Wyniki wyszukiwania - Biblioteka Nauki

1

Optical coherence tomography image for automatic classification of diabetic macular edema

100%

Wang P. , Li J.-L. , Ding H.

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2020

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tom Vol. 50, nr 4

567--577

EN

Diabetic macular edema (DME) is the dominant reason of diabetic visual loss, so early detection and treatment of DME is of great significance for the treatment of diabetes. Based on transfer learning, an automatic classification method is proposed to distinguish DME images from normal images in optical coherence tomography (OCT) retinal fundus images. Features of the DME are automatically identified and extracted by the pre-trained convolutional neural network (CNN), which only involves fine-tuning the VGGNet-16 network without any user intervention. An accuracy of 97.9% and a sensitivity of 98.0% are acquired with the OCT images in the Duke data set from experimental results. The proposed method, a core part of an automated diagnosis system of the DME, revealed the ability of fine-tuning models to train non-medical images, allowing them can be classified with limited training data. Moreover, it can be developed to assist early diagnosis of the disease, effectively delaying (or avoiding) the progression of the disease, consequently.

2

Intraoperative imaging based on common-path time-domain reflectometry for brain tumor surgery

100%

Han J.-H. , Cha J.

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2020

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tom Vol. 50, nr 2

223--227

EN

Minimally invasive intraoperative imaging plays a crucial role in delicate microsurgeries for precise operation monitoring in which fiber optic imaging can be considered as an endoscopy and surgical proximity guidance tool due to its compactness. This paper presents a near-infrared time-domain reflectometric common-path optical coherence tomography imaging technique using a bare-fiber probe mounted directly on a scanning galvanometer. The common-path setup allows the use of a freely adjustable optical path length and a disposable fiber probe, as well as eliminating the need for an additional dedicated reference optical path. Experimental results demonstrate clear discrimination between the brain tumor tissue and the normal tissue for mouse brains with the images acquired in real-time over a wide area. The proposed method enables real-time and in situ visualization of tumor resection for intraoperative imaging, and this study demonstrates the feasibility of its application to microsurgical interventions.

3

The Detection of Internal Fingerprint Image Using Optical Coherence Tomography

100%

Sekulska-Nalewajko J. , Gocławski J. , Sankowski D.

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2017

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tom Vol. 22, no. 4

59--72

EN

Recently, optical coherence tomography (OCT) has been tested as a contactless technique helpful for damaged or spoofed fingerprint recovery. Three dimensional OCT images cover the range from the skin surface to papillary region in upper dermis. The proposed method extracts from B-scans high intensity ridges in both air-epidermis and dermis-epidermis interfaces. The extraction is based on the localisation of two OCT signal peaks corresponding to these edges. The borders are spline smoothed in two orthogonal planes of the image space. The result images are presented and compared with camera views.

4

Optyczna tomografia koherentna w badaniach technicznych obiektów rozpraszających

100%

Strąkowski M. , Pluciński J.

Zeszyty Naukowe Wydziału ETI Politechniki Gdańskiej. Technologie Informacyjne

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2010

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tom T. 19

413-418

PL

Optyczna tomografia koherentna (OCT) jest nieinwazyjną i bezkontaktową metodą badania wewnętrznej struktury materiałów i obiektów rozpraszających promieniowanie optyczne. Technika ta jest jedną z bardziej zaawansowanych metod pomiarowych należących do dziedziny NDT (ang. non-destructive testing) i NDE (ang. non-destructive evaluation). Umożliwia ona lokalizowanie oraz badanie defektów występujących wewnątrz badanego obiektu. W artykule omówiono właściwości metody, zakres i możliwości metrologiczne oraz przykładowe aplikacje. Przedstawiono wyniki pomiarów uzyskanych dla materiałów o zróżnicowanych właściwościach optycznych. Na podstawie przeprowadzonych eksperymentów wykazano przydatność OCT do badania jakości wytworzonych elementów oraz monitorowania zmian związanych z degradacją struktury testowanego obiektu.

