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1.
Skin Res Technol ; 29(1): e13268, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36704880

RESUMO

BACKGROUND: There is no method that can guarantee effective, quick, and noninvasive removal of tattoo dyes. Laser methods are considered to be the method of choice. In this study, an attempt was made to determine the in vitro spectral characteristics of selected dyes used in permanent makeup and tattoos and to analyze the obtained parameters in terms of laser treatments optimization. MATERIALS AND METHODS: Hyperspectral analysis was performed to determine the spectral characteristics of the dye on the entire surface of the slide. Seven dyes used in permanent makeup and tattoos were analyzed in vitro. The maximum reflectance and the wavelength for a given dye were determined for the maximum reflectance in the studied wavelength range: 400-1000 nm. The optical properties of the dyes were determined based on visible light imaging using camera. RESULTS: The maximum radiation reflectance ranges from 634 to 732 nm for the tested dyes. Visually very similar colors may differ significantly in the wavelength for which the maximum absorption of the radiation occurs. White and yellow dyes are characterized by the highest reflectance value. The black dye is characterized by the lowest reflectance coefficient. Low reflectance of black dye results in more safe and effective removal treatments. CONCLUSION: The homogeneity of radiation absorption can be identified using methods of analysis and processing of images in visible light. Optimization of the wavelength of which the maximum absorption/reflectance of radiation occurs may allow us to increase the effectiveness of laser treatments for removing permanent makeup and tattoos.


Assuntos
Terapia a Laser , Tatuagem , Humanos , Terapia a Laser/métodos , Imageamento Hiperespectral , Corantes , Luz
2.
Skin Res Technol ; 28(3): 427-432, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35253948

RESUMO

BACKGROUND: About 90% of women worldwide use nail care products, including manicure ones. A manicure procedure results in nail damage, therefore it is necessary to search for new, objective methods of assessing the impact of the procedures and products applied within the nail plate. In this study, an attempt was made to quantify the impact of manicure procedures on the nail plate condition. MATERIALS AND METHODS: Twenty thumb nail plates were examined. Before the manicure procedures, alginate casts were prepared for each of the subjects. The analysis of the three-dimensional (3D) nail surface structure included the assessment of the nail sections and the assessment of differences in the nail structure after superposition of 3D images of the nail plates before and after the manicure procedures. RESULTS: The obtained results show that the nail plate structure changed to a similar extent in each measured section after the manicure procedure. A change in the height of the nails is not a desirable phenomenon as it suggests damage to the nail caused by the substances included in the preparations applied to the nails, acetone, or filing the nail plate. This proves the great influence of the technique of removing artificial nails on the structure of the natural plate. CONCLUSION: The use of a 3D scanner allows for precise, biometric, quantitative, and repeatable measurements of changes in the nail structure after a manicure procedure. The use of the hybrid and gel manicure procedure causes significant damage to the nail plate, especially in its distal portion.


Assuntos
Doenças da Unha , Unhas , Feminino , Humanos , Unhas/diagnóstico por imagem
3.
J Therm Biol ; 96: 102823, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33627263

RESUMO

Infrared thermal imaging is currently used in almost every field of medicine. This paper presents the novel use of thermography in ophthalmology - using a thermal camera to assess correct intraocular pressure measurement depending on the position of the patient's head during non-contact tonometry. For the analysed group of 10 healthy subjects, thermographic images of the face were recorded before and after intraocular pressure testing. Pressure was tested with a non-contact tonometer with a Scheimpflug camera. For the acquired 20: 2D images (thermograms), an analysis of the characteristic areas of the face determined temperature changes of the patient's face in contact with the tonometer frame. Analysis and processing of the acquired thermograms was carried out in MATLAB® with the Image Processing Toolbox. The results clearly showed a decrease in the patient's face temperature where the face was in contact with tonometer supports. Temperature changes in the patient's face provide valuable information about the correct position of their head in the device, which directly translates into measurement quality. Therefore, the analysis of changes in the patient's face temperature both before and after the examination can be a tool for assessing correct patient positioning in the tonometer supports.


