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Optische Koh?renztomografie
摘要： With telematics and technologies like “Digital Impression”, “CAD/CAM” or “3D-radiography” the digitalization has reached the dental practice by now. The desire for more efficient diagnostics is especially addressed by 3D-radiography. A noninvasive imaging technology with a considerable diagnostic potential is the optical coherence tomography. In this article, promising examples of OCT use in operative dentistry are presented that raise expectations of a wide range of applications of this innovative technology in dentistry.
关键词： restoration assessment,caries diagnosis,optical coherence tomography,restorative therapy with composite,monitoring,tomography
更新于2025-09-23 15:23:52
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[IEEE 2018 24th International Conference on Pattern Recognition (ICPR) - Beijing (2018.8.20-2018.8.24)] 2018 24th International Conference on Pattern Recognition (ICPR) - An Efficient Approach for Polyps Detection in Endoscopic Videos Based on Faster R-CNN
摘要： Polyps have long been considered as one of the major etiologies to colorectal cancer which is a fatal disease around the world, thus early detection and recognition of polyps plays a crucial role in clinical routines. Accurate diagnoses of polyps through endoscopes operated by physicians becomes a challenging task not only due to the varying expertise of physicians, but also the inherent nature of endoscopic inspections. To facilitate this process, computer-aid techniques that emphasize on fully-conventional image processing and novel machine learning enhanced approaches have been dedicatedly designed for polyp detection in endoscopic videos or images. Among all proposed algorithms, deep learning based methods take the lead in terms of multiple metrics in evolutions for algorithmic performance. In this work, a highly effective model, namely the faster region-based convolutional neural network (Faster R-CNN) is implemented for polyp detection. In comparison with the reported results of the state-of-the-art approaches on polyps detection, extensive experiments demonstrate that the Faster R-CNN achieves very competing results, and it is an efficient approach for clinical practice.
关键词： computer-aided diagnosis,deep learning,Faster R-CNN,polyp detection,endoscopic videos
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) - Houston, TX (2018.5.14-2018.5.17)] 2018 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) - Multi-core cable fault diagnosis using cluster time-frequency domain reflectometry
摘要： Guaranteeing the integrity and functionality of the control and instrumentation (C&I) cable system is essential in ensuring safe nuclear power plant (NPP) operation. When a fault occurs in a multi-core cable, it not only affects the signals of faulty lines but in fact, disturbs the rest as well due to crosstalk and noise interference. Therefore, this results in C&I signal errors in NPP operation and further leads to a rise in concern regarding the NPP operation. Thus, it is necessary for diagnostic technologies of multi-core C&I cables to classify the faulty line and detect the fault to assure the safety and reliability of NPP operation. We propose a diagnostic method that detects the fault location and faulty line in multi-core C&I cable using a clustering algorithm based on TFDR results. The faulty line detection clustering algorithm uses TFDR cross-correlation and phase synchrony results as input feature data altogether which can detect the faulty line and identify the fault point successfully. The proposed clustering algorithm is verified by experiments with two possible fault scenarios in NPP operation.
关键词： fault diagnosis,reflectometry,control and instrumentation cable,K-means clustering,crosstalk,time-frequency analysis
更新于2025-09-23 15:23:52
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Autofluorescence and spectral-domain optical coherence tomography of optic disk melanocytoma
摘要： The authors report fundus autofluorescence (FAF) and spectral-domain optical coherence tomography (OCT ) findings of two consecutive patients who presented with optic disk melanocytoma (ODM). A retrospective study was performed by reviewing medical records and ophthalmic imaging examinations. Optical coherence tomography findings were sloped and brightly reflective anterior tumor surface, adjacent retinal desorganization and abrupt posterior optical shadowing. Vitreous seeds were found in one patient. Fundus autofluorescence revealed outstanding hypoautofluorescence at the tumor area and isoautofluorescence at the remaining retina. Optical coherence tomography findings of the reported cases are consistent with those reported in the reviewed literature. Fundus autofluorescence has been used in the assessment of choroidal melanocytic tumors, but not yet in melanocytomas. We assume that this is the first report of these findings and believe that when its pattern has become clearly defined, fundus autofluorescence will be a useful tool to avoid misdiagnosis in suspicious cases and for follow-up.