EN

Optical coherence tomography (OCT) is an optical method, witch enables non-contact and non-destructive examination of inner structure of scattering materials. OCT is a one of the most advanced methods in NDT (non-destructive testing) and NDE (non-destructive evaluation) branch. With the aid of OCT the surface and subsurface defects can be investigated. In this paper the OCT features and measurements abilities have been presented, as well as applications examples. Moreover, the measurement results obtained for scattering materials have been shown. Based on those results the usefulness of the OCT and OCT limits have been discussed.

5

Readout System and Data Processing for OCT Pachymetry

100%

Dziewiecki M. , Domański G. , Frey W. , Konarzewski B. , Kurjata R. , Marzec J. , Smolnik A. , Zaremba K. , Ziembicki M.

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tom Vol. 56, No. 3

223-230

EN

A complete system for measurement control, signal acquisition and data processing for an OCT pachymeter is described. Moreover, dedicated data processing algorithm used for noise reduction is presented. A simple OCT scanner was built and some measurements were performed to examine the capabilities of the system.

6

Non-destructive inspection of anti-corrosion protective coatings using optical coherent tomography

100%

Antoniuk P. , Strąkowski M. R. , Pluciński J. , Kosmowski B. B.

Metrology and Measurement Systems

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2012

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tom Vol. 19, nr 2

365-372

EN

Optical Coherence Tomography (OCT) is one of the most rapidly advancing techniques. This method is capable of non-contact and non-destructive investigation of the inner structure of a broad range of materials. Compared with other methods which belong to the NDE/NDT group (Non-Destructive Evaluation/Non-Destructive Testing methods), OCT is capable of a broad range of scattering material structure visualization. Such a non-invasive and versatile method is very demanded by the industry. The authors applied the OCT method to examine the corrosion process in metal samples coated by polymer films. The main aim of the research was the evaluation of the anti-corrosion protective coatings using the OCT method. The tested samples were exposed to a harsh environment. The OCT measurements have been taken at different stages of the samples degradation. The research and tests results have been presented, as well as a brief discussion has been carried out.

7

Measurement of retina vessels by segmentation of images reconstructed from optical coherence tomography data

100%

Marciniak T. , Stankiewicz A. , Dąbrowski A. , Stopa M. , Rakowicz P. , Marciniak E.

Metrology and Measurement Systems

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2019

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tom Vol. 26, nr 3

449--461

EN

In this paper methods and their examination results for automatic segmentation and parameterization of vessels based on spectral domain optical coherence tomography (SD-OCT) of the retina are presented. We present three strategies for morphologic image processing of a fundus image reconstructed from OCT scans. A specificity of initial image processing for fundus reconstruction is analysed. Then, the parameterization step is performed based on the vessels segmented with the proposed algorithm. The influence of various methods on the vessel segmentation and fully automatic vessel measurement is analysed. Experiments were carried out with a set of 3D OCT scans obtained from 24 eyes (12 healthy volunteers) with the use of an Avanti RTvue OCT device. The results of automatic vessel segmentation were numerically compared with those prepared manually by the medical doctor experts.

8

The role of epithelial thickness mapping in corneal refractive surgery

88%

Wlaź A. , Czarnota-Nowakowska B. , Wierzbowska J.

OphthaTherapy

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2021

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tom 8

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nr 3

196-201

EN

Refractive surgery has stimulated significant progress in anterior segment imaging. Knowledge of epithelial thickness profile considerably increases the efficacy and safety of refractive procedures. This review aims to present new technologies evaluating corneal epithelial thickness and the most important clinical applications in the field of corneal refractive surgery.

9

Innovation in retinal diseases – ultra-widefield imaging

88%

Dolar-Szczasny J. , Święch-Zubilewicz A. , Mackiewicz J.

Polish Journal of Public Health

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2015

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tom 125

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nr 1

14-16

EN

The understanding of retinal disease has evolved rapidly with a growing number of clinical evidence supplied by ultrawidefield retinal imaging. Optos 200Tx ultra-widefield retinal imaging system uses a scanning laser ophthalmoscope, as well as an ellipsoid mirror. This creates a possibility of making a virtual focal point inside the eye and, in turn, enables the system to simultaneously make a single capture of the central retina and periphery. This system offers multimodal ultra-widefield imaging, including color photographs, fundus autofluorescence images, red-free images and fluorescein angiography (FA), allowing visualization of the retinal circulation. For color photographs, green and red lasers are used simultaneously to allow visualization of retinal substructures from the sensory retina and retinal pigment epithelium to the choroid. In our clinic ultra-widefield fluorescein angiography has became an elegant diagnostic imaging modality that has improved our ability to diagnose and plan treatment strategies. In the future widefield imaging will probably be coupled with OCT (optical coherence tomography) option to better evaluate retinal pathologies in the periphery.