Assuntos
Face/fisiologia , Termografia , Tonometria Ocular , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Pressão Intraocular , Masculino , Pessoa de Meia-Idade , Posicionamento do Paciente , Termografia/instrumentação , Termografia/métodos , Tonometria Ocular/instrumentação , Tonometria Ocular/métodos
4.
Biomed Eng Online ; 18(1): 17, 2019 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-30760270

RESUMO

BACKGROUND: Non-contact tonometers based on the method using air puff and Scheimpflug's fast camera are one of the latest devices allowing the measurement of intraocular pressure and additional biomechanical parameters of the cornea. Biomechanical features significantly affect changes in intraocular pressure values, as well as their changes, may indicate the possibility of corneal ectasia. This work presents the latest and already known biomechanical parameters available in the new offered software. The authors focused on their practical application and the diagnostic credibility indicated in the literature. DISCUSSION: An overview of available literature indicates the importance of new dynamic corneal parameters. The latest parameters developed on the basis of biomechanics analysis of corneal deformation process, available in non-contact tonometers using Scheimpflug's fast camera, are used in the evaluation of laser refractive surgery procedures, e.g. LASIK procedure. In addition, the assessment of changes in biomechanically corrected intraocular pressure confirms its independence from changes in the corneal biomechanics which may allow an intraocular pressure real assessment. The newly developed Corvis Biomechanical Index combined with the corneal tomography and topography assessment is an important aid in the classification of patients with keratoconus. CONCLUSION: New parameters characterising corneal deformation, including Corvis Biomechanical Index and biomechanical compensated intraocular pressure, significantly extend the diagnostic capabilities of this device and may be helpful in assessing corneal diseases of the eye. Nevertheless, further research is needed to confirm their diagnostic pertinence.


Assuntos
Córnea/fisiologia , Tonometria Ocular/métodos , Ar , Fenômenos Biomecânicos , Córnea/cirurgia , Humanos
5.
Biomed Eng Online ; 18(1): 115, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31796067

RESUMO

BACKGROUND: The Corvis® ST tonometer is an innovative device which, by combining a classic non-contact tonometer with an ultra-fast Scheimpflug camera, provides a number of parameters allowing for the assessment of corneal biomechanics. The acquired biomechanical parameters improve medical diagnosis of selected eye diseases. One of the key elements in biomechanical measurements is the correct corneal contour detection, which is the basis for further calculations. The presented study deals with the problem of outer corneal edge detection based on a series of images from the afore-mentioned device. Corneal contour detection is the first and extremely important stage in the acquisition and analysis of corneal dynamic parameters. RESULT: A total of 15,400 images from the Corvis® ST tonometer acquired from 110 patients undergoing routine ophthalmologic examinations were analysed. A method of outer corneal edge detection on the basis of a series of images from the Corvis® ST was proposed. The method was compared with known and commonly used edge detectors: Sobel, Roberts, and Canny operators, as well as others, known from the literature. The analysis was carried out in MATLAB® version 9.0.0.341360 (R2016a) with the Image Processing Toolbox (version 9.4) and the Neural Network Toolbox (version 9.0). The method presented in this paper provided the smallest values of the mean error (0.16%), stability (standard deviation 0.19%) and resistance to noise, characteristic for Corvis® ST tonometry tests, compared to the methods known from the literature. The errors were 5.78 ± 9.19%, 3.43 ± 6.21%, and 1.26 ± 3.11% for the Roberts, Sobel, and Canny methods, respectively. CONCLUSIONS: The proposed new method for detecting the outer corneal contour increases the accuracy of intraocular pressure measurements. It can be used to analyse dynamic parameters of the cornea.