关键词： Melanoma/diagnosis,Female,Adult,Male,Case reports,Optic nerve neoplasms/diagnosis,Fluorescein angiography,Humans,Tomography, optical coherence
更新于2025-09-23 15:22:29
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Intracoronary Imaging
摘要： Coronary angiography represents both the gold standard for diagnosis of coronary artery disease and the main guidance for percutaneous coronary intervention (PCI). Yet, coronary angiography is well known to not be optimal in appreciating the whole spectrum of lesions that may cause clinical problems in patients with coronary artery disease. Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) represent the 2 contemporary invasive intracoronary imaging modalities aimed at improving the detection of coronary details. Their potential is extraordinary but their use for improving coronary disease diagnosis is not standardized. Moving from diagnosis to treatment, PCI based on drug-eluting stent (DES) implantation often requires a series of manipulations with different techniques and devices. Last generation DES types have similar technical features and share a comparable ability to scaffold coronary lesions. Not surprisingly, lesion complexity is known to be associated with increased procedure challenges that may be tackled by different strategies. The selection of devices and the assessment of appropriate DES implantation may be based on either angiography or intracoronary imaging techniques like IVUS or OCT. Both techniques have evolved over time and offer the possibility to see details of coronary lesions and stent/vessel interactions that are impossible to be captured and measured by angiography. So far, thousands of studies with different designs have been performed, but they have not been able to make interventional cardiologists act in a homogeneous way. Consequently, intravascular imaging is selected on the basis of individual yield, with an impressive variability across different countries and operators. Reimbursement issues are part of the game but do not entirely explain the overall underutilization of intravascular imaging (especially in Western countries where a lot of expensive devices are routinely incorporated in interventional practice). In reality, the application of intracoronary imaging adds complexity to PCI, requires adequate technical skills, and by itself does not necessarily improve the clinical outcome. As compared with angiography guidance, IVUS and OCT are able to provide (in real time) many more coronary details. Such angiographically invisible details need to be recognized by the operator to properly react to improve the clinical outcome of treated patients. Because of the impressive amount of details and possible measures/cutoffs, the identification of both impactful features (deserving attention) and best reactions (additional technical steps with corrective efficacy) is pivotal. Yet, data collected by IVUS studies have not been concordant and this has resulted in overall limited clinical penetration: many catheterization laboratories are actually working without any access to intracoronary imaging. Furthermore, although rare, imaging catheter-related complications may occur so that a safety issue has to be considered any time the expected benefit is not well established in clinical practice. On the bases of these concepts, it is evident that the intracoronary imaging clinical impact may come from the correct identification and appropriate processing of those details that may help (1) to improve the PCI strategy (technique/device selection, that is, PCI planning) and (2) to facilitate the achievement of improved stenting result (ie, PCI optimization). As shown in the Figure, among all the information captured by intracoronary imaging, a limited series of imaging-based pre-PCI findings can be easily incorporated in the PCI planning (lesion preparation and stent selection). Similarly, some key intra-PCI findings (stent underexpansion, stent edge dissections, and strut malapposition) can be searched in order to optimize the stent implantation result. The feasibility of this approach is supported by the daily experience of many high volume centers. Yet, the overall clinical impact of image guidance in PCI is still unrecognized, and large studies in the field are needed. Recently-collected data started shedding new light on both IVUS and OCT. The large study by Maehara et al, although not randomized, allowed to run a propensity-matched comparison between thousands of IVUS-guided and angiography-guided procedures. IVUS use was associated with different procedure conduction and reduced major adverse events incidence at up to 2 years. Of note, the clinical benefit comprised significant improvements of hard end points, namely stent thrombosis, myocardial infarction, and cardiac mortality. Such results fit well with the recent ULTIMATE prospective randomized trial (Intravascular Ultrasound Guided Drug Eluting Stents Implantation in 'All-Comers' Coronary Lesions). The ULTIMATE investigators randomized 1448 all-comer patients who required DES implantation to either IVUS guidance