• Journal of the Optical Society of Korea
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• 제18권3호
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• pp.230-235
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• 2014

Two-step quadrature phase-shifting digital holography based on the calculated intensity of a reference wave is proposed. In the Mach-Zehnder interferometer (MZI) architecture, the method only records two quadrature-phase holograms, without reference-wave intensity or object-wave intensity measurement, to perform object recoding and reconstruction. When the reference-wave intensity is calculated from the 2D correlation coefficient (CC) method that we presented, the clear reconstruction image can be obtained by some specific algorithm. Its feasibility and validity were verified by a series of experiments with 2D objects and 3D objects. The presented method will be widely used in real-time or dynamic digital holography applications.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제25권1호
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• pp.87-91
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• 2022

Ingestion of foreign bodies (FBs) is a common phenomenon among young children. Plain radiography is the first step diagnostic modality to detect the radio-opaque FBs. And computed tomography has been recommended by several guidelines as useful modalities for diagnosing ingested FBs. However, there is a risk of radiation exposure, making it burdensome to use in asymptomatic patients. Ultrasound (US) is not a commonly used technique for diagnosing ingested foreign bodies. However, US can provide real-time imaging with good resolutions without radiation exposure in pediatric patients. Herein, we report two pediatric cases of metallic foreign body ingestion that were successfully diagnosed using US for localizing foreign bodies. This study indicates that US may be used as an alternative method for detecting the localization of metallic foreign bodies in the gastrointestinal tract without exposure of radiation, particularly in pediatric patients.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권11호
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• pp.3479-3492
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• 2022

Longitudinal quantification of brain changes due to development, aging or disease plays an important role in the filed of personalized-medicine applications. However, due to the temporal variability in shape and different imaging equipment and parameters, estimating anatomical changes in longitudinal studies is significantly challenging. In this paper, a longitudinal Magnetic Resonance(MR) brain image segmentation algorithm proposed by combining intensity information and anisotropic smoothness term which contain a spatial smoothness constraint and longitudinal consistent constraint into a variational framework. The minimization of the proposed energy functional is strictly and effectively derived from a fast optimization algorithm. A large number of experimental results show that the proposed method can guarantee segmentation accuracy and longitudinal consistency in both simulated and real longitudinal MR brain images for analysis of anatomical changes over time.

• Journal of Yeungnam Medical Science
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• 제39권3호
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• pp.190-199
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• 2022

Ultrasound-guided injection is useful for managing thoracic spine and chest wall pain. With ultrasound, pain physicians perform the injection with real-time viewing of major structures, such as the pleura, vasculature, and nerves. Therefore, the ultrasound-guided injection procedure not only prevents procedure-related adverse events but also increases the accuracy of the procedure. Here, ultrasound-guided interventions that could be applied for thoracic spine and chest wall pain were described. We presented ultrasound-guided thoracic facet joint and costotransverse joint injections and thoracic paravertebral, intercostal nerve, erector spinae plane, and pectoralis and serratus plane blocks. The indication, anatomy, Sonoanatomy, and technique for each procedure were also described. We believe that our article is helpful for clinicians to conduct ultrasound-guided injections for controlling thoracic spine and chest wall pain precisely and safely.

• 대한방사성의약품학회지
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• 제8권1호
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• pp.39-44
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• 2022

The development of methods for the inert and stable radiohalogenation of targeted radiopharmaceuticals is a prerequisite for real-time diagnosis and therapy using radiohalogenated radiopharmaceuticals. Radiohalogenated carboranes demonstrate superior stability in vivo and versatile applications compared with directly labeled tyrosine analogues or synthetically modified organic compounds. Herein, we focus on the most common approaches for the radioiodination (¹²³l, ¹²⁴l, ¹²⁵l, and ¹³¹l) of carborane derivatives.

