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Topological multi-contour decomposition for image analysis and image retrieval

BRUNO, Odemir Martinez; NONATO, Luis Gustavo; PAZOTI, Mario Augusto; BATISTA NETO, Joao
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
65.91%
Successful classification, information retrieval and image analysis tools are intimately related with the quality of the features employed in the process. Pixel intensities, color, texture and shape are, generally, the basis from which most of the features are Computed and used in such fields. This papers presents a novel shape-based feature extraction approach where an image is decomposed into multiple contours, and further characterized by Fourier descriptors. Unlike traditional approaches we make use of topological knowledge to generate well-defined closed contours, which are efficient signatures for image retrieval. The method has been evaluated in the CBIR context and image analysis. The results have shown that the multi-contour decomposition, as opposed to a single shape information, introduced a significant improvement in the discrimination power. (c) 2008 Elsevier B.V. All rights reserved,

Tratamento de úlceras venosas por ultra-som de baixa intensidade: avaliação por análise de imagem e imunohistoquímica; Treatment of venous ulcers by low intensity ultrasound: assessment by image analysis and immunohistochemistry

Santana, Luísiane de Ávila
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 01/11/2006 PT
Relevância na Pesquisa
65.92%
Úlceras de perna acometem as extremidades dos membros inferiores e são causadas por alguma disfunção do sistema vascular. A cicatrização das úlceras é um processo dinâmico que envolve fenômenos biológicos, bioquímicos e imunológicos. A avaliação clínica da evolução das úlceras é difícil e se baseia nas modificações teciduais como granulação, fibrina/esfácelo e reepitelização. A avaliação clínico terapêutica adequada compreende da avaliação da área das úlceras e das áreas correspondentes aos diferentes tecidos presentes nas mesmas. Inúmeras são as opções terapêuticas objetivando a cicatrização das úlceras, envolvendo os mais variados estímulos imunobiológicos, sendo importante a avaliação imunohistoquímica da evolução do tratamento. Estudos anteriores demonstraram que o ultra-som de baixa intensidade (US) estimula a reparação tecidual de úlceras de perna. Com base nestes estudos esta investigação tem o objetivo de comparar a eficácia do ultra-som de baixa intensidade (30 mW/'CM POT.2') e de curativos diários á base de sulfadiazina de prata 1% na cicatrização de úlceras venosas, com as seguintes implementações: a) modificação da técnica de antissepsia para aplicação do ultra-som no tratamento das úlceras; b) padronização da técnica de captura da imagem das úlceras; c) utilização de nova técnica de quantificação do tratamento das úlceras e dos seus tecidos (granulação e fibrina/esfácelo) usando o software livre ImageJ para quantificar a área da úlcera e dos seus tecidos; d) quantificação dos fatores de crescimento TGF-'BETA' e VEGF e da enzima iNOS nas biópsias iniciais e no 45° dia do tratamento das úlceras. Nesta investigação foram tratadas dezesseis úlceras de perna do tipo venosa no Ambulatório de Úlcera da Dermatologia do Centro Saúde Escola (CSE) - HCFMRP - USP. Elas foram divididas em dois grupos experimentais: grupo 1 (7 úlceras) em que foi utilizado tratamento com curativos diários á base de sulfadiazina de prata 1%; grupo 2 (9 úlceras) em que foi utilizado tratamento com US 3 vezes por semana seguido de curativos diários com gazes umedecidas com soro fisiológico ou vaselina...

Técnicas de mineração de dados para análise de imagens; Data mining techniques for image analysis

Consularo, Luís Augusto
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 26/09/2000 PT
Relevância na Pesquisa
65.92%
Imagens codificadas por matrizes de intensidade são tipicamente representadas por grande quantidade de dados. Embora existam inúmeras abordagens para análise de imagens, o conhecimento sobre problemas específicos é raramente considerado. Este trabalho trata sobre problemas de análises de imagens cujas soluções dependem do conhecimento sobre os dados envolvidos na aplicação específica. Para isso, utiliza técnicas de mineração de dados para modelar as respostas humanas obtidas de experimentos psicofísicos. Dois problemas de análise de imagens são apresentados: (1) a análise de formas e (2) a análise pictórica. No primeiro problema (1), formas de neurônios da retina (neurônios ganglionares de gato) são segmentadas e seus contornos submetidos a uma calibração dos parâmetros de curvatura considerando a segmentação manual de um especialista. Outros descritores, tais como esqueletos multi-escalas são explorados para eventual uso e avaliação da abordagem. No segundo problema (2), a análise pictórica de imagens de home-pages serve para avaliar critérios estéticos a partir de medidas de complexidade, contraste e textura. O sistema generaliza as respostas por um experimento psicofísico realizados com humanos. Os resultados objetivos com as duas abordagens revelaram-se promissores...