or angiography guidance. As compared with angiography, randomization to IVUS guidance was associated with different procedure course (higher contrast administration, larger and longer stents, and higher inflation pressures) and warranted lower target vessel failures with IVUS at 12 months. OCT, as compared with IVUS, represents a younger technique, but data are growingly been collected because it has the appeal of offering higher resolution. The specific image generation process of OCT translates into the need of dedicated experience but has the potential for shorter learning curve. The possible clinical impact of OCT use in PCI guidance has been started to be highlighted by the results of the CLI-OPCI II study (Centro per la Lotta Contro l'Infarto-Optimisation of Percutaneous Coronary Intervention II). In this large registry, specific definitions for OCT features of suboptimal stent results were found to be independently associated with adverse clinical outcome after PCI. For sure, more complex PCIs (where the risk of stent thrombosis and restenosis is higher), are expected to benefit more from PCI refinements. Thus, two large prospectively randomized trials (OCTOBER, and ILUMIEN IV, and URL: https://www.clinicaltrials.gov. Unique identifier: NCT03507777) comparing OCT and angiographic guidance are actually ongoing and have been powered to explore the benefit of OCT guidance (using rigorous OCT-based PCI optimization algorithms) in, respectively, bifurcated lesions and complex patients. In conclusion, intravascular imaging modalities are entering a new era because the recently collected data seem to show new thresholds and targets for PCI planning and optimization. Thus, IVUS and OCT are going to become the ideal glasses that interventional cardiologists should wear anytime something looks unclear before, during or after PCI. Appropriate education, standardization of operative protocols and definitions of best clinical settings for application represent the future challenges for the intravascular imaging clinical implementation.
关键词： intravascular ultrasound,angiography,myocardial infarction,Editorials,diagnosis,optical coherence tomography,coronary artery disease,percutaneous coronary intervention
更新于2025-09-23 15:22:29
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Faulty elements diagnosis of phased array antennas using a generative adversarial learning-based stacked denoising sparse autoencoder
摘要： Diagnosis of faulty elements in a linear phased array antenna is of great importance in the wireless communication field which has been received increasing attention. As a result of element or elements failure in the linear phased array antennas, the whole radiation pattern will suffer from high side lobe levels, wide bandwidth and unexpected nulls. To this end, we suggest a novel approach by combining the generative adversarial learning and the stacked denoising sparse autoencoder to determine the location of the faulty elements in antennas. The suggested approach can learn discriminative features from radiation pattern images adaptively and automatically with less expert knowledge. Meanwhile, the suggested approach is able to overcome the strong noise, the high dimensional size of the radiation pattern and the small fault samples. In this regard, the suggested approach possesses superiority in discriminant capability in contrast to the existing related approaches.
关键词： stacked denoising sparse autoencoder,phased array antennas,Faulty elements diagnosis,generative adversarial learning
更新于2025-09-23 15:22:29
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[ACM Press the 3rd International Conference - Seoul, Republic of Korea (2018.08.22-2018.08.24)] Proceedings of the 3rd International Conference on Biomedical Signal and Image Processing - ICBIP '18 - Automatic Detection of Cell Regions in Microscope Images Based on BFED Algorithm
摘要： Circulating tumor cells (CTC) attract attention as a biomarker that can evaluate cancer metastasis and therapeutic effects. The CTC exists in the blood of cancer patients, so pathologists analyze blood by using a fluorescence microscope. However, manual analysis by pathologists is hard-work since the number of CTC to substances contained in the blood is very few and the cell regions are often unclear depending on shooting environments. In addition, there are few studies on automatic identification of CTC. In this paper, we develop an automatic detection method of cell regions in microscope images based on bacterial foraging-based edge detection (BFED) algorithm to analyze CTC. In the first step, we detect the initial cell regions by BFED algorithm. Second, we identify whether the region is a single cell or multiple cells come in connect with other cell(s) by SVM. Third, when a cell is connected with other one, we separate the connecting cells by branch and bound algorithm and obtain the final cell regions. We applied our proposed method to 1680 microscopy images (6 cases). The experimental results demonstrate that the proposed method has a true positive rate of 93.9% and a false positive 1.29 /case.
