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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Non-contact Methods for Detecting Hot-mix Asphalt Nonuniformity

de León Izeppi, Edgar 06 November 2006 (has links)
Segregation, or non-uniformity, in Hot Mix Asphalt (HMA) induces accelerated pavement distress(es) that can reduce a pavement's service life up to 50%. Quality Assurance procedures should detect and quantify the presence of this problem in newly constructed pavements. Current practices are usually based on visual inspections that identify non-uniform surface texture areas. An automatic process that reduces subjectivity would improve the quality-assurance procedures of HMA pavements. Virginia has undertaken a focused research effort to improve the uniformity of hot-mix asphalt (HMA) pavements. A method using a dynamic (laser-based) surface macrotexture instrument showed great promise, but it revealed that it may actually miss significant segregated areas because they only measure very thin longitudinal lines. The main objective of this research is to develop a non-contact system for the detection of segregated HMA areas and for the identification of the locations of these areas along a road for HMA quality assurance purposes. The developed system uses relatively low cost components and innovative image processing and analysis software. It computes the gray level co-occurrence matrix (GLCM) of images of newly constructed pavements to find various parameters that are commonly used in visual texture analysis. Using principal component analysis to integrate multivariable data into a single classifier, Hotelling's T2 statistic, the system then creates a list of the location of possible nonuniformities that require closer inspection. Field evaluations of the system at the Virginia Smart Road proved that it is capable of discriminating between different pavement surfaces. Verification of the system was conducted through a series of field tests to evaluate the uniformity of newly constructed pavements. A total of 18 continuous road segments of recently paved roads were tested and analyzed with the system. Tables and plots to be used by inspection personnel in the field were developed. The results of these field tests confirmed the capability of the system to detect potential nonuniformities of recently completed pavements. The system proved its potential as a useful tool in the final inspection process. / Ph. D.
12

Ανάλυση αλγορίθμων εξισορρόπησης χρώματος σε ψηφιακές εικόνες

Δογάνης, Γεώργιος 10 March 2014 (has links)
Η υπολογιστική εξισορρόπηση χρώματος είναι ένα βασικό προαπαιτούμενο για πολλές εφαρμογές όρασης μηχανών. Στην εργασία αυτή παρουσιάζονται πολλές πρόσφατες εξελίξεις και οι τελευταίες μέθοδοι εξισορρόπησης χρώματος. Προτείνονται επίσης διαφορετικά κριτήρια για την εκτίμηση των προσεγγίσεων αυτών. Επιχειρείται μια ταξινόμηση των μεθόδων αυτών και αυτές χωρίζονται σε τρεις ομάδες: τις στατικές μεθόδους, τις μεθόδους βασισμένες στο χρωματικό εύρος (gamut-based) και τις μεθόδους βασισμένες στην εκπαίδευση (learning-based). Ακόμη, συζητείται η πειραματική διάταξη συμπεριλαμβανομένης μιας επισκόπησης των δημόσια διαθέσιμων συνόλων δεδομένων εικόνας. Τέλος, γίνεται μια αξιολόγηση των μεθόδων που θεωρούνται αιχμής με βάση δύο σύνολα δεδομένων. / Computational color constancy is a fundamental prerequisite for many computer vision applications. This dissertation presents a survey of many recent developments and state-of-the- art methods. Several criteria are proposed that are used to assess the approaches. A taxonomy of existing algorithms is proposed and methods are separated in three groups: static methods, gamut-based methods and learning-based methods. Further, the experimental setup is discussed including an overview of publicly available data sets. Finally, various freely available methods, of which some are considered to be state-of-the-art, are evaluated on two data sets.
13

