. A global optimization algorithm combined with a control process is proposed to enhance efficiency while maintaining a good linearity level according to a proposed adaptive cost function, Le travail de thèse présenté par ce manuscrit s'intéresse à la linéarisation des amplificateurs de puissance en utilisant la prédistorsion numérique. L'amplificateur de puissance est l'un des modules les plus critiques des équipements de communication radio qui présente des non-linéarités statiques ainsi que des effets de mémoire. Il devient de plus en plus crucial de réaliser un compromis entre la linéarité et le rendement énergétique.La prédistorsion numérique est une technique de linéarisation efficace qui compense les distorsions dues à la non-linéarité en appliquant une déformation sur le signal d’entrée, de manière à ce que le système global réalise une amplification linéaire. Le principe de la prédistortion numérique consiste à mettre en œuvre une fonction non linéaire dite prédistorteur en amont de l'amplificateur de puissance, et qui a idéalement les caractéristiques inverses de l'amplificateur de puissance.Cette opération permet également de prendre en compte les effets mémoire, et en particulier la mémoire à long terme. Plusieurs modèles comportementaux sont proposés pour la prédistorsion qui peuvent être classés en deux catégories : les modèles globaux et les modèles par segmentation. L'étude comparative de ces modèles est l'un des axes de travail traité par cette thèse, dont la comparaison repose sur trois aspects qui sont soulignés : les performances de linéarisation, la complexité et les propriétés de l'implémentation matérielle. En se concentrant sur les modèles basés sur l'approche par segmentation, un algorithme est proposé pour concevoir un modèle optimal en satisfaisant un bon compromis entre les performances de linéarisation et la complexité du modèle. Ce modèle est utilisé pour linéariser un amplificateur de puissance Doherty à double entrée pour lequel un algorithme d'optimisation globale associé à un processus de contrôle est proposé pour améliorer le rendement tout en conservant un bon niveau de linéarité selon une fonction de coût adaptative
- Published
- 2021
17. EnMcGAN: Adversarial Ensemble Learning for 3D Complete Renal Structures Segmentation
- Author
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Xiaoming Qi, Rongjun Ge, Yang Chen, Huazhong Shu, Guanyu Yang, Shuo Li, Jean-Louis Coatrieux, Youyong Kong, Yuting He, Southeast University, Centre de Recherche en Information Biomédicale sino-français (CRIBS), Université de Rennes (UR)-Southeast University [Jiangsu]-Institut National de la Santé et de la Recherche Médicale (INSERM), Laboratoire Traitement du Signal et de l'Image (LTSI), Université de Rennes (UR)-Institut National de la Santé et de la Recherche Médicale (INSERM), University of Western Ontario (UWO), 2242019K3DN08National Natural Science Foundation of China, NSFC: 31571001, 31800825, 61828101Southeast University, SEU, Feragen A.Sommer S.Schnabel J.Nielsen M., Jonchère, Laurent, Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Southeast University [Jiangsu]-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)
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FOS: Computer and information sciences ,Computer science ,Computer Vision and Pattern Recognition (cs.CV) ,Feature extraction ,Computer Science - Computer Vision and Pattern Recognition ,Inference ,Diseases ,Anatomical variations ,030218 nuclear medicine & medical imaging ,Image (mathematics) ,Segmented structure ,03 medical and health sciences ,Shape conditions ,0302 clinical medicine ,Sørensen–Dice coefficient ,Market segmentation ,Ensemble learning ,FOS: Electrical engineering, electronic engineering, information engineering ,Partial nephrectomy ,Segmentation ,[SDV.IB] Life Sciences [q-bio]/Bioengineering ,Image segmentation ,business.industry ,Segmentation quality ,Image and Video Processing (eess.IV) ,Contrast (statistics) ,Quality control ,Pattern recognition ,Electrical Engineering and Systems Science - Image and Video Processing ,Segmentation models ,Segmentation accuracy ,Image enhancement ,[SDV.IB]Life Sciences [q-bio]/Bioengineering ,Artificial intelligence ,Medical imaging ,business ,030217 neurology & neurosurgery - Abstract