Aplicações de processamento e análise avançada de imagens para a caracterização de imagens de microscopia de força atômica; Processing and advanced image analysis applications for image characterization of atomic force microscopy

Rodrigues, Carlos Alberto
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 22/04/2003 PT
Relevância na Pesquisa
65.94%
Esta tese aborda a aplicação de técnicas avançadas de processamento e análise de imagens em problemas originais envolvendo imagens de microscopia de força atômica. Para isso, foi desenvolvida uma série de algoritmos para a caracterização e o entendimento do processo de formação de novos materiais poliméricos com perspectivas de inúmeras aplicações tecnológicas. As análises envolveram a determinação da orientação da morfologia de substratos para alinhamento de cristais líquidos, contagem e estimativa dos raios de domínios em filmes automontados POMA/PVS, análise do aumento da fotoluminescência em filmes PPV e estudos da curvatura espontânea de macromoléculas de polímeros. Dentre os algoritmos principais podemos citar a determinação da inclinação dos autovalores da matriz de covariância das coordenadas dos pontos da forma, aplicação da técnica dos máximos regionais e diagramas de Voronoi, filtros passabanda 2D através da transformada de Fourier e extração da curvatura multiescala. A implementação destes algoritmos envolveu algoritmos básicos de análise de imagens tais como esqueletização, dilatações exatas e extração do contorno de formas. A principal contribuição deste trabalho foi a implementação do software denominado SPIA (Scanning Probe Image Analysis) que possui ferramentas para análise e processamento de imagens incluindo todas as que foram utilizadas no decorrer deste trabalho além de outras ferramentas. Este software foi desenvolvido em ambiente Delphi sob o paradigma da orientação a objetos para plataformas Windows NT/9X/2000/XP. Possui uma interface amigável e semelhante a outros softwares dedicados a processamento de imagens. Todas as técnicas aplicadas foram testadas extensivamente e os resultados que corroboram sua eficiência são mostrados ao longo da tese; This thesis address the application of advanced techniques of processing and analysisof images in original problems involving images of atomic force microscopy. For this...

Digital image analysis of root distribution towards improved irrigation water and soil management: Grapevine and date palm study cases

Bassoi, Luís Henrique; Moura E Silva, José Antonio; De Alencar, Cristina Miranda; De Castro Jorge, Lúcio André; Hopmans, Jan W.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência Formato: 1829-1834
ENG
Relevância na Pesquisa
65.88%
It is presented two study cases about the approach in root analysis at field and laboratory conditions based on digital image analysis. Grapevine (Vitis vinifera L.) and date palm (Phoenix dactylifera L.) root systems were analyzed by both the monolith and trench wall method aided by digital image analysis. Correlation between root parameters and their fractional distribution over the soil profile were obtained, as well as the root diameter estimation. Results have shown the feasibility of digital image analysis for evaluation of root distribution.

A method for the digital image analysis of ceramic grains based on shape factor segmentation

De Campos, Elson; De Lucena, Émerson F.; De Melo, Francisco C.L.; De O. Hein, Luis Rogerio
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 725-730
ENG
Relevância na Pesquisa
65.91%
A very simple and robust method for ceramics grains quantitative image analysis is presented. Based on the use of optimal imaging conditions for reflective light microscopy of bulk samples, a digital image processing routine was developed for shading correction, noise suppressing and contours enhancement. Image analysis was done for grains selected according to their concavities, evaluated by perimeter ratio shape factor, to avoid consider the effects of breakouts and ghost boundaries due to ceramographic preparation limitations. As an example, the method was applied for two ceramics, to compare grain size and morphology distributions. In this case, most of artefacts introduced by ceramographic preparation could be discarded due to the use of perimeter ratio exclusion range.