Assuntos
Córnea/diagnóstico por imagem , Tonometria Ocular/instrumentação , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Adulto Jovem
6.
Biomed Eng Online ; 17(1): 17, 2018 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-29391026

RESUMO

This article is a review of the book "Master machine learning algorithms, discover how they work and implement them from scratch" (ISBN: not available, 37 USD, 163 pages) edited by Jason Brownlee published by the Author, edition, v1.10 http://MachineLearningMastery.com . An accompanying commentary discusses some of the issues that are involved with use of machine learning and data mining techniques to develop predictive models for diagnosis or prognosis of disease, and to call attention to additional requirements for developing diagnostic and prognostic algorithms that are generally useful in medicine. Appendix provides examples that illustrate potential problems with machine learning that are not addressed in the reviewed book.

7.
Biomed Eng Online ; 17(1): 108, 2018 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-30103748

RESUMO

BACKGROUND: To improve accuracy of IOLMaster (Carl Zeiss, Jena, Germany) in corneal power measurement after myopic excimer corneal refractive surgery (MECRS) using multivariate polynomial analysis (MPA). METHODS: One eye of each of 403 patients (mean age 31.53 ± 8.47 years) was subjected to MECRS for a myopic defect, measured as spherical equivalent, ranging from - 9.50 to - 1 D (mean - 4.55 ± 2.20 D). Each patient underwent a complete eye examination and IOLMaster scan before surgery and at 1, 3 and 6 months follow up. Axial length (AL), flatter keratometry value (K1), steeper keratometry value (K2), mean keratometry value (KM) and anterior chamber depth measured from the corneal endothelium to the anterior surface of the lens (ACD) were used in a MPA to devise a method to improve accuracy of KM measurements. RESULTS: Using AL, K1, K2 and ACD measured after surgery in polynomial degree 2 analysis, mean error of corneal power evaluation after MECRS was + 0.16 ± 0.19 D. CONCLUSIONS: MPA was found to be an effective tool in devising a method to improve precision in corneal power evaluation in eyes previously subjected to MECRS, according to our results.


Assuntos
Córnea/cirurgia , Interferometria/métodos , Procedimentos Cirúrgicos Refrativos , Estatística como Assunto , Adolescente , Adulto , Córnea/fisiologia , Feminino , Humanos , Luz , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Adulto Jovem
8.
Biomed Eng Online ; 16(1): 82, 2017 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-28646862

RESUMO

BACKGROUND: Meibomian gland dysfunction (MGD) is one of the most common diseases observed in clinics and is the leading cause of evaporative dry eye. Today, diagnostics of MGD is not fully automatic yet and is based on a qualitative assessment made by an ophthalmologist. Therefore, an automatic analysis method was developed to assess MGD quantiatively. MATERIALS: The analysis made use of 228 images of 57 patients recorded by OCULUS Keratograph® 5 M with a resolution of 1024 × 1360 pixels concern 30 eyes of healthy individuals (14 women and 16 men) and 27 eyes of sick patients (10 women and 17 men). The diagnosis of dry eye was made according to the consensus of DED in China (2013). METHODS: The presented method of analysis is a new, developed method enabling an automatic, reproducible and quantitative assessment of Meibomian glands. The analysis relates to employing the methods of analysis and image processing. The analysis was conducted in the Matlab environment Version 7.11.0.584, R2010b, Java VM Version: Java 1.6.0_17-b04 with Sun Microsystems Inc. with toolboxes: Statistical, Signal Processing and Image Processing. RESULTS: The presented, new method of analysis of Meibomian glands is fully automatic, does not require operator's intervention, allows obtaining reproducible results and enables a quantitative assessment of Meibomian glands. Compared to the other known methods, particularly with the method described in literature it allows obtaining better sensitivity (98%) and specificity (100%) results by 2%.


