117 results on '"Hyunseung Cho"'
Search Results
2. Development of a Chest-Belt-Type Biosignal-Monitoring Wearable Platform System
- Author
-
Jin-Hee Yang, Je-Wook Chae, Sang-Min Kim, Joo Hyeon Lee, Hwi-Kuen Kwak, Jeong-Whan Lee, and Hyunseung Cho
- Subjects
020205 medical informatics ,business.industry ,Computer science ,010401 analytical chemistry ,technology, industry, and agriculture ,Wearable computer ,Dual layer ,02 engineering and technology ,Heart activity ,01 natural sciences ,Signal ,0104 chemical sciences ,parasitic diseases ,0202 electrical engineering, electronic engineering, information engineering ,Biosignal ,Electrical and Electronic Engineering ,business ,Strain gauge ,Computer hardware - Abstract
The purpose of this study was to develop a wearable platform system that can detect and acquire a soldier’s biosignals (i.e., heart activity signal, respiration rate, etc.) in a nonrestrained, unconscious manner. These detected biosignals are transmitted to a processing device to analyze and monitor the soldier’s physical status. To achieve this, textile-based heart activity electrodes and a strain gauge sensor for the respiration signal measurement were developed, and their performances in detecting each signal were verified. These sensors were embedded in a chest belt to design a wearable platform that can simultaneously measure heart activity and respiration signals. The sensor part of the chest belt has a dual layer structure to detect high-quality signals. Stretch fabric was used on the outer layer and a respiration sensor was attached to the belt. On the inside layer, a non-stretch fabric was used as the base fabric and a heart activity-sensing electrode, that is capable of taking measurements using a modified lead-II heart activity signal induction method, was embroidered onto the fabric. Subjects were asked to wear the chest belt, and a biosignal processor module was attached to verify the system’s performance while simultaneously acquiring the heart activity and respiration signals. More specifically, it was confirmed that the two signals were detected in a stable. It is expected that the biosignal-monitoring wearable platform system developed in this study will be able to effectively analyze and monitor soldiers’ biosignals.
- Published
- 2020
- Full Text
- View/download PDF
3. Sensing efficiency of three-dimensional textile sensors with an open-and-close structure for respiration rate detection
- Author
-
Hyunseung Cho, Jin-Hee Yang, Soo-hyun Oh, Hyeok-Jae Lee, Hwy-Kuen Kwak, Joo Hyeon Lee, Jeong-Whan Lee, and Je-Wook Chae
- Subjects
Polymers and Plastics ,Textile sensors ,Computer science ,010401 analytical chemistry ,Electronic engineering ,Chemical Engineering (miscellaneous) ,02 engineering and technology ,Wearable systems ,021001 nanoscience & nanotechnology ,0210 nano-technology ,Respiration rate ,01 natural sciences ,0104 chemical sciences - Abstract
The strain-gauge type textile sensors adopted in many studies on respiration-sensing wearable systems have been reported to have two major limitations that result in reduced sensing accuracy and insufficient durability of the sensor. The two limitations are the inability to accurately monitor the changes in the three-dimensional (3D) body contour during changes in the respiration cycle and the frequent occurrence of baseline drifts. To solve these issues, this study proposes new types of textile respiration rate sensors with a 3D structure, which measure the respiration rate based on the variation in the size of the contacting section’s surface during respiration, rather than the changes in the length of the sensor, as in existing strain-gauge type sensors. Firstly, the sensing signals were analyzed based on morphology and size measurements. Then, the sensing reliability of three respiration rate sensor types, namely the no-filler, 3D hard, and 3D soft types, was analyzed by comparing their measurements with those of the SS5LB. Finally, the reproducibility and baseline drifts of the sensors’ measurements were evaluated by taking and comparing repeated measurements. As a result, the consistency of the sensing signals of the SS5LB and those of the two types of 3D sensors was higher than those of the no-filler type sensor, and the 3D soft type sensor had the highest reliability and reproducibility among the three new types of sensors. The result showed relatively reduced baseline drifts in the two types of 3D sensors.