• Clinical Endoscopy
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• 제55권5호
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• pp.594-604
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• 2022

Over the past decade, technological advances in deep learning have led to the introduction of artificial intelligence (AI) in medical imaging. The most commonly used structure in image recognition is the convolutional neural network, which mimics the action of the human visual cortex. The applications of AI in gastrointestinal endoscopy are diverse. Computer-aided diagnosis has achieved remarkable outcomes with recent improvements in machine-learning techniques and advances in computer performance. Despite some hurdles, the implementation of AI-assisted clinical practice is expected to aid endoscopists in real-time decision-making. In this summary, we reviewed state-of-the-art AI in the field of gastrointestinal endoscopy and offered a practical guide for building a learning image dataset for algorithm development.

• 대한임베디드공학회논문지
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• 제8권2호
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• pp.121-128
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• 2013

There have been various research efforts for pedestrian recognition in embedded imaging systems. However, many suffer from their heavy computational complexities. SVM classification method has been widely used for pedestrian recognition. The reduction of candidate region is crucial for low-complexity scheme. In this paper, We propose a real time HOG based pedestrian detection system on GPU which images are captured by a pair of cameras. To speed up humans on road detection, the proposed method reduces a number of detection windows with disparity-search and near-search algorithm and uses the GPU and the NVIDIA CUDA framework. This method can be achieved speedups of 20% or more compared to the recent GPU implementations. The effectiveness of our algorithm is demonstrated in terms of the processing time and the detection performance.

• 디지털콘텐츠학회 논문지
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• 제19권4호
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• pp.757-770
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• 2018

열화상 영상기반 감시 시스템에서 전경추출은 매우 중요한 단계이다. 전경추출단계는 계산시간과 메모리 사용측면에서 시스템의 실시간 처리가 매우 효율적이어야 한다. 그러나 이러한 효율성은 ROI 탐지의 정확도와 매우 연관되어 있다. 본 논문에서 열화상 비디오 처리를 위하여 새로운 히스토그램 빈에 기반하여 배경과 전경을 분리하기 위한 두 가지 방법을 제시하는데, 이는 임의의 주어진 환경에서 열화상영상의 시간상에서 일관성을 갖는 다는 점과, 이러한 성질이, 간단한 시간축 메디안 필터링에 비하여 80%이상의 메모리를 절감할 수 있다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.399-402
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• 2005

For efficient and accurate diagnosis of ultrasound images, the time gain compensation (TGC) and dynamic range (DR) control of the ultrasound echo signal are important. TGC is for compensating the attenuation of the ultrasound echo signal along the depth, and DR is used to control the image contrast. In this paper, we propose an algorithm for finding the optimized values of TGC and DR automatically. For TGC, the degree of compensation is determined along the depth based on the effective attenuation estimation of ultrasound signal. For DR optimization, we introduce a novel cost function on the basis of the characteristics of ultrasound image, which provides the minimum value at the optimal DR. Experiments have been performed by applying the proposed algorithm to a real US imaging system. The results show that the algorithm automatically can determine the values of TGC and DR in realtime so that the subjective quality of the corresponding US image may be good enough for diagnosis.

• 대한의용생체공학회:의공학회지
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• 제19권1호
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• pp.9-18
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• 1998

본 논문은 초음파 의용 영상에서 인체내의 매질의 초음파 속도의 불균일에 의한 focusing의 저하에 대하여 논하였다. simulation환경으로, 인체 내의 매질 중 속도 값이 가장 큰 차이가 나는 지방(fat)을 일정한 두께로 모델링하였다. 그리고 초음파 빔의 굴절에 의한 진행경로의 변화와 속도차이에 따른 시간지연에 의한 해상도 저하를 구하였다. 그리고 이를 보상하는 방법으로, 보상에 계산량이 많이 필요한 굴절을 무시하고, 속도차에 의한 시간지연만 보상하는 방법을 제안하였다. 제안한 방법을 적용할 경우 현재의 실시간 디지털 focusing 시스템에서 쉽게 구현 가능하다.