Assuntos
Processamento de Imagem Assistida por Computador , Glândulas Tarsais/diagnóstico por imagem , Automação , Estudos de Casos e Controles , Doenças Palpebrais/diagnóstico por imagem , Doenças Palpebrais/fisiopatologia , Feminino , Humanos , Masculino , Glândulas Tarsais/fisiopatologia , Processamento de Sinais Assistido por Computador
9.
Molecules ; 22(8)2017 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-28758947

RESUMO

The aim of the present study is to quantitatively assess the expression of selected regulatory molecules, such as leptin, leptin receptor, and adiponectin in the blood of obese patients with type 2 diabetes both before treatment and after six months of pharmacological therapy with the long-lasting insulin analogue, insulin detemir. A significant decrease in the analysed regulatory molecules, i.e., leptin receptor and adiponectin, was found in blood plasma of the patients with untreated type 2 diabetes. These changes were accompanied by an increase in plasma leptin concentrations. Insulin treatment resulted in the normalization of plasma leptin receptor and adiponectin concentrations. The circulating leptin level did not change following anti-diabetic therapy with insulin detemir. Gender was a significant factor modifying the circulating level of all the analysed regulatory active compounds. Bioinformatic analysis was performed using Matlab with the Signal Processing Toolbox. The conducted discriminant analysis revealed that the leptin receptor, Δw(19), and adiponectin, Δw(21), were the parameters undergoing the most significant quantitative changes during the six-month therapy with insulin detemir. The conducted examinations indicated the contribution of adipocytokines-the biologically-active mediators of systemic metabolism, such as leptin and adiponectin in the pathomechanism of disorders being the basis for obesity which leads to development of insulin resistance, which, in turn, results in the occurrence of type 2 diabetes.


Assuntos
Adiponectina/sangue , Diabetes Mellitus Tipo 2 , Insulina Detemir/administração & dosagem , Leptina/sangue , Obesidade , Receptores para Leptina/sangue , Adulto , Idoso , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/tratamento farmacológico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/sangue , Obesidade/tratamento farmacológico , Fatores Sexuais
10.
Biomed Eng Online ; 15(1): 111, 2016 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-27716321

RESUMO

BACKGROUND: The paper presents an automatic method for analysis and processing of images from a camera operating in visible light. This analysis applies to images containing the human facial area (body) and enables to measure the blood pulse rate. Special attention was paid to the limitations of this measurement method taking into account the possibility of using consumer cameras in real conditions (different types of lighting, different camera resolution, camera movement). METHODS: The proposed new method of image analysis and processing was associated with three stages: (1) image pre-processing-allowing for the image filtration and stabilization (object location tracking); (2) main image processing-allowing for segmentation of human skin areas, acquisition of brightness changes; (3) signal analysis-filtration, FFT (Fast Fourier Transformation) analysis, pulse calculation. RESULTS AND CONCLUSIONS: The presented algorithm and method for measuring the pulse rate has the following advantages: (1) it allows for non-contact and non-invasive measurement; (2) it can be carried out using almost any camera, including webcams; (3) it enables to track the object on the stage, which allows for the measurement of the heart rate when the patient is moving; (4) for a minimum of 40,000 pixels, it provides a measurement error of less than ±2 beats per minute for p < 0.01 and sunlight, or a slightly larger error (±3 beats per minute) for artificial lighting; (5) analysis of a single image takes about 40 ms in Matlab Version 7.11.0.584 (R2010b) with Image Processing Toolbox Version 7.1 (R2010b).


Assuntos
Testes de Função Cardíaca/métodos , Frequência Cardíaca , Luz , Face , Humanos , Processamento de Imagem Assistida por Computador
11.
Biomed Eng Online ; 15(1): 97, 2016 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-27535027