- Published
- 2020
- Full Text
- View/download PDF
4. Effect of Fabric Sensor Type and Measurement Location on
- Author
-
Joo Hyeon Lee, Sang-Min Kim, Hyunseung Cho, Jin-Hee Yang, Hwi-Kuen Kwak, Su-Hyeon Oh, Hyeok-Jae Lee, Yun-Su Ko, Je-Wook Chae, Jeong-Hwan Lee, and Kang-Hwi Lee
- Subjects
Environmental Engineering ,Computer science ,Detection performance ,Respiratory monitoring ,Respiratory system ,Biomedical engineering - Published
- 2019
- Full Text
- View/download PDF
5. Dictionary-learning-based image deblurring for improving image performance in x-ray nondestructive testing
- Author
-
Do Yun Lee, Duhee Jeon, J.E. Park, Chang-Woo Seo, Woo-Sik Kim, S.Y. Park, H.W. Lee, Hyunseung Cho, Sangmook Kang, Kwang Soon Kim, Y. Lim, C.K. Park, Guna Kim, and Hyunwoo Lim
- Subjects
Physics ,Nuclear and High Energy Physics ,Deblurring ,Pixel ,business.industry ,Detector ,020206 networking & telecommunications ,02 engineering and technology ,Sparse approximation ,Signal ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Nondestructive testing ,0202 electrical engineering, electronic engineering, information engineering ,Computer vision ,Artificial intelligence ,Linear combination ,business ,Instrumentation ,Feature learning - Abstract
This study investigated a dictionary-learning (DL)-based image deblurring method for improving image performance in x-ray nondestructive testing. DL is a representation learning theory that aims to find a sparse representation of the input signal in the form of a linear combination of basic elements as well as those basic elements themselves. In this study, a DL-based algorithm was implemented, and a computational simulation and experiment were then performed to evaluate the algorithm’s effectiveness for image deblurring. The hardware system used in the experiment consisted of an x-ray tube with a focal spot size of 0.6 mm and a flat-panel detector with a pixel size of 100 μ m2. X-ray images of several electronic components were acquired at x-ray tube conditions of 80 kV p and 1.25 mAs. The image characteristics of the deblurred images generated by the DL-based algorithm were quantitatively evaluated in terms of intensity profile, universal-quality index, and noise power spectrum. Our results indicate that our DL-based image deblurring method effectively improves image performance in x-ray nondestructive testing.
- Published
- 2019
- Full Text
- View/download PDF
6. Low-dose single-energy material decomposition in radiography using a sparse-view computed tomography scan
- Author
-
C.K. Park, S.Y. Park, Seokyoon Kang, Hyunna Lee, Kyung-Rae Kim, Dai Woon Lee, Chang-Woo Seo, Wonjin Kim, Duhee Jeon, Jung Su Park, Hyunseung Cho, Y. Lim, H.Y. Lim, Moon-Gyu Lee, and Gwangmook Kim
- Subjects
Materials science ,medicine.diagnostic_test ,business.industry ,General Chemical Engineering ,Radiography ,010401 analytical chemistry ,Low dose ,Soft tissue ,Computed tomography ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,medicine ,0210 nano-technology ,business ,Material decomposition ,Instrumentation ,Dictionary learning ,Energy (signal processing) ,General Environmental Science ,Biomedical engineering - Abstract
Dual-energy material decomposition (DEMD) is a well-established theoretical x-ray technique that uses low- and high-kilovoltage radiographs to separate soft tissue and bone in radiography and compu...
- Published
- 2019
- Full Text
- View/download PDF
7. Layer Decomposition Learning Based on Discriminative Feature Group Split With Bottom-Up Intergroup Feature Fusion for Single Image Deraining
- Author
-
Yunseon Jang, Duc-Tai Le, Chang-Hwan Son, and Hyunseung Choo
- Subjects
Computer vision ,deep learning ,image deraining ,image detail maintenance ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Rain streaks impede image feature extraction, hindering the performance of computer vision algorithms such as pedestrian and lane detection in adverse weather conditions. Image deraining is crucial for enhancing reliability of such algorithms. However, detail and texture information of objects in background areas are often lost during the deraining process due to their structural similarity with rain streaks. To remove rain streaks effectively while preserving image details, we propose a novel layer decomposition learning network (LDLNet) to separate rain streaks and object details in rainy images. LDLNet consists of two parts: the discriminative group feature split (DGFS) and the group feature merging (GFM). DGFS utilizes sparse residual attention modules (SRAM) to capture spatial contextual features of rainy images, enhancing the network’s ability to understand the complex relationships between rain streaks and object details. In addition, DGFS employs the bottom-up intergroup feature fusion (BIFF) approach to aggregate multi-scale context information from continuous SRAMs, facilitating the decomposition of rainy images into discriminative feature groups. Subsequently, GFM integrates these feature groups by concatenating them, preserving the interdependent characteristics of clean backgrounds and rain layers. Experimental results reveal that the proposed approach achieves superior rain removal and detail preservation in both synthetic datasets and real-world rainy images compared to the state-of-the-art rain removal models.