International audience; 3D complete renal structures (CRS) segmentation targets on segmenting the kidneys, tumors, renal arteries and veins in one inference. Once successful, it will provide preoperative plans and intraoperative guidance for laparoscopic partial nephrectomy(LPN), playing a key role in the renal cancer treatment. However, no success has been reported in 3D CRS segmentation due to the complex shapes of renal structures, low contrast and large anatomical variation. In this study, we utilize the adversarial ensemble learning and propose Ensemble Multi-condition GAN (EnMcGAN) for 3D CRS segmentation for the first time. Its contribution is three-fold. 1) Inspired by windowing [4], we propose the multi-windowing committee which divides CTA image into multiple narrow windows with different window centers and widths enhancing the contrast for salient boundaries and soft tissues. And then, it builds an ensemble segmentation model on these narrow windows to fuse the segmentation superiorities and improve whole segmentation quality. 2) We propose the multi-condition GAN which equips the segmentation model with multiple discriminators to encourage the segmented structures meeting their real shape conditions, thus improving the shape feature extraction ability. 3) We propose the adversarial weighted ensemble module which uses the trained discriminators to evaluate the quality of segmented structures, and normalizes these evaluation scores for the ensemble weights directed at the input image, thus enhancing the ensemble results. 122 patients are enrolled in this study and the mean Dice coefficient of the renal structures achieves 84.6%. Extensive experiments with promising results on renal structures reveal powerful segmentation accuracy and great clinical significance in renal cancer treatment. © 2021, Springer Nature Switzerland AG.
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- 2021
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18. Segmentation of the millipede trunk as suggested by a homeotic mutant with six extra pairs of gonopods.
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Akkari, Nesrine, Enghoff, Henrik, and Minelli, Alessandro
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ANIMAL ecology , *TRANSCRIPTION factors , *GONAPODYACEAE , *MILLIPEDES , *ANIMAL behavior ,GEOGRAPHICAL distribution of millipedes - Abstract
Background The mismatch between dorsal and ventral trunk features along the millipede trunk was long a subject of controversy, largely resting on alternative interpretations of segmentation. Most models of arthropod segmentation presuppose a strict sequential antero-posterior specification of trunk segments, whereas alternative models involve the early delineation of a limited number of 'primary segments' followed by their sequential stereotypic subdivision into 2n definitive segments. The 'primary segments' should be intended as units identified by molecular markers, rather than as overt morphological entities. Two predictions were suggested to test the plausibility of multiple-duplication models of segmentation: first, a specific pattern of evolvability of segment number in those arthropod clades in which, segment number is not fixed (e.g., epimorphic centipedes and millipedes); second, the occurrence of discrete multisegmental patterns due to early, initially contiguous positional markers. Results We describe a unique case of a homeotic millipede with 6 extra pairs of ectopic gonopods replacing walking legs on rings 8 (leg-pairs 10-11), 15 (leg-pairs 24-25) and 16 (leg-pairs 26- 27); we discuss the segmental distribution of these appendages in the framework of alternative models of segmentation and present an interpretation of the origin of the distribution of the additional gonopods. The anterior set of contiguous gonopods (those normally occurring on ring 7 plus the first set of ectopic ones on ring 8) is reiterated by the posterior set (on rings 15-16) after exactly 16 leg positions along the AP body axis. This suggests that a body section including 16 leg pairs could be a module deriving from 4 cycles of regular binary splitting of an embryonic 'primary segment.' Conclusions A very likely early determination of the sites of the future metamorphosis of walking legs into gonopods and a segmentation process according to the multiplicative model may provide a detailed explanation for the distribution of the extra gonopods in the homeotic specimen. The hypothesized steps of segmentation are similar in both a normal and the studied homeotic specimen. The difference between them would consist in the size of the embryonic trunk region endowed with a positional marker whose presence will later determine the replacement of walking legs by gonopods. [ABSTRACT FROM AUTHOR]
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- 2014
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19. Spatiotemporal detection of maritime targets using neural networks
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Pruim, R.H.R., Opbroek, A. van, Kruithof, M.C., Hollander, R.J.M. den, Baan, J., Broek, S.P. van den, Stap, N. van der, and Dijk, J.