Identificação de pragas na agricultura utilizando APIs de visão computacional

Vilas Boas, Lenilson Lemos 26 November 2018 (has links)
Submitted by Filipe dos Santos (fsantos@pucsp.br) on 2018-12-14T11:45:48Z No. of bitstreams: 1 Lenilson Lemos Vilas Boas.pdf: 4297593 bytes, checksum: 1aa03b41410e014c8021095ee73b5e7b (MD5) / Made available in DSpace on 2018-12-14T11:45:48Z (GMT). No. of bitstreams: 1 Lenilson Lemos Vilas Boas.pdf: 4297593 bytes, checksum: 1aa03b41410e014c8021095ee73b5e7b (MD5) Previous issue date: 2018-11-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Systems that use Computer Vision Application Program Interfaces (APIs) can learn and identify patterns and thus perform associations to retrieve additional data. They are able to obtain results much faster than any human agent is. The study uses three computational vision APIs and evaluates their application in the identification of four plant leave diseases. Based on a corpus of fifty images, the API training was conducted in two stages, the first with thirty images and the second training with twenty more images. After the two trainings, the results of the diseases were collected for each API studied, which made it possible to evaluate the identification capacity and its evolution of learning after each training. The results corroborated the hypothesis. They gave evidence of the feasibility of identification of plant leaf diseases by means of computer vision APIs / Sistemas que utilizam APIs (Interfaces de Programação de Aplicação) de visão computacional têm a capacidade de aprender e identificar padrões, e assim realizar associações com outros resultados, sendo capaz de apresentar resultados mais rápidos do que uma pessoa. O trabalho identificou três APIs de visão computacional e avaliou sua aplicação na identificação de doenças em folhas de plantas, comparando os resultados de quatro diferentes doenças de plantas. Os treinamentos das APIs foram realizados em duas etapas, sendo o primeiro treinamento com uma quantidade de imagens e o segundo treinamento adicionando mais imagens. Após os dois treinamentos foram coletados os resultados das doenças para cada API estudada, sendo possível avaliar a capacidade de identificação e sua evolução de aprendizado após cada um dos treinamentos. Os resultados obtidos corroboram as expectativas, apontando para a viabilidade de identificação de doenças em folhas de plantas através de APIs de visão computacional
14

Enhancing the value of solid residues from wheat biorefineries using Solid State Bioprocessing

López Gómez, José Pablo January 2017 (has links)
The maximum potential of biorefineries cannot be achieved without the valorisation of their residues. The two main residues from wheat biorefineries, bran and wet distiller's grains and solubles (WDGS), have a projected production of 7 and 3 million tonnes/year respectively by 2025 just in the European Union. These residues can be mixed to form moist animal feed. However, the product can undergo growth of contaminating fungi. This bio-deterioration causes significant losses and represents a hazard for the animals. Currently, commercial preservatives (from the petrochemical industry) are added to prevent bio-deterioration but these add to the production cost. The research reported in this thesis was focused on the utilisation of solid state bioprocessing (SSB) to prevent the bio-deterioration of the moist feed. The method is based on the inhibition of contaminating fungi by an edible fungus, R. oryzae, considered safe for animal consumption which is a lactic acid producer. This fungus is known to produce very dense mycelia causing significant oxygen transfer limitations and this, together with the reduction in pH and substrate available for contaminating fungi, was explored as a potential mechanism to bio-preserve the moist feed. SSB, has been targeted as a key technology for the treatment of agro-industrial solid residues. However, the measurement of parameters in SSB is very complicated, hampering the development of the technology. Consequently, methods for the measurement of pH and growth in SSB were also studied. The measurement of pH is normally performed in extract solutions but, although widely used, the method has not been standardised. There are many extraction variables, such as contact time, type of solids and solvent, solid:water ratio and agitation velocity, involved in the measurement. Experiments revealed that changes in the extraction conditions affect pH readings. The degree of impact depends upon the variable but results presented in this thesis clearly highlight the importance of providing a precise and comprehensive report of the extraction conditions. For the estimation of growth, a method based on digital imaging analysis (DIA) was developed in this work. DIA is a non-destructive, quick and simple method, which uses computational analysis of digital images to measure areas and colour changes on a surface. The technique provided data that allowed an objective comparison of fungal colonies on plates, making it of higher quality than simple visual evaluation. It was determined that C*Traffordgold, the model moist feed used in this research, has starch and moisture contents of 10% and 50% respectively. Bio-deterioration is caused by indigenous organisms in the bran and is observable after only 2 days of incubation at 20°C. R. oryzae was able to bio-preserve the material for at least a month. This is a very promising result since preservative treated C*Traffordgold shows considerable bio-deterioration after just 2 weeks. DIA was used for the estimation of R. oryzae growth at different temperatures, moisture contents and inoculum sizes. The fungus was able to grow at temperatures between 15° and 37°C, with optimum growth at 30°C. An increase in the moisture content resulted in faster growth of the fungus and it was determined that a minimum inoculum size of 103 spores/gC*Traffordgold is necessary to avoid bio-deterioration. The bio-preservation is a result of the reduction of substrate and oxygen available for contaminating microorganisms. Studies revealed that lactic acid does not inhibit growth of contaminating fungi even at pH 4. On the other hand, R. oryzae showed radial growth rates up to 6 times faster than those from contaminating cultures. The fungus is able to surround the competitor colony and 'enclose' it. The formation of a fungal barrier limits the oxygen available for the undesired colony, hampering its growth. It was estimated that by implementing the bio-preservation method a wheat biorefinery producing 180,000 tpa of moist feed could save circa 500,000 USD per annum. Integration of residue processing in biorefineries is necessary to make them sustainable. The application of SSB for bio-preservation could enhance the overall value of wheat biorefineries and simultaneously reduce dependency on the petrochemical industry.
15