- Published
- 2024
- Full Text
- View/download PDF
8. Self-Attention (SA)-ConvLSTM Encoder–Decoder Structure-Based Video Prediction for Dynamic Motion Estimation
- Author
-
Jeongdae Kim, Hyunseung Choo, and Jongpil Jeong
- Subjects
SA-ConvLSTM ,encoder–decoder ,video prediction ,spatiotemporal ,self-attention memory module ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Video prediction, which is the task of predicting future video frames based on past observations, remains a challenging problem because of the complexity and high dimensionality of spatiotemporal dynamics. To address the problems associated with spatiotemporal prediction, which is an important decision-making tool in various fields, several deep learning models have been proposed. Convolutional long short-term memory (ConvLSTM) can capture space and time simultaneously and has shown excellent performance in various applications, such as image and video prediction, object detection, and semantic segmentation. However, ConvLSTM has limitations in capturing long-term temporal dependencies. To solve this problem, this study proposes an encoder–decoder structure using self-attention ConvLSTM (SA-ConvLSTM), which retains the advantages of ConvLSTM and effectively captures the long-range dependencies through the self-attention mechanism. The effectiveness of the encoder–decoder structure using SA-ConvLSTM was validated through experiments on the MovingMNIST, KTH dataset.
- Published
- 2024
- Full Text
- View/download PDF
9. Influence of Detailed Structure and Curvature of Woven Fabric on the Luminescence Effect of Wearable Optical Fiber Fabric
- Author
-
Yun-Jung Oh, Hyunseung Cho, Jin-Hee Yang, Joo Hyeon Lee, and Hwy-Kuen Kwak
- Subjects
Environmental Engineering ,Materials science ,Optical fiber ,law ,Woven fabric ,Wearable computer ,Composite material ,Curvature ,Luminescence ,law.invention - Published
- 2018
- Full Text
- View/download PDF
10. Effect of the Configuration of Contact Type Textile Electrode on the Performance of Heart Activity Signal Acquisition for Smart Healthcare
- Author
-
Kang-Hwi Lee, Hyunseung Cho, Sin-Hye Kim, Jin-Hee Yang, Yun-Jung Oh, Sang-Min Kim, Jeong-Hwan Lee, Hye-Ran Koo, Hwy-Kuen Kwak, Yun-Su Ko, Su-Youn Park, and Joo Hyeon Lee
- Subjects
Environmental Engineering ,Computer science ,business.industry ,Electrical engineering ,Contact type ,Heart activity ,business ,Textile electrodes ,Signal acquisition - Published
- 2018
- Full Text
- View/download PDF
11. A blind-deblurring method based on a compressed-sensing scheme in digital breast tomosynthesis
- Author
-
Jong Sook Park, Duhee Jeon, Younghwan Lim, Dong-Hoon Lee, Hyunseung Cho, Kir-Young Kim, C.K. Park, Wonjin Kim, Changwoo Seo, Hyunna Lee, Hyun Chang Lim, J. Oh, Gwangmook Kim, Seokyoon Kang, Taeho Woo, and Seyeon Park
- Subjects
Scheme (programming language) ,Deblurring ,Mean squared error ,Computer science ,business.industry ,Mechanical Engineering ,Detector ,02 engineering and technology ,Digital Breast Tomosynthesis ,Atomic and Molecular Physics, and Optics ,030218 nuclear medicine & medical imaging ,Electronic, Optical and Magnetic Materials ,03 medical and health sciences ,0302 clinical medicine ,Compressed sensing ,0202 electrical engineering, electronic engineering, information engineering ,Breast examination ,020201 artificial intelligence & image processing ,Computer vision ,Artificial intelligence ,Electrical and Electronic Engineering ,Projection (set theory) ,business ,computer ,computer.programming_language - Abstract