RESUMO

BACKGROUND: Segmentation of hyperspectral medical images is one of many image segmentation methods which require profiling. This profiling involves either the adjustment of existing, known image segmentation methods or a proposal of new dedicated methods of hyperspectral image segmentation. Taking into consideration the size of analysed data, the time of analysis is of major importance. Therefore, the authors proposed three new dedicated methods of hyperspectral image segmentation with special reference to the time of analysis. METHODS: The segmentation methods presented in this paper were tested and profiled to the images acquired from different hyperspectral cameras including SOC710 Hyperspectral Imaging System, Specim sCMOS-50-V10E. Correct functioning of the method was tested for over 10,000 2D images constituting the sequence of over 700 registrations of the areas of the left and right hand and the forearm. RESULTS: As a result, three new methods of hyperspectral image segmentation have been proposed: fast analysis of emissivity curves (SKE), 3D segmentation (S3D) and hierarchical segmentation (SH). They have the following features: are fully automatic; allow for implementation of fast segmentation methods; are profiled to hyperspectral image segmentation; use emissivity curves in the model form, can be applied in any type of objects not necessarily biological ones, are faster (SKE-2.3 ms, S3D-1949 ms, SH-844 ms for the computer with Intel(®) Core i7 4960X CPU 3.6 GHz) and more accurate (SKE-accuracy 79 %, S3D-90 %, SH-92 %) in comparison with typical methods known from the literature. CONCLUSIONS: Profiling and/or proposing new methods of hyperspectral image segmentation is an indispensable element of developing software. This ensures speed, repeatability and low sensitivity of the algorithm to changing parameters.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Pele , Adulto , Algoritmos , Feminino , Humanos , Imageamento Tridimensional , Masculino , Pessoa de Meia-Idade , Pele/citologia , Fatores de Tempo , Adulto Jovem
12.
Biomed Eng Online ; 15(1): 88, 2016 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-27456974

RESUMO

BACKGROUND: Currently available perimeters have limited capabilities of performing measurements of the visual field in children. In addition, they do not allow for fully automatic measurement even in adults. The patient in each case (in any type of perimeter) has at his disposal a button which he uses to indicate that he has seen a light stimulus. Such restrictions have been offset in the presented new perimeter ZERK 1. METHODS: The paper describes a new type of automated, computerized perimeter designed to test the visual field in children and adults. The new perimeter and proprietary software enable to carry out tests automatically (without the need to press any button). The presented full version of the perimeter has been tested on a head phantom. The next steps will involve clinical trials and a comparison with measurements obtained using other types of perimeters. RESULTS: The perimeter ZERK 1 enables automatic measurement of the visual field in two axes (with a span of 870 mm and a depth of 525 mm) with an accuracy of not less than 1(o) (95 LEDs on each arm) at a typical position of the patient's head. The measurement can be carried out in two modes: default/typical (lasting about 1 min), and accurate (lasting about 10 min). Compared with available and known types of perimeters, it has an open canopy, proprietary software and cameras tracking the eye movement, automatic control of fixation points, light stimuli with automatically preset light stimulus intensity in the following ranges: 550-700 mcd (red 620-630 nm), 1100-1400 mcd (green 515-530 nm), 200-400 mcd (blue 465-475 nm). CONCLUSIONS: The paper presents a new approach to the construction of perimeters based on automatic tracking of the eye movements in response to stimuli. The unique construction of the perimeter and the software allow for its mobile use in the examination of children and bedridden patients.


Assuntos
Testes Visuais/métodos , Campos Visuais , Adulto , Automação , Criança , Humanos , Software , Testes Visuais/instrumentação
13.
Biomed Eng Online ; 15(1): 121, 2016 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-27846894

RESUMO

BACKGROUND: Efficacy and high availability of surgery techniques for refractive defect correction increase the number of patients who undergo to this type of surgery. Regardless of that, with increasing age, more and more patients must undergo cataract surgery. Accurate evaluation of corneal power is an extremely important element affecting the precision of intraocular lens (IOL) power calculation and errors in this procedure could affect quality of life of patients and satisfaction with the service provided. The available device able to measure corneal power have been tested to be not reliable after myopic refractive surgery. METHODS: Artificial neural networks with error backpropagation and one hidden layer were proposed for corneal power prediction. The article analysed the features acquired from the Pentacam HR tomograph, which was necessary to measure the corneal power. Additionally, several billion iterations of artificial neural networks were conducted for several hundred simulations of different network configurations and different features derived from the Pentacam HR. The analysis was performed on a PC with Intel® Xeon® X5680 3.33 GHz CPU in Matlab® Version 7.11.0.584 (R2010b) with Signal Processing Toolbox Version 7.1 (R2010b), Neural Network Toolbox 7.0 (R2010b) and Statistics Toolbox (R2010b). RESULTS AND CONCLUSIONS: A total corneal power prediction error was obtained for 172 patients (113 patients forming the training set and 59 patients in the test set) with an average age of 32 ± 9.4 years, including 67% of men. The error was at an average level of 0.16 ± 0.14 diopters and its maximum value did not exceed 0.75 dioptres. The Pentacam parameters (measurement results) providing the above result are tangential anterial/posterior. The corneal net power and equivalent k-reading power. The analysis time for a single patient (a single eye) did not exceed 0.1 s, whereas the time of network training was about 3 s for 1000 iterations (the number of neurons in the hidden layer was 400).