10

Graph-based segmentation with homogeneous hue and texture vertices

88%

Ngo L. , Han J.-H.

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tom Vol. 51, nr 4

541--549

EN

This work presents an automated segmentation method, based on graph theory, which processes superpixels that exhibit spatially similarities in hue and texture pixel groups, rather than individual pixels. The graph shortest path includes a chain of neighboring superpixels which have minimal intensity changes. This method reduces graphics computational complexity because it provides large decreases in the number of vertices as the superpixel size increases. For the starting vertex prediction, the boundary pixel in first column which is included in this starting vertex is predicted by a trained deep neural network formulated as a regression task. By formulating the problem as a regression scheme, the computational burden is decreased in comparison with classifying each pixel in the entire image. This feasibility approach, when applied as a preliminary study in electron microscopy and optical coherence tomography images, demonstrated high measures of accuracy: 0.9670 for the electron microscopy image and 0.9930 for vitreous/nerve-fiber and inner-segment/outer-segment layer segmentations in the optical coherence tomography image.

11

Retained subretinal perfluorocarbon in multimodal image

88%

Guzmán Almagro E. , Cobo Soriano R. , Fuentes-Vega I. , Fernández Hortelano A. , González Martin-Moro J.

OphthaTherapy

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2021

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tom 8

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nr 2

87-91

EN

Introduction: Retained subretinal perfluoro-n-octane droplets occur in nearly 1% of the procedures. When subretinal cystoid cavities are registered, differential diagnosis including this condition is needed. Clinical case: A 77-year-old male presented three small bubbles of perfluoro-n-octane under the papillomacular bundle after vitrectomy due to a retina redetachment, evidenced by multimodal image. Conclusions: Multimodal image can help to diagnose this condition. There are several signs that can support this diagnosis. If visual acuity is threatened, removing the bubbles is mandatory, accepting risks.

12

Hyperreflective dots in optical coherence tomography

75%

Paczwa K. , Szabelska P. , Rerych M. , Różycki R. , Gołębiewska J.

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nr 3

175-179

EN

Optical coherence tomography is a non-invasive and repeatable imaging method of posterior segment of the eye used in medical practice. Hyperreflective dots visible in OCT scans have been reported in various retinal diseases such as age-related macular degeneration, diabetic macular edema, retinal vein occlusion and central serous chorioretinopathy. In the future, HRDs may become a useful biomarker in making treatment decision and monitoring ocular conditions among the patients with mentioned diseases.

13

Wczoraj, dziś i jutro polskiej radiologii

75%

Skrzyński W.

Inżynier i Fizyk Medyczny

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2013

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tom Vol. 2, nr 4

207--209

PL

W jednym z tegorocznych numerów „Inżyniera i Fizyka Medycznego” ukazał się artykuł o „(nie) znanej radiologii” [1]. Jego autorka w interesujący sposób przybliżyła czytelnikom dzieje polskiej radiologii – od jej początków, przez trudne lata II wojny światowej i PRL-u, aż po dzień dzisiejszy – a także perspektywy na przyszłość. Podążając tym samym tropem, chciałbym przypomnieć kilka faktów z pierwszych lat istnienia radiologii.

14

Światłowodowa koherentna tomografia optyczna (OCT) w zastosowaniach technicznych

75%

Maciejewski M. , Strąkowski M. , Pluciński J. , Kosmowski B. B. , Jędrzejewska-Szczerska M. , Hypszer R.