Background and objective Digital breast tomosynthesis (DBT) is a well-established multiplanar imaging modality in breast examinations designed to overcome the limitations of conventional mammography. However, reconstructed DBT images from the acquired projection data are often limited in image performance due mainly to blur artifacts resulting from inherent aspects of imaging systems, including detector resolution and the finite focal spot of the x-ray tube. Methods We investigated an effective blind-deblurring method based on a compressed-sensing scheme in an attempt to solve the blurring problem in DBT. We implemented the proposed algorithm and performed a systematic simulation and an experiment to demonstrate its viability. In both simulation and experiment, all of the projection data were taken with a tomographic angle of θ = 32° and an angle step of Δθ = 2°. The proposed deblurring algorithm was then applied to the projection data before performing the common filtered-backprojection-based DBT reconstruction process. Results The deblurred projection images showed much better image performance compared with the blurred projection images, demonstrating the viability of the proposed blind-deblurring scheme in conventional radiography. The PSNR and RMSE characteristics of the deblurred DBT image improved by factors of approximately 1.63 and 0.37, respectively, compared with those of the blurred DBT image. Conclusions Our results indicate that the proposed blind-deblurring method was effective in reducing the blurring problem in both DBT and in conventional radiography, excluding additional measurement of the system response function.
- Published
- 2018
- Full Text
- View/download PDF
12. Development of Wearable Sensing and Feedback Product Design for Movement Monitoring
- Author
-
Hyunseung Cho, Kang-Hwi Lee, Hak-Su Jeon, Su-Youn Park, Jin-Hee Yang, Hyeong-Ik Choi, Jeong-Hwan Lee, and Joo Hyeon Lee
- Subjects
Environmental Engineering ,Product design ,Computer science ,Wearable sensing ,Human–computer interaction ,Movement (music) - Published
- 2018
- Full Text
- View/download PDF
13. Improvement of radiographic visibility using an image restoration method based on a simple radiographic scattering model for x-ray nondestructive testing
- Author
-
Duhee Jeon, Hyunseung Cho, C.K. Park, Woo-Sik Kim, Hunwoo Lee, Sang Young Park, Uikyu Je, Jung-Eun Park, Kwang Soon Kim, S.Y. Kang, Hyunwoo Lim, Younghwan Lim, Do Yun Lee, Taeho Woo, and Guna Kim
- Subjects
Computer science ,business.industry ,Scattering ,Mechanical Engineering ,Radiography ,Visibility (geometry) ,02 engineering and technology ,Condensed Matter Physics ,Object (computer science) ,030218 nuclear medicine & medical imaging ,Image (mathematics) ,03 medical and health sciences ,0302 clinical medicine ,Nondestructive testing ,0202 electrical engineering, electronic engineering, information engineering ,Superimposition ,020201 artificial intelligence & image processing ,General Materials Science ,Computer vision ,Artificial intelligence ,business ,Image restoration - Abstract
In conventional radiography, image visibility is often limited mainly due to the superimposition of the object’s structure under investigation and scattered x-rays. Several methods, including the antiscatter grid technique, the air-gap technique, and scatter correction methods using measurements, mathematical-physical modeling, or a combination of both, have been extensively investigated in an attempt to overcome these difficulties. However, these methods require special equipment, geometry, and extra work to measure the scatter characteristics. In this study, we propose a new image restoration method based on a simple radiographic scattering model in which the intensity of the scattered x-rays and the direct transmission function of a given object are estimated from a single x-ray image by using the dark-channel prior. We implemented the proposed algorithm and performed a systematic experiment by using a 450-kV industrial x-ray inspection system to demonstrate its viability for nondestructive testing. Our results indicated that the structure of the examined object was much more clearly visible in the restored image, considerably improving the radiographic visibility.