Morphometric study by image analysis of Ag-stained nucleoli in thyroids bearing proliferating lesions

Abdo-Banhos, C. R.; Cordeiro, J. A.; Rosa, C. S.; Bicudo, H. E M C
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 37-43
ENG
Relevância na Pesquisa
65.9%
The Ag-NOR staining technique and image analysis were used to evaluate morphological parameters (area, perimeter and axis ratio) in nucleoli from normal thyroids and from thyroids bearing proliferating lesions (carcinomas, adenomas and hyperplasias). Regions with normal appearance located close to adenomatous and carcinomatous regions, in the thyroid of every patient, were also analyzed for comparison with the respective pathological regions and with normal thyroids. Statistical analysis of data for the nucleolar area and perimeter allowed the separation of adenomas and carcinomas from hyperplasias and normal tissue but not the two components in each of these two groups. However, if we look at the numbers, a sequence of increasing nucleolar mean areas in the order: normal, hyperplasia, adenoma and carcinoma may be observed, indicating the sequence of increasing rRNA requirements in these different kinds of cells. The axis ratio that denotes the nucleolar shape (round or oblong) did not show significant differences among tissues, suggesting that shape is not important in the characterization of these pathologies. Differences in nucleolar areas and perimeter between normal and affected regions from each patient were statistically significant for adenomas and carcinomas. When these normal regions were compared with the normal thyroids...

Evaluation epidermal p53 immunostaining by digital image analysis

Brianezi, Gabrielli; Minicucci, Eliana Maria; Marques, Mariângela Esther Alencar; Miot, Hélio Amante
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
65.98%
Digital techniques have been developed and validated to assess semiquantitatively immunohistochemical nuclear staining. Currently visual classification is the standard for qualitative nuclear evaluation. Analysis of pixels that represents the immunohistochemical labeling can be more sensitive, reproducible and objective than visual grading. This study compared two semiquantitative techniques of digital image analysis with three techniques of visual analysis imaging to estimate the p53 nuclear immunostaining. Methods: Sixty-three sun-exposed forearm-skin biopsies were photographed and submitted to three visual analyses of images: the qualitative visual evaluation method (0 to 4 +), the percentage of labeled nuclei and HSCORE. Digital image analysis was performed using ImageJ 1.45p; the density of nuclei was scored per ephitelial area (DensNU) and the pixel density was established in marked suprabasal epithelium (DensPSB). Results: Statistical significance was found in: the agreement and correlation among the visual estimates of evaluators, correlation among the median visual score of the evaluators, the HSCORE and the percentage of marked nuclei with the DensNU and DensPSB estimates. DensNU was strongly correlated to the percentage of p53-marked nuclei in the epidermis...

Automated image analysis to improve bead ingestion toxicity test counts in the protozoan Tetrahymena pyriformis

Dias, Nicolina; Amaral, A. L.; Ferreira, E. C.; Lima, Nelson
Fonte: The Society for Applied Microbiology Publicador: The Society for Applied Microbiology
Tipo: Artigo de Revista Científica
Publicado em //2003 ENG
Relevância na Pesquisa
65.93%
Prova de tipográfica (In Press).; Aims: To improve bead ingestion counts in Tetrahymena pyriformis by automated image analysis as an alternative to direct-counts. Methods and Results: Fluorescent latex beads were added to T. pyriformis cultures for ingestion tests. The number of beads ingested by 25 cells was counted directly by epifluorescence microscopy and compared with similar data from image analysis. ANOVA indicated that counts were not significantly different (P < 0.05). The image analysis particularly provided advantages in terms of speed. Conclusions: The image analysis is superior to direct beads counting in T. pyriformis particularly in terms of speed of analysis. Significance and Impact of the Study: The image analysis method is very rapid and will allow many more toxicological analyses to be undertaken with less operator error.

Development of an image analysis procedure for identifying protozoa and metazoa typical of activated sludge system

Ginoris, Y. P.; Amaral, A. L.; Nicolau, Ana; Coelho, M. A. Z.; Ferreira, E. C.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /06/2007 ENG
Relevância na Pesquisa
65.87%
A procedure for the semi-automatic identification of the main protozoa and metazoa species present in the activated sludge of wastewater treatment plants was developed. This procedure was based on both image processing and multivariable statistical methodologies, leading to the use of the image analysis morphological descriptors by discriminant analysis and neural network techniques. The image analysis programwritten in Matlab has proved to be adequate in terms of protozoa and metazoa recognition, as well as for the operating conditions assessment.; National Council of Scientific and Technological Development of Brazil (CNPq); BIEURAM III ALFA co-operation project (European Commission); Fundação para a Ciência e a Tecnologia (FCT)