Elektronika : konstrukcje, technologie, zastosowania

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2005

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tom Vol. 46, nr 11

24-25

PL

Koherentna tomografia optyczna (ang. Optical Coherence Tomography - OCT) jest szybko rozwijającą się metodą obrazowania przekrojów wewnętrznych struktur. Pierwotnie używana do celów biomedycznych, może znaleźć szerokie zastosowanie do badań materiałowych. Jest to uniwersalna technika pomiarowa charakteryzująca się dużą rozdzielczością (rzędu pojedyńczych mikrometrów) połączoną z możliwością obrazowania optycznych ośrodków silnie rozpraszających światło. W artykule przedstawiono możliwe zastosowania OCT do pomiarów technicznych oraz uzyskane wstępne wyniki badań przeprowadzonych na próbkach materiałów warstwowych silnie rozpraszających światło.

EN

Optical coherence tomography (OCT) is rapidly developing method for internal structures imaging. First used in biomedical applications, it can be also applicable for technical materials investigation. It is universal measuring technique with high resolution (single micrometers) combined with possibility of imaging highly scattering media. The article presents possible optical coherence tomography applications to technical measurements and preliminary measurements of highly scattering layered materials.

15

Common path optical coherence tomography with electronic feedback for improved sensitivity

75%

Alsnaie K.

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tom Vol. 53, nr 3

495--504

EN

Optical coherence tomography (OCT) imaging has become a useful tool in medical diagnosis over the past 25 years, because of its ability to visualize intracellular structures at high resolution. The main objective of this work is to add electronic feedback to the optical coherence tomography setup to increase its sensitivity. Noise added to the measured interferogram obscures some details of examined tissue layered structure. Adjusting signal power level in such a way to improve signal-to-noise ratio can help to enhance image quality. Electronic feedback is added to enhance system sensitivity. A logarithmic amplifier is included in the OCT setup to automatically adapt signal level. Moreover, the resolution of the optical spectrum analyzer is controlled according to the farthest layer detected in the A-scan. These techniques are tested showing an improvement in obtained image of a human nail.

16

Zastosowanie interferometrii niskokoherentnej do jednoczesnego pomiaru grubości i współczynnika załamania struktur warstwowych

63%

Pluciński J. , Strąkowski M. , Kosmowski B. B.

Elektronika : konstrukcje, technologie, zastosowania

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2010

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tom Vol. 51, nr 6

136-139

PL

W pracy przedstawiono techniki oparte na interferometrii niskokoherentnej jednoczesnego pomiaru współczynnika załamania i grubości struktur warstwowych. Zaproponowano dwie metody: pierwsza oparta jest na pomiarze położenia górnej powierzchni granicznej warstwy i jej grubości optycznej (położenie dolnej powierzchni granicznej powinno być znane wcześniej); druga oparta jest na wykorzystaniu dynamicznego ogniskowania wiązki laserowej. Przeprowadzone testy pokazały, że możliwy jest jednoczesny pomiar grubości geometrycznej warstwy z dokładnością 1µm i współczynnika załamania z dokładnością lepszą niż 0,01.

EN

The paper presents a technique based on Iow-coherence interferometry for simultaneous measurement of refractive index and thickness of layered structures. Two methods are proposed: the first one is based on the measurement of the position of the upper boundary surface of the layer and its optical thickness (the position of the Iower boundary surface of the layer should be known in advance), the second one is based on dynamie focusing of the laser beam that is used in the measuring system. Performed tests have shown that it is possible to simultaneously measure the geometrie thickness with the accuracy of 1 µm, and the refractive index of better than 0.01.

17

Imaging the retinal and choroidal vasculature using Spatio-Temporal Optical Coherence Tomography (STOC-T)

63%

Liżewski K. , Tomczewski S. , Borycki D. , Węgrzyn P. , Wojtkowski M.

Biocybernetics and Biomedical Engineering

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2024

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tom Vol. 44, no. 1

95--104

EN

Spatio-Temporal Optical Coherence Tomography (STOC-T) is a novel imaging technique using light with controlled spatial and temporal coherence. Retinal images obtained using the STOC-T system maintain high resolution in all three dimensions, on a sample of about 700 μm, without the need for mechanical scanning. In the present work, we use known data processing algorithms for optical coherence tomography angiography (OCTA) and modify them to improve the rendering of the vasculature in the human retina at different depths by introducing the angio STOC-T method. The algorithms are primarily sensitive to the strong signal phase variance corresponding to the appearance of a wide Doppler band in STOC-T signals obtained for millisecond exposure times. After using STOC-T angiography, we can render high contrast images of the choroid.