- Published
- 2018
- Full Text
- View/download PDF
14. Feasibility study on low-dosage digital tomosynthesis (DTS) using a multislit collimation technique
- Author
-
C.K. Park, Jung-Eun Park, Taeho Woo, Duhee Jeon, Guna Kim, Sang Young Park, Hyunwoo Lim, Hyunseung Cho, Hunwoo Lee, Do Yun Lee, Woo-Sik Kim, Kyung Sik Kim, Chang-Woo Seo, and S.Y. Kang
- Subjects
Physics ,Nuclear and High Energy Physics ,business.industry ,Image quality ,Collimator ,Tomosynthesis ,Collimated light ,030218 nuclear medicine & medical imaging ,law.invention ,03 medical and health sciences ,0302 clinical medicine ,Optics ,Compressed sensing ,Data acquisition ,Duty cycle ,law ,030220 oncology & carcinogenesis ,business ,Projection (set theory) ,Instrumentation - Abstract
In this study, we investigated an effective low-dose digital tomosynthesis (DTS) where a multislit collimator placed between the X-ray tube and the patient oscillates during projection data acquisition, partially blocking the X-ray beam to the patient thereby reducing the radiation dosage. We performed a simulation using the proposed DTS with two sets of multislit collimators both having a 50% duty cycle and investigated the image characteristics to demonstrate the feasibility of this proposed approach. In the simulation, all projections were taken at a tomographic angle of θ = ± 5 0 ° and an angle step of Δ θ = 2 ° . We utilized an iterative algorithm based on a compressed-sensing (CS) scheme for more accurate DTS reconstruction. Using the proposed DTS, we successfully obtained CS-reconstructed DTS images with no bright-band artifacts around the multislit edges of the collimator, thus maintaining the image quality. Therefore, the use of multislit collimation in current real-world DTS systems can reduce the radiation dosage to patients.
- Published
- 2018
- Full Text
- View/download PDF
15. A model-based radiography restoration method based on simple scatter-degradation scheme for improving image visibility
- Author
-
Taeho Woo, Hyunseung Cho, Jong Sook Park, Dong-Hoon Lee, C.K. Park, J. Oh, Hyun Chang Lim, Duhee Jeon, Hyunna Lee, Wonjin Kim, S.Y. Park, Seokyoon Kang, Won Jun Kang, Gwangmook Kim, Chang-Woo Seo, and Kir-Young Kim
- Subjects
Computer science ,business.industry ,Noise (signal processing) ,Mechanical Engineering ,Radiography ,Visibility (geometry) ,Grid ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,030218 nuclear medicine & medical imaging ,Electronic, Optical and Magnetic Materials ,Image (mathematics) ,010309 optics ,Reduction (complexity) ,03 medical and health sciences ,0302 clinical medicine ,0103 physical sciences ,Superimposition ,Computer vision ,Artificial intelligence ,Electrical and Electronic Engineering ,business ,Image restoration - Abstract
In conventional planar radiography, image visibility is often limited mainly due to the superimposition of the object structure under investigation and the artifacts caused by scattered x-rays and noise. Several methods, including computed tomography (CT) as a multiplanar imaging modality, air-gap and grid techniques for the reduction of scatters, phase-contrast imaging as another image-contrast modality, etc., have extensively been investigated in attempt to overcome these difficulties. However, those methods typically require higher x-ray doses or special equipment. In this work, as another approach, we propose a new model-based radiography restoration method based on simple scatter-degradation scheme where the intensity of scattered x-rays and the transmission function of a given object are estimated from a single x-ray image to restore the original degraded image. We implemented the proposed algorithm and performed an experiment to demonstrate its viability. Our results indicate that the degradation of image characteristics by scattered x-rays and noise was effectively recovered by using the proposed method, which improves the image visibility in radiography considerably.