Corneal topography and the morphology of the palpebral fissure

Read, Scott A. January 2006 (has links)
The notion that forces from the eyelids can alter the shape of the cornea has been proposed for many years. In recent times, there has been a marked improvement in our ability to measure and define the corneal shape, allowing subtle changes in the cornea to be measured. These improvements have led to the findings that pressure from the eyelids can cause alterations in corneal shape following everyday visual tasks such as reading. There are also theories to suggest that pressure from the eyelids may be involved in the aetiology of corneal astigmatism. In this program of research, a series of experiments were undertaken to investigate the influence of the eyelids on the shape of the cornea. In the first experiment, an investigation into the diurnal variation of corneal shape was carried out by measuring corneal topography at three different times (approximately 9 am, 1 pm and 5 pm) during the day over three days of the week (Monday, Tuesday and Friday). Highly significant diurnal changes were found to occur in the corneal topography of 15 of the 17 subjects. This change typically consisted of horizontal bands of distortion in the superior, and to a lesser extent, inferior cornea, increasing throughout the day (and returning to baseline the next morning). These changes appeared to be related to forces from the eyelids on the anterior cornea. Some changes were also found in corneal astigmatism. Corneal astigmatism power vector J0 (astigmatism 90/180°) was found to increase slightly over the course of the week. Whilst the changes in astigmatism were small in magnitude, this result leaves open the possibility that pressure from the eyelid may cause changes in corneal astigmatism. If pressure from the eyelids is involved in the aetiology of corneal astigmatism, then one may expect associations to exist between certain characteristics of the eyelids and corneal shape. An experiment was then undertaken to explore these possible associations. We defined the average morphology of the palpebral fissure in different angles of vertical gaze for 100 young normal subjects. This was achieved through analysis of digital images that were captured in primary gaze, 20° downgaze and 40° downgaze. Parameters defining the size, position, angle and contour of the eyelids were determined. Highly significant changes were found to occur in the palpebral fissure with downward gaze. The palpebral aperture narrows in downward gaze, and the angle of the eyelids changes from being slightly upward slanted in primary gaze, to being slightly downward slanted in downward gaze. The eyelid margin contour also flattens significantly in downward gaze. The average topography of the central and peripheral cornea was also defined for this same population. A technique was used that allowed the capture and subsequent combination of topography data from both the central and the peripheral cornea. The use of this technique provided a large corneal topography map, with data extending close to the limbus for each subject. Marked flattening was found to occur in the peripheral cornea and a conic section was found to be a poor descriptor of corneal contour in the periphery (i.e. greater than 6 mm diameter). Corneal astigmatism was also found on average to reduce in the periphery. However a number of distinct patterns of peripheral corneal astigmatism were noted in the population. Corneal astigmatism in the peripheral cornea was either found to remain stable (59% of subjects), increase (10% of subjects) or reduce (31% of subjects) in magnitude in comparison to the amount of central corneal astigmatism. We also investigated associations between the parameters defining the palpebral fissure and parameters describing corneal shape in this population of subjects. A number of highly significant associations were found between the morphology of the palpebral fissure in primary gaze and the shape of the cornea. A general tendency was found for subjects with wider horizontal palpebral fissure widths to exhibit larger corneas and also flatter central corneal powers. There were also highly significant associations found between the angle of the eyelids and the axis of corneal astigmatism, but not the magnitude of corneal astigmatism. The associations found between corneal astigmatism and palpebral fissure morphology is further evidence supporting the hypothesis that pressure from the eyelids is involved in the aetiology of corneal astigmatism. The results of these investigations have shown that corneal changes as a result of eyelid forces occur in the majority of young subjects tested over the course of a normal working day. The average morphology of the palpebral fissure and topography of the central and peripheral cornea has also been defined in detail for a large population of young subjects. Significant associations were found between corneal astigmatism and the morphology of the palpebral fissure. Whilst these results support a model of corneal astigmatism development based on eyelid morphology, they do not prove causation. Further research including measurement of eyelid pressure and corneal rigidity may aid in understanding the exact aetiology of the magnitude and axis of corneal astigmatism.
16