Assuntos
Córnea/cirurgia , Topografia da Córnea , Miopia/cirurgia , Redes Neurais de Computação , Procedimentos Cirúrgicos Refrativos , Adulto , Algoritmos , Córnea/patologia , Córnea/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Miopia/patologia , Miopia/fisiopatologia , Qualidade de Vida , Resultado do Tratamento , Adulto Jovem
15.
Biomed Eng Online ; 14: 111, 2015 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-26626725

RESUMO

The paper presents an overview of endoscopic capsules with particular emphasis on technical aspects. It indicates common problems in capsule endoscopy such as: (1) limited wireless communication (2) the use of capsule endoscopy in the case of partial patency of the gastrointestinal tract, (3) limited imaging area, (4) external capsule control limitations. It also presents the prospects of capsule endoscopy, the most recent technical solutions for biopsy and the mobility of the capsule in the gastrointestinal tract. The paper shows the possibilities of increasing clinical usefulness of capsule endoscopy resulting from technological limitations. Attention has also been paid to the current role of capsule endoscopy in screening tests and the limitations of its effectiveness. The paper includes the author's recommendations concerning the direction of further research and the possibility of enhancing the scope of capsule endoscopy.


Assuntos
Endoscopia por Cápsula/métodos , Biópsia , Endoscopia por Cápsula/instrumentação , Humanos , Movimento (Física) , Fatores de Tempo , Tecnologia sem Fio
16.
Biomed Eng Online ; 14: 31, 2015 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-25889898

RESUMO

BACKGROUND: The software supplied with the Corvis tonometer (which is designed to measure intraocular pressure with the use of the air-puff method) is limited to providing basic numerical data. These data relate to the values of the measured intraocular pressure and, for example, applanation amplitudes. However, on the basis of a sequence of images obtained from the Corvis tonometer, it is possible to obtain much more information which is not available in its original software. This will be presented in this paper. MATERIAL AND METHOD: The proposed software has been tested on 1400 images from the Corvis tonometer. The number of analysed 2D images (with a resolution of 200 × 576 pixels) in a sequence is arbitrary. However, in typical cases there are 140 images. The proposed software has been written in Matlab (Version 7.11.0.584, R2010b). The methods of image analysis and processing and in particular edge detection and the fast Fourier transform have been applied. RESULTS AND DISCUSSION: The software allows for fully automatic (1) acquisition of 12 new parameters previously unavailable in the original software of the Corvis tonometer. It also enables off-line (2) manual and (3) automatic browsing of images in a sequence; 3D graph visualization of: (4) the corneal deformation and (5) eyeball response; 6) change of the colour palette; (7) filtration and (8) visualization of selected measured values on individual 2D images. In addition, the proposed software enables (9) to save the obtained results for further analysis and processing. CONCLUSIONS: The dedicated software described in this paper enables to obtain additional new features of corneal deformations during intraocular pressure measurement. The software can be applied in the diagnosis of corneal deformation vibrations, glaucoma diagnosis, evaluation of measurement repeatability and others. The software has no licensing restrictions and can be used both commercially and non-commercially without any limitations.