- Published
- 2018
- Full Text
- View/download PDF
16. Application of a dual-resolution voxelization scheme to compressed-sensing (CS)-based iterative reconstruction in digital tomosynthesis (DTS)
- Author
-
Guna Kim, Hyunseung Cho, C.K. Park, J.E. Park, Duhee Jeon, Woo-Sik Kim, H.W. Lee, Taeho Woo, S.Y. Park, J.E. Oh, Do Yun Lee, Hyunwoo Lim, Kang Sangwoo, Kwang Soon Kim, and Uikyu Je
- Subjects
Physics ,Nuclear and High Energy Physics ,Iterative and incremental development ,Mean squared error ,business.industry ,Image quality ,Iterative method ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Iterative reconstruction ,computer.software_genre ,Tomosynthesis ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Compressed sensing ,Voxel ,030220 oncology & carcinogenesis ,Computer vision ,Artificial intelligence ,business ,Instrumentation ,computer - Abstract
In recent digital tomosynthesis (DTS), iterative reconstruction methods are often used owing to the potential to provide multiplanar images of superior image quality to conventional filtered-backprojection (FBP)-based methods. However, they require enormous computational cost in the iterative process, which has still been an obstacle to put them to practical use. In this work, we propose a new DTS reconstruction method incorporated with a dual-resolution voxelization scheme in attempt to overcome these difficulties, in which the voxels outside a small region-of-interest (ROI) containing target diagnosis are binned by 2 × 2 × 2 while the voxels inside the ROI remain unbinned. We considered a compressed-sensing (CS)-based iterative algorithm with a dual-constraint strategy for more accurate DTS reconstruction. We implemented the proposed algorithm and performed a systematic simulation and experiment to demonstrate its viability. Our results indicate that the proposed method seems to be effective for reducing computational cost considerably in iterative DTS reconstruction, keeping the image quality inside the ROI not much degraded. A binning size of 2 × 2 × 2 required only about 31.9% computational memory and about 2.6% reconstruction time, compared to those for no binning case. The reconstruction quality was evaluated in terms of the root-mean-square error (RMSE), the contrast-to-noise ratio (CNR), and the universal-quality index (UQI).
- Published
- 2018
- Full Text
- View/download PDF
17. Scout-view assisted interior digital tomosynthesis (iDTS) based on compressed-sensing theory
- Author
-
Hyunseung Cho, Guna Kim, Do Yun Lee, Minsik Lee, Hunwoo Lee, Sang Young Park, Taeho Woo, Changwoo Seo, Uikyu Je, Hyunwoo Lim, S.Y. Kang, Jung-Eun Park, Kyung Sik Kim, and C.K. Park
- Subjects
Radiation ,010308 nuclear & particles physics ,Iterative method ,Truncation ,Computer science ,business.industry ,Sharpening ,01 natural sciences ,Tomosynthesis ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Compressed sensing ,0103 physical sciences ,Medical imaging ,Computer vision ,Enhanced Data Rates for GSM Evolution ,Artificial intelligence ,business ,Nuclear medicine ,Image resolution - Abstract
Conventional digital tomosynthesis (DTS) based on the filtered-backprojection (FBP) reconstruction requires full field-of-view scan and also relatively dense projections, which results in still high dose for medical imaging purposes. In this work, to overcome these difficulties, we propose a new type of DTS examinations, the so-called scout-view assisted interior DTS (iDTS), in which the x-ray beam span covers only a small region-of-interest (ROI) containing target diagnosis with the help of some scout views and they are used in the reconstruction to add additional information to interior ROI otherwise absent with conventional iDTS reconstruction methods. We considered an effective iterative algorithm based on compressed-sensing theory, rather than the FBP-based algorithm, for more accurate iDTS reconstruction. We implemented the proposed algorithm, performed a systematic simulation and experiment, and investigated the image characteristics. We successfully reconstructed iDTS images of substantially high accuracy and no truncation artifacts by using the proposed method, preserving superior image homogeneity, edge sharpening, and in-plane spatial resolution.