关键词： Saliency map,Computer aided diagnosis,Support vector machine,Branch and bound algorithm,Circulating tumor cells,BFED algorithm
更新于2025-09-23 15:22:29
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A Novel Stereo Vision Measurement System Using Both Line Scan Camera and Frame Camera
摘要： In the product surface defect detection system, the detection accuracy can be greatly improved if the surface grayscale image and depth image can be adopted simultaneously. Existing 3-D cameras have the problem in precise registration of 2-D images and 3-D data, which results in inflexibility and inevitable error in practical vision tasks. Hence, we propose a novel stereo vision measurement system which is able to simultaneously acquire registered scan grayscale images and depth images without special data registration algorithm as well as the calibration method. The proposed measurement system mainly consists of a line laser system, a line scan camera, and a frame camera. The line scan camera captures clear images of objects illuminated by the line laser. In addition, the line scan camera and the frame camera form a stereo vision sensor. In this case, the line laser stripe provides location feature of the matching point for frame camera. The epipolar constraint implements the matching process between the line scan camera and the frame camera. Finally, the stereo vision measurement model is utilized to realize the 3-D coordinate reconstruction, and the z-axis coordinate is used to generate depth image. The proposed system can simultaneously obtain the image and depth information corresponding to each pixel by means of a push sweep. In the experiment, the measurement system can achieve the accuracy of 0.13 mm within a measurement range of 500 mm × 300 mm × 200 mm.
关键词： Fault diagnosis,machine vision,visual system,measurement,laser measurement applications
更新于2025-09-23 15:22:29
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Quantification of the Changes in the Openness of the Major Temporal Arcade in Retinal Fundus Images of Preterm Infants With Plus Disease
摘要： PURPOSE. We tested the hypothesis that the openness of the major temporal arcade (MTA) changes in the presence of plus disease, by quanti?cation via parabolic modeling of the MTA, as well as measurement of an arcade angle for comparative analysis. Such analysis could assist in the detection and treatment of progressive retinopathy of prematurity. METHODS. Digital image processing techniques were applied for the detection and modeling of the MTA via a graphical user interface (GUI) to quantify the openness of the MTA. An arcade angle measure, based on a previously proposed method, also was obtained via the GUI for comparative analysis. The statistical signi?cance of the differences between the plus and no-plus cases for each parameter was analyzed using the P value. The area (Az) under the receiver operating characteristic curve was used to assess the diagnostic performance of each feature. RESULTS. The temporal arcade angle measure and the openness parameter of the parabolic model were used to perform discrimination of plus versus no-plus cases. Using a set of 19 cases with plus and 91 with no plus disease, Az ? 0.70 was obtained using the results of dual-parabolic modeling in screening for plus disease. The arcade angle measure provided comparable results with Az ? 0.73. CONCLUSIONS. Using our proposed image analysis techniques and software, this study demonstrates, for the ?rst time to our knowledge, that the openness of the MTA decreases in the presence of plus disease.
关键词： plus disease,computer-aided diagnosis,retinopathy of prematurity,major temporal arcade,digital image analysis
更新于2025-09-23 15:22:29
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Effectiveness of a Qualitative Approach Toward Evaluating OCT Imaging for Detecting Glaucomatous Damage
摘要： Purpose: The purpose of this study was to determine whether a qualitative approach toward evaluating optical coherence tomography (OCT) imaging improves the ability to detect glaucomatous damage compared to a conventional metric of global circumpapillary retinal nerve fiber layer (cpRNFL) thickness. Methods: A total of 394 healthy eyes and 272 glaucoma eyes were evaluated. Glaucoma eyes were categorized as perimetric (156 eyes) based on a history of three or more consecutive abnormal 24-2 visual field tests or suspected glaucoma if they did not (116 eyes). Customized one-page reports derived using OCT volume scans of the optic disc and macula from these eyes were qualitatively graded for the probability of optic neuropathy affecting the eye. Results: The sensitivity of detecting perimetric glaucoma eyes with the global circumpapillary RNFL thickness metric and qualitative evaluation of the OCT imaging results were 86.5% and 95.5% at a specificity of 95%, being significantly higher for the latter (P < 0.001). There were seven eyes with perimetric glaucoma missed by the qualitative evaluation. Based upon examination of all available visual fields, at least four of these seven eyes had visual fields that either improved or had abnormalities that were inconsistent over time or with patterns of glaucomatous damage. Conclusions: Qualitative evaluation of OCT imaging results allows glaucoma eyes with repeatable visual field abnormalities to be detected with a high level of accuracy, performing better than a conventional summary metric of global cpRNFL thickness.
关键词： diagnosis,glaucoma,qualitative,optical coherence tomography
更新于2025-09-23 15:22:29