Assuntos
Córnea/ultraestrutura , Glaucoma/diagnóstico , Processamento de Imagem Assistida por Computador/métodos , Pressão Intraocular , Software , Tonometria Ocular , Análise de Fourier , Humanos , Publicação de Acesso Aberto , Tonometria Ocular/instrumentação , Tonometria Ocular/estatística & dados numéricos , Interface Usuário-Computador , Vibração , Substâncias Viscoelásticas
17.
J Opt Soc Am A Opt Image Sci Vis ; 32(8): 1446-53, 2015 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-26367287

RESUMO

Pulsation in the blood vessels of the eye has a big impact on the dynamics of the entire eyeball and its individual elements. Blood pulsation in the retina can be recorded by the pupil, whose size is also subject to dynamic changes. The study involved synchronous measurements of pupil size using a high-speed camera, and blood pulsation using a pulse oximeter placed on the ear lobe. In addition, there were no metrologically significant differences in the phase shift between the average brightness of the individual pupil quadrants. Blood pulsation in other ocular tissues can affect the dynamics of the optical properties of the eye. As demonstrated in this paper, it affects the pupil behavior and its parameters to a considerable extent.


Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Raios Infravermelhos , Fotometria/métodos , Fluxo Pulsátil/fisiologia , Pulso Arterial/métodos , Pupila/fisiologia , Algoritmos , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
18.
Biomed Eng Online ; 13: 150, 2014 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-25406740

RESUMO

INTRODUCTION: The method for measuring intraocular pressure using the Corvis tonometer provides a sequence of images of corneal deformation. Deformations of the cornea are recorded using the ultra-high-speed Scheimpflug camera. This paper presents a new and reproducible method of analysis of corneal deformation images that allows for automatic measurements of new features, namely new three parameters unavailable in the original software. MATERIAL AND METHOD: The images subjected to processing had a resolution of 200 × 576 × 140 pixels. They were acquired from the Corvis tonometer and simulation. In total 14,000 2D images were analysed. The image analysis method proposed by the author automatically detects the edge of the cornea and sclera fragments. For this purpose, new methods of image analysis and processing proposed by the author as well as those well-known, such as Canny filter, binarization, median filtering etc., have been used. The presented algorithms were implemented in Matlab (version 7.11.0.584-R2010b) with Image Processing toolbox (version 7.1-R2010b) using both known algorithms for image analysis and processing and those proposed by the author. RESULTS: Owing to the proposed algorithm it is possible to determine three parameters: (1) the degree of the corneal reaction relative to the static position; (2) the corneal length changes; (3) the ratio of amplitude changes to the corneal deformation length. The corneal reaction is smaller by about 30.40% compared to its static position. The change in the corneal length during deformation is very small, approximately 1% of its original length. Parameter (3) enables to determine the applanation points with a correlation of 92% compared to the conventional method for calculating corneal flattening areas. The proposed algorithm provides reproducible results fully automatically within a few seconds/per patient using Core i7 processor. CONCLUSIONS: Using the proposed algorithm, it is possible to measure new, additional parameters of corneal deformation, which are not available in the original software. The presented analysis method provides three new parameters of the corneal reaction. Detailed clinical studies based on this method will be presented in subsequent papers.


Assuntos
Córnea/anormalidades , Córnea/patologia , Processamento de Imagem Assistida por Computador/métodos , Pressão Intraocular , Tonometria Ocular , Algoritmos , Automação , Fenômenos Biomecânicos , Simulação por Computador , Humanos , Reprodutibilidade dos Testes , Software
19.
Biomed Eng Online ; 13: 93, 2014 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-24997012