Metadados: a recuperação de imagens digitais baseada em conteúdo / The recovery of digital images based on content

Santos, Júllia Mendes Pestana dos [UNESP] 18 June 2018 (has links)
Submitted by Júllia Mendes Pestana Dos Santos (julliapestan@hotmail.com) on 2018-07-16T01:31:34Z No. of bitstreams: 1 DISSERTAÇÃO FINAL.output.pdf: 3255322 bytes, checksum: 56ad1a6301c009bcfaf0bd6c5ef7b0f4 (MD5) / Approved for entry into archive by Telma Jaqueline Dias Silveira null (telmasbl@marilia.unesp.br) on 2018-07-16T19:46:08Z (GMT) No. of bitstreams: 1 santos_jmp_me_mar.pdf: 3255322 bytes, checksum: 56ad1a6301c009bcfaf0bd6c5ef7b0f4 (MD5) / Made available in DSpace on 2018-07-16T19:46:08Z (GMT). No. of bitstreams: 1 santos_jmp_me_mar.pdf: 3255322 bytes, checksum: 56ad1a6301c009bcfaf0bd6c5ef7b0f4 (MD5) Previous issue date: 2018-06-18 / A questão da indexação e recuperação de imagens tem atraído a atenção de novos interessados, tanto os preocupados com o conteúdo informacional, quanto os interessados em desenvolver formas automatizadas de descrição e acesso ao conteúdo imagético. No contexto das imagens digitais, para que elas se tornem recursos disponíveis, recuperáveis e acessíveis é necessário um desenvolvimento de processos para construção de representações. Um impulso na revolução das imagens digitais foi dado pela expansão da utilização dos computadores, onde surgiram técnicas para captura, armazenamento, processamento e transmissão das mesmas. Neste sentido, o objetivo do trabalho foi discutir o processo de indexação e recuperação de imagens no contexto de sistemas informáticos. Abordamos tanto a indexação quanto a recuperação de imagens fotográficas, visando melhorar a precisão de recuperação desses documentos em sistemas de informação. O uso de metadados neste contexto é significativo, pois o funcionamento da web está ligado à facilidade de recuperação de dados. E assim, os sistemas de Recuperação da Imagem Baseado em Conteúdo (CBIR) evidenciam a necessidade da introdução de novos atributos/características, como a utilização de cor, formas, texturas. Mas somente essas propriedades não solucionam o problema da organização e recuperação de conteúdo imagético e, portanto nesse contexto a criação de metadados aos elementos básicos da linguagem visual: ponto, linha, forma, direção, tom, cor, textura, escala, dimensão e movimento para construção e recuperação da imagem serão a proposta e análise dessa pesquisa. E os resultados apontam que o software Sepiades por ser um software livre, ainda que seja para descrição de imagens, torna-se mais acessível e compatível e seus elementos são passíveis de miscigenação, sendo uma boa solução. Conclui-se que uma participação significativa dos indexadores no desenvolvimento de softwares para organização e recuperação imagética é de extrema importância e contribuição para área da Ciência da Informação (CI) e Computação. Desse modo destacamos a importância de estudos e pesquisas que tenham como objetivo a Recuperação de Imagens e os diversos mecanismos de busca da informação, bem como, conhecer as tecnologias existentes e a sua utilização. / The issue of indexing and retrieval of images has attracted the attention of new stakeholders, both those concerned with the information content of the images and those interested in developing automated forms of description and access to images. In the context of digital images, for them to become available, retrievable and accessible resources, a process development is necessary for the construction of representations. An impulse in the digital imaging revolution was the expansion of computer use, where techniques for capturing, storing, processing and transmitting images emerged. In this sense, the objective of the work is the process of indexing and retrieving images in the context of computer systems. We address both indexing and retrieval of photographic images, aiming to improve the accuracy of image retrieval in information systems. The use of metadata in this context will be significant, as the operation of the web is linked to the ease of data recovery. Thus, Content Based Image Retrieval (CBIR) systems highlight the need to introduce new attributes / characteristics, such as the use of color, shapes, textures. But only these properties do not solve the problem of image organization and retrieval, and in this context, the creation of metadata to the basic elements of visual language: point, line, shape, direction, tone, color, texture, scale, dimension and motion for construction and image recovery will be the proposal and analysis of this research. And the results show that the software Sepiades, because it is a free software, although it is for image description, it becomes more accessible and compatible and its elements are susceptible of miscegenation, being a good solution. It is concluded that a significant participation of indexers in the development of software for organization and image recovery is of extreme importance and contribution to the area of Information Science (CI) and Computing. In this way, we highlight the importance of studies and research that aim at Image Retrieval and in the various information search mechanisms, as well as to know the existing technologies and their use.
17