Recognition of protozoa and metazoa using image analysis tools, discriminant analysis, neural networks and decision trees

Ginoris, Y. P.; Amaral, A. L.; Nicolau, Ana; Coelho, M. A. Z.; Ferreira, E. C.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /07/2007 ENG
Relevância na Pesquisa
65.87%
Protozoa and metazoa are considered good indicators of the treatment quality in activated sludge systems due to the fact that these organisms are fairly sensitive to physical, chemical and operational processes. Therefore, it is possible to establish close relationships between the predominance of certain species or groups of species and several operational parameters of the plant, such as the biotic indices, namely the Sludge Biotic Index (SBI). This procedure requires the identification, classification and enumeration of the different species, which is usually achieved manually implying both time and expertise availability. Digital image analysis combined with multivariate statistical techniques has proved to be a useful tool to classify and quantify organisms in an automatic and not subjective way. Thiswork presents a semi-automatic image analysis procedure for protozoa and metazoa recognition developed in Matlab language. The obtained morphological descriptors were analyzed using discriminant analysis, neural network and decision trees multivariable statistical techniques to identify and classify each protozoan or metazoan. The obtained procedure was quite adequate for distinguishing between the non-sessile protozoa classes and also for the metazoa classes...

Evaluation of activated sludge systems by image analysis procedures

Mesquita, D. P.; Dias, O.; Amaral, A. L.; Ferreira, E. C.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em 24/06/2008 ENG
Relevância na Pesquisa
65.93%
Biomass inspection under optical microscopy coupled to automated image analysis methodologies is, nowadays, increasingly used. Image analysis is presently considered a powerful tool to identify and quantify biomass morphological and physiological changes. In this work, an image analysis program was developed in Matlab environment, allowing the identification and characterization of microbial aggregates and protruding filaments in six different wastewater treatment plants. The results showed that the developed image analysis methodology proved to be a feasible method for a continuous monitoring of the activated sludge contents both in terms of aggregated biomass and filamentous bacteria, comparing the results with operating parameters. Furthermore, the results obtained during the monitoring period indicate that automated image analysis can help clarifying the nature of the events within the aeration tanks when the system is submitted to disturbances.; Fundação para a Ciência e Tecnologia (FCT) - bolsa doutoramento SFRH/BD/32329/2006, projecto POCI/AMB/57069/2004; Empresa de Águas, Efluentes e Resíduos de Braga (AGERE

Correlation between sludge settling ability and image analysis information using partial least squares

Mesquita, D. P.; Dias, O.; Dias, A. M. A.; Amaral, A. L.; Ferreira, E. C.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica
Publicado em /05/2009 ENG
Relevância na Pesquisa
65.9%
In the last years there has been an increase on the research of the activated sludge processes, and mainly on the solid–liquid separation stage, considered of critical importance, due to the different problems that may arise affecting the compaction and the settling of the sludge. Furthermore, image analysis procedures are, nowadays considered to be an adequate method to characterize both aggregated and filamentous bacteria, and increasingly used to monitor bulking events in pilot plants. As a result of that, in this work, image analysis routines were developed in Matlab environment, allowing the identification and characterization of microbial aggregates and protruding filaments. Moreover, the large amount of activated sludge data collected with the image analysis implementation can be subsequently treated by multivariate statistical procedures such as PLS. In the current work the implementation of image analysis and PLS techniques has shown to provide important information for better understanding the behavior of activated sludge processes, and to predict, at some extent, the sludge volume index. As a matter of fact, the obtained results allowed explaining the strong relationships between the sludge settling properties and the free filamentous bacteria contents...

Monitoring filamentous bulking and pin-point flocs in a lab-scale activated sludge system using image analysis