RESUMO

INTRODUCTION: Dedicated, automatic algorithms for image analysis and processing are becoming more and more common in medical diagnosis. When creating dedicated algorithms, many factors must be taken into consideration. They are associated with selecting the appropriate algorithm parameters and taking into account the impact of data acquisition on the results obtained. An important feature of algorithms is the possibility of their use in other medical units by other operators. This problem, namely operator's (acquisition) impact on the results obtained from image analysis and processing, has been shown on a few examples. MATERIAL AND METHOD: The analysed images were obtained from a variety of medical devices such as thermal imaging, tomography devices and those working in visible light. The objects of imaging were cellular elements, the anterior segment and fundus of the eye, postural defects and others. In total, almost 200'000 images coming from 8 different medical units were analysed. All image analysis algorithms were implemented in C and Matlab. RESULTS: For various algorithms and methods of medical imaging, the impact of image acquisition on the results obtained is different. There are different levels of algorithm sensitivity to changes in the parameters, for example: (1) for microscope settings and the brightness assessment of cellular elements there is a difference of 8%; (2) for the thyroid ultrasound images there is a difference in marking the thyroid lobe area which results in a brightness assessment difference of 2%. The method of image acquisition in image analysis and processing also affects: (3) the accuracy of determining the temperature in the characteristic areas on the patient's back for the thermal method - error of 31%; (4) the accuracy of finding characteristic points in photogrammetric images when evaluating postural defects - error of 11%; (5) the accuracy of performing ablative and non-ablative treatments in cosmetology - error of 18% for the nose, 10% for the cheeks, and 7% for the forehead. Similarly, when: (7) measuring the anterior eye chamber - there is an error of 20%; (8) measuring the tooth enamel thickness - error of 15%; (9) evaluating the mechanical properties of the cornea during pressure measurement - error of 47%. CONCLUSIONS: The paper presents vital, selected issues occurring when assessing the accuracy of designed automatic algorithms for image analysis and processing in bioengineering. The impact of acquisition of images on the problems arising in their analysis has been shown on selected examples. It has also been indicated to which elements of image analysis and processing special attention should be paid in their design.


Assuntos
Diagnóstico por Imagem/métodos , Processamento de Imagem Assistida por Computador/métodos , Algoritmos , Olho/citologia , Humanos , Posicionamento do Paciente , Postura , Dente/citologia
20.
Biomed Eng Online ; 13: 16, 2014 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-24528923

RESUMO

INTRODUCTION: In many practical aspects of ophthalmology, it is necessary to assess the severity degree of glaucoma in cases where, for various reasons, it is impossible to perform a visual field test - static perimetry. These are cases in which the visual field test result is not reliable, e.g. advanced AMD (Age-related Macular Degeneration). In these cases, there is a need to determine the severity of glaucoma, mainly on the basis of optic nerve head (ONH) and retinal nerve fibre layer (RNFL) structure. OCT is one of the diagnostic methods capable of analysing changes in both, ONH and RNFL in glaucoma. MATERIAL AND METHOD: OCT images of the eye fundus of 55 patients (110 eyes) were obtained from the SOCT Copernicus (Optopol Tech. SA, Zawiercie, Poland). The authors proposed a new method for automatic determination of the RNFL (retinal nerve fibre layer) and other parameters using: mathematical morphology and profiled segmentation based on morphometric information of the eye fundus. A quantitative ratio of the quality of the optic disk and RNFL - BGA (biomorphological glaucoma advancement) was also proposed. The obtained results were compared with the results obtained from a static perimeter. RESULTS: Correlations between the known parameters of the optic disk as well as those suggested by the authors and the results obtained from static perimetry were calculated. The result of correlation with the static perimetry was 0.78 for the existing methods of image analysis and 0.86 for the proposed method. Practical usefulness of the proposed ratio BGA and the impact of the three most important features on the result were assessed. The following results of correlation for the three proposed classes were obtained: cup/disk diameter 0.84, disk diameter 0.97 and the RNFL 1.0. Thus, analysis of the supposed visual field result in the case of glaucoma is possible based only on OCT images of the eye fundus. CONCLUSIONS: The calculations and analyses performed with the proposed algorithm and BGA ratio confirm that it is possible to calculate supposed mean defect (MD) of the visual field test based on OCT images of the eye fundus.


Assuntos
Glaucoma/fisiopatologia , Processamento de Imagem Assistida por Computador/métodos , Tomografia de Coerência Óptica/métodos , Campos Visuais , Automação , Glaucoma/diagnóstico , Humanos
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