ARCHIVING THE DIGITAL IMAGE: TODAY'S BEST PRACTICES OF FILE PREPARATION

Frank, Wiewandt Edward 07 November 2005 (has links)
No description available.
18

BIOCHEMICAL AND COLORIMETRIC STUDY OF FLOWER COLOR IN PHLOX SPECIES

Bohorquez-Restrepo, Andres 19 May 2015 (has links)
No description available.
19

<i>ASSESSMENT OF THE SKIN CONDITION OF HEALTH CARE WORKERS USING DIGITAL IMAGE PROCESSING</i>

CANNING, JENNIFER L. January 2006 (has links)
No description available.
20

Application of Machine Learning and Hyperspectral Imaging in Plant Phenomics Research

Dhakal, Kshitiz 08 March 2023 (has links)
Doctor of Philosophy / The digital imaging technology, geographical analyses tool, and computer vision (a technique that enables computers and systems to get meaningful information from images) methods can be used to extract traits-related branching pattern, canopy cover, and pod location in edamame for many plant populations in short time using less labor and resources. Using genome-wide association study, we identified several genetic markers that were associated with those traits. These markers can be used in marker-assisted selection to develop the edamame varieties that are more adaptable to mechanical harvesting and give more yield, along with understanding the physiological mechanisms for better shoot architecture traits and better yield. We used spectral signatures of different edamame at several harvesting time along with machine learning methods to identify the optimal harvest time of edamame. Hyperspectral imaging (a technique that analyzes a wide spectrum of light instead of just assigning primary colors (red, green, blue) to each pixel) when combined with computer vision and machine learning methods can be used to quantify the levels of vomitoxin (chemical that causes vomiting and feed refusal in animal and humans) for larger wheat kernel samples in a cheaper and faster way.

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