Mesquita, D. P.; Amaral, A. L.; Ferreira, E. C.
Fonte: Elsevier Publicador: Elsevier
Tipo: Conferência ou Objeto de Conferência
Publicado em /04/2010 ENG
Relevância na Pesquisa
65.96%
Activated sludge processes are the most frequently used techniques regarding biological wastewater treatment. However, depending on the process operation conditions, several malfunctions could take place, in which filamentous bulking and deflocculation processes, such as pin-point flocs, are the most common problems, causing the sludge settling ability decrease and effluent quality deterioration. Bright field Image analysis is nowadays considered a powerful tool to quantitatively characterize aggregated and filamentous bacteria. Furthermore, the use of epifluorescent staining techniques, coupled to image analysis, presents a promising method to determine bacteria gram nature and viability. Encouraged by the success of image analysis procedures over the last years, the present work studied a lab-scale activated sludge system, under operation conditions causing filamentous bulking and pin-point flocs phenomena. Sludge settling ability and turbidity values were measured verifying the nature of the settling problem. COD contents, as well as nitrogen contents, in terms of N-NH4+, N-NO3- and N-NO2-, were surveyed in the feeding effluent, reactor bulk and settler. Regarding the biomass characterization, four major morphological descriptors groups were studied...

Development of image analysis methodologies to quantify intracellular PHA, polyphosphate and glycogen within wastewater treatment plants

Amaral, A. L.; Leal, C. S.; Mesquita, D. P.; Cunha, J. R.; Oehmen, A.; Reis, M. A. M.; Ferreira, E. C.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em /01/2013 ENG
Relevância na Pesquisa
65.93%
In wastewater treatment plants (WWTP), enhanced biological phosphorus removal (EBPR) processes are performed by mixed cultures containing polyphosphate (PAO) and glycogen accumulating organisms (GAO). In these processes, it is of crucial importance to monitor the intracellular metabolism, namely glycogen, polyhydroxyalkanoates (PHA) and polyphosphate (polyP) inclusions, to determine its efficiency. However, traditional monitoring, carried out through off-line chemical analyses, is laborious and time-consuming. Therefore, there is a clear need to develop new techniques to promptly quantify these intracellular polymers, with image analysis emerging as a promising tool. The use of staining methodologies with specific fluorescent dyes is widespread in EBPR research, including Nile blue for PHA and DAPI for polyP. Although rarely applied in EBPR studies, Aniline blue is a fluorescent stain that can be used for glycogen determination. Furthermore, these fluorescent stains have generally been employed for qualitative rather than quantitative analysis. Therefore, this study aim focused on developing fluorescence-based staining methodologies for glycogen, and on acquisition, processing and image analysis procedures for PHA, polyP and glycogen. Image analysis data was then correlated with traditional analytical data by multivariable statistics. Regarding the determination of the glycogen intracellular concentration...

Image analysis for automatic characterization of polyhydroxyalcanoates granules

Mesquita, D. P.; Selvaggio, Gianluca; Cunha, J. R.; Leal, Cristiano S.; Amaral, A. L.; Ferreira, E. C.
Fonte: Springer; Springer Verlag Publicador: Springer; Springer Verlag
Tipo: Artigo de Revista Científica
Publicado em //2013 ENG
Relevância na Pesquisa
65.91%
A new monitoring approach for polyhydroxyalcanoates (PHA) granules identification and characterization based on image analysis procedures is proposed. PHA granules were analyzed by Sudan Black B (SBB) staining in an enhanced biological phosphorus removal (EBPR) system. Color images captured on an optical microscope were analyzed through quantitative image analysis. The distribution of PHA granules was estimated by determination of the proportion of blue-black pixels. A relationship was found between image analysis parameters and PHA concentration. In conclusion, it may be inferred that the present image analysis procedure is suitable to quantify PHA granules in SBB staining images and a promising alternative to standard analysis.

Improving evaluation of the distribution and density of immunostained cells in breast cancer using computerized video image analysis

Coventry, B.; Weightman, M.; Skinner, J.; Bradley, J.
Fonte: Dove Medical Press Ltd Publicador: Dove Medical Press Ltd
Tipo: Artigo de Revista Científica
Publicado em //2011 EN
Relevância na Pesquisa
65.9%
Quantitation of cell density in tissues has proven problematic over the years. The manual microscopic methodology, where an investigator visually samples multiple areas within slides of tissue sections, has long remained the basic 'standard' for many studies and for routine histopathologic reporting. Nevertheless, novel techniques that may provide a more standardized approach to quantitation of cells in tissue sections have been made possible by computerized video image analysis methods over recent years. The present study describes a novel, computer-assisted video image analysis method of quantitating immunostained cells within tissue sections, providing continuous graphical data. This technique enables the measurement of both distribution and density of cells within tissue sections. Specifically, the study considered immunoperoxidase-stained tumor infiltrating lymphocytes within breast tumor specimens, using the number of immunostained pixels within tissue sections to determine cellular density and number. Comparison was made between standard manual graded quantitation methods and video image analysis, using the same tissue sections. The study demonstrates that video image techniques and computer analysis can provide continuous data on cell density and number in immunostained tissue sections...