18

Computer aided diagnosis of diabetic macular edema in retinal fundus and OCT images: A review

63%

Pavithra K. C. , Kumar P. , Geetha M. , Bhandary S. V.

Biocybernetics and Biomedical Engineering

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2023

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tom Vol. 43, no. 1

157--188

EN

Diabetic Macular Edema (DME) is a potentially blinding consequence of Diabetic Retinopathy (DR) as well as the leading cause of vision loss in diabetics. DME is characterized by a buildup of extracellular fluid inside the macula through hyperpermeable vessels. The presence of DME can be spotted at any level of DR with varying degrees of severity using prominent imaging modalities such as Color Fundus Photography (CFP) and Optical Coherence Tomography (OCT). Computerized approaches for screening eye disorders appear to be beneficial, as they provide doctors with detailed insights into abnormalities. Such a system for the evaluation of retinal images can function as a stand-alone disease monitoring system. This review reports the state-of-art automated DME detection methods with traditional Machine Learning (ML) and Deep Learning (DL) techniques employing retinal fundus or OCT images. The paper provides a list of public retinal OCT and fundus imaging datasets for DME detection. In addition, the paper describes the dynamics of advancements in presented methods adopted in the past along with their strengths and limitations to highlight the insufficiencies that could be addressed in future investigations.

19

Wpływ oddziaływania wiązki laserowej na skłonność tkanin poliestrowych do pilingu

63%

Korzeniewska E. , Walczak M. , Sekulska-Nalewajko J. , Gocławski J.

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2019

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tom R. 95, nr 1

73--76

PL

W artykule opisano wpływ modyfikacji powierzchni tkanin poliestrowych z wykorzystaniem wiązki laserowej. Ocenę tendencji do pilingu wykonano w oparciu o analizę obrazów 2D oraz 3D pozyskanych z wykorzystaniem optycznego tomografu koherentnego. Zaobserwowano, pozytywny wpływ obróbki laserowej na zmniejszającą się liczbę poluzowanych pojedynczych nitek wystających ponad powierzchnię tkaniny, a w efekcie końcowym na zmniejszenie powstającego niepożądanego pilingu.

EN

In the article the effect of surface modification of polyester fabrics using a laser beam has been described. Pilling tendency have been assessed based on the analysis of 2D and 3D images obtained from the optical coherence tomography. A positive effect of laser processing has been observed on the decreasing number of loosened single threads protruding above the surface of the fabric and in the result the reduction of the unwanted pilling.

20

Multi-scale local-global transformer with contrastive learning for biomarkers segmentation in retinal OCT images

63%

Liu X. , Ding Y. , Zhang Y. , Tang J.

Biocybernetics and Biomedical Engineering

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2024

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tom Vol. 44, no. 1

231--246

EN

Quantitative analysis of biomarkers in Optical Coherence Tomography (OCT) images plays an import role in the diagnosis and treatment of retinal diseases. However, biomarker segmentation in retinal OCT images is very hard due to the large variations in size and shape of retinal biomarkers, blurred boundaries, low contrast, and speckle interference. We proposed a novel Multi-scale Local-Global Transformer network (MsLGT-Net) for biomarker segmentation in retinal OCT images. The network combines the proposed Multi-scale Fusion Attention (MFA) module, Local-Global Transformer (LGT) module, and Contrastive Learning Enhancement (CLE) module to tackle the challenges of biomarker segmentation. Specifically, the proposed MFA module aims to enhance the network’s ability to learn multi-scale features of retinal biomarkers by effectively combining the local detail information and contextual semantic information of biomarkers at different scales, and improve the representation ability for different classes of biomarkers. The LGT module is designed to learn local and global information adaptively from multi-scale fused features to address the challenge of small biomarker segmentation. In addition, to distinguish features between different types of retinal biomarkers, we propose the CLE module to enhance the feature representation of different biomarkers. Our proposed method is validated on one public dataset and one local dataset. The experimental results show that the proposed method is more effective than other state-of-theart methods.