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Image segmentation ,Naval vessels ,Learning systems ,Object detection ,Tracking ,Electro-optical ,Deep learning ,Target tracking ,Network security ,Spatio-temporal learning ,Electro optical ,Maritime ,Surface discharges ,Eye movements ,Adjustable parameters ,Segmentation ,Detection and tracking ,Segmentation models ,Machine learning ,Automatic Detection ,Situation awareness ,Infrared ,Infrared radiation - Abstract
Automatic detection and tracking of maritime targets in imagery can greatly increase situation awareness on naval vessels. Various methods for detection and tracking have been proposed so far, both for reasoning as well as for learning approaches. Learning approaches have the promise to outperform reasoning approaches. They typically detect targets in a single frame, followed by a tracking step in order to follow targets over time. However, such approaches are sub-optimal for detection of small or distant objects, because these are hard to distinguish in single frames. We propose a new spatiotemporal learning approach that detects targets directly from a series of frames. This new method is based on a deep learning segmentation model and is now applied to temporal input data. This way, targets are detected based not only on appearance in a single frame, but also on their movement over time. Detection hereby becomes more similar to how it is performed by the human eye: by focusing on structures that move differently compared to their surroundings. The performance of the proposed method is compared to both ground-Truth detections and detections of a contrast-based detector that detects targets per frame. We investigate the performance on a variety of infrared video datasets, recorded with static and moving cameras, different types of targets, and different scenes. We show that spatiotemporal detection overall obtains similar to slightly better performance on detection of small objects compared to the state-of-The-Art frame-wise detection method, while generalizing better with fewer adjustable parameters, and better clutter reduction. © 2019 SPIE.
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- 2019
20. Spatiotemporal detection of maritime targets using neural networks
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Image segmentation ,Naval vessels ,Learning systems ,Object detection ,Tracking ,Electro-optical ,Deep learning ,Target tracking ,Network security ,Spatio-temporal learning ,Electro optical ,Maritime ,Surface discharges ,Eye movements ,Adjustable parameters ,Segmentation ,Detection and tracking ,Segmentation models ,Machine learning ,Automatic Detection ,Situation awareness ,Infrared ,Infrared radiation - Abstract
Automatic detection and tracking of maritime targets in imagery can greatly increase situation awareness on naval vessels. Various methods for detection and tracking have been proposed so far, both for reasoning as well as for learning approaches. Learning approaches have the promise to outperform reasoning approaches. They typically detect targets in a single frame, followed by a tracking step in order to follow targets over time. However, such approaches are sub-optimal for detection of small or distant objects, because these are hard to distinguish in single frames. We propose a new spatiotemporal learning approach that detects targets directly from a series of frames. This new method is based on a deep learning segmentation model and is now applied to temporal input data. This way, targets are detected based not only on appearance in a single frame, but also on their movement over time. Detection hereby becomes more similar to how it is performed by the human eye: by focusing on structures that move differently compared to their surroundings. The performance of the proposed method is compared to both ground-Truth detections and detections of a contrast-based detector that detects targets per frame. We investigate the performance on a variety of infrared video datasets, recorded with static and moving cameras, different types of targets, and different scenes. We show that spatiotemporal detection overall obtains similar to slightly better performance on detection of small objects compared to the state-of-The-Art frame-wise detection method, while generalizing better with fewer adjustable parameters, and better clutter reduction. © 2019 SPIE.
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- 2019
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