On the Development of the Convective Boundary Layer in a Shear-Free Thermally Forced Stably Stratified Fluid Setting: a 2D and 3D Experimental Investigation Using Image Analysis Techniques Coupled with Temperature Measurements

DORE, VALENTINA
Fonte: La Sapienza Universidade de Roma Publicador: La Sapienza Universidade de Roma
Tipo: Tese de Doutorado
EN
Relevância na Pesquisa
65.93%
The motion of buoyancy driven plumes is, on all scales, the most common heat and momentum transfer mechanism in geophysical flows, well known as Free Convection. Similarly, density stratification due to heating inequalities is also an ordinary scenario in nature. Free Convection phenomenon coupled with a density stratified fluid setting leads to the so-called Penetrative Free Convection (PFC). When a fluid, in static equilibrium, is stably stratified a thermal forcing can produce an unstable configuration ensuing internal waves formation of increasing amplitude. If the perturbation is strong enough, it can definitely erode the initial stratification and cause the motion of turbulent buoyant updrafts, dome-shaped, compensated by denser downdrafts. The entrainment phenomenon occurring at the interface between the turbulent and non-turbulent region justifies the penetrative feature of convection and causes the non linear growth of the Convective Boundary Layer (CBL) of well mixed fluid against the adjacent stably stratified region. In addition to the wide engineering applications, the environmental impact mostly motivates PFC studies. The upper lakes and oceans, under calm conditions, usually exhibit a continuous, moderately stable density distribution. Turbulent convective flow can be generated both by the free-surface cooling and wind shear-stress...

Quantification of fracture properties and microstructural features of roasted Marcona almonds by image analysis

Varela, Paula; Aguilera, José Miguel; Fiszman, Susana
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 986934 bytes; application/pdf
ENG
Relevância na Pesquisa
65.88%
The final version of the present paper is available at: http://dx.doi.org/10.1016/j.lwt.2007.02.013.; A method to quantify fracture pattern and microstructural heat damage through image analysis was proposed. The microstructure of Marcona almonds with different degrees of roasting (200 °C; 0, 1.5, 3, 4.5, 6 min) was related with their compression and fracture behaviour. Mechanical tests were performed with a TAXT2 texture analyser. The fracture pattern was characterized by measuring the particle size distribution with image analysis after compression. Light microscopy (LM) and scanning electron microscopy (SEM) were used to observe the changes in the microstructure of the almonds during roasting. The use of image analysis to quantify micro- and macro-structural features proved to be a very useful tool for analysing the crispness/crunchiness behaviour of the samples. The disruption of the inner parenchyma in the samples roasted for longer times proved to be the principal cause of their increased brittleness. The heterogeneity caused by heat degradation contributed to the failure of the material under compression, changing it from a deformable hard solid (raw sample) to a brittle one with enhanced crispy/crunchy characteristics.; The authors are indebted to the Ministerio de Educación y Ciencia (Spain) for the grant awarded to the author Paula Varela. Funding from the Fondecyt proyect 1030913 is appreciated (Chile).; Peer reviewed

Using n-dimensional volumes for mathematical applications in spectral image analysis

Ziemann, Amanda
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
65.92%
The ability to detect an object or activity -- such as a military vehicle, construction area, campsite, or vehicle tracks -- is highly important to both military and civilian applications. Sensors that process multi and hyperspectral images provide a medium for performing such tasks. Hyperspectral imaging is a technique for collecting and processing imagery at a large number of visible and non-visible wavelengths. Different materials exhibit different trends in their spectra, which can be used to analyze the image. For an image collected at n different wavelengths, the spectrum of each pixel can be mathematically represented as an n-element vector. The algorithm established in this work, the Simplex Volume Estimation algorithm (SVE), focuses specifically on change detection and large area search. In hyperspectral image analysis, a set of pixels constitutes a data cloud, with each pixel corresponding to a vector endpoint in Euclidean space. The SVE algorithm takes a geometrical approach to image analysis based on the linear mixture model, which describes each pixel in an image collected at n spectral bands as a linear combination of n+1 pure-material component spectra (known as endmembers). Iterative endmember identification is used to construct a 'volume function...