- Published
- 2017
- Full Text
- View/download PDF
18. Effect of the Shape and Attached Position of Fabric Sensors on the Sensing Performance of Limb-motion Sensing Clothes
- Author
-
Dong-Jin Jeon, Hyunseung Cho, Joo Hyeon Lee, and Jin-Hee Yang
- Subjects
Environmental Engineering ,Position (vector) ,business.industry ,Computer science ,Motion sensing ,Computer vision ,Artificial intelligence ,business - Published
- 2017
- Full Text
- View/download PDF
19. Evaluation of high grid strip densities based on the moiré artifact analysis for quality assurance: Simulation and experiment
- Author
-
C.K. Park, Hyunwoo Lim, Kyung Sik Kim, Hyunseung Cho, Guna Kim, Duhee Jeon, Taeho Woo, Jung-Eun Park, Sang Young Park, Woo-Sik Kim, Uikyu Je, Do Yun Lee, Hunwoo Lee, and S.Y. Kang
- Subjects
Physics ,Nuclear and High Energy Physics ,business.industry ,Acoustics ,Detector ,STRIPS ,Grid ,01 natural sciences ,Sample (graphics) ,030218 nuclear medicine & medical imaging ,law.invention ,010309 optics ,03 medical and health sciences ,0302 clinical medicine ,law ,Nondestructive testing ,0103 physical sciences ,Nyquist rate ,business ,Instrumentation ,Quality assurance ,Image resolution - Abstract
We have recently developed precise x-ray grids having strip densities in the range of 100 – 250 lines/inch by adopting the precision sawing process and carbon interspace material for the demands of specific x-ray imaging techniques. However, quality assurance in the grid manufacturing has not yet satisfactorily conducted because grid strips of a high strip density are often invisible through an x-ray nondestructive testing with a flat-panel detector of an ordinary pixel resolution (>100 μ m). In this work, we propose a useful method to evaluate actual grid strip densities over the Nyquist sampling rate based on the moire artifact analysis. We performed a systematic simulation and experiment with several sample grids and a detector having a 143- μ m pixel resolution to verify the proposed quality assurance method. According to our results, the relative differences between the nominal and the evaluated grid strip densities were within 0.2% and 1.8% in the simulation and experiment, respectively, which demonstrates that the proposed method is viable with an ordinary detector having a moderate pixel resolution for quality assurance in grid manufacturing.
- Published
- 2017
- Full Text
- View/download PDF
20. Simulation of single grid-based phase-contrast x-ray imaging (g-PCXI)
- Author
-
C.K. Park, Guna Kim, Kyung Sik Kim, Uikyu Je, Hyunwoo Lim, W.H. Chung, Hunwoo Lee, J.W. Kim, Yeong-Tae Park, Sang Young Park, Sang Hoon Lee, Hyunseung Cho, J.G. Kim, Taeho Woo, and Do Yun Lee
- Subjects
Physics ,Nuclear and High Energy Physics ,Pixel ,Scattering ,business.industry ,Phase-contrast X-ray imaging ,media_common.quotation_subject ,Detector ,Grid ,01 natural sciences ,030218 nuclear medicine & medical imaging ,010309 optics ,03 medical and health sciences ,0302 clinical medicine ,Optics ,0103 physical sciences ,Contrast (vision) ,Focal Spot Size ,Absorption (electromagnetic radiation) ,business ,Instrumentation ,media_common - Abstract
Single grid-based phase-contrast x-ray imaging (g-PCXI) technique, which was recently proposed by Wen et al. to retrieve absorption, scattering, and phase-gradient images from the raw image of the examined object, seems a practical method for phase-contrast imaging with great simplicity and minimal requirements on the setup alignment. In this work, we developed a useful simulation platform for g-PCXI and performed a simulation to demonstrate its viability. We also established a table-top setup for g-PCXI which consists of a focused-linear grid (200-lines/in strip density), an x-ray tube (100-μm focal spot size), and a flat-panel detector (48-μm pixel size) and performed a preliminary experiment with some samples to show the performance of the simulation platform. We successfully obtained phase-contrast x-ray images of much enhanced contrast from both the simulation and experiment and the simulated contract seemed similar to the experimental contrast, which shows the performance of the developed simulation platform. We expect that the simulation platform will be useful for designing an optimal g-PCXI system.
- Published
- 2017
- Full Text
- View/download PDF
21. An Exploratory Study of Searching Human Body Segments for Motion Sensors of Smart Sportswear : Focusing on Rowing Motion
- Author
-
Bo-Ram Han, Joo Hyeon Lee, Hyunseung Cho, Jin-Sun Kim, Bokku Kang, Seonhyung Park, Han Sung Kim, and Hae Dong Lee
- Subjects
Environmental Engineering ,business.industry ,Computer science ,Rowing ,Exploratory research ,Computer vision ,Artificial intelligence ,business ,Motion (physics) ,Motion sensors - Published
- 2017
- Full Text
- View/download PDF
22. A Study on Product Development to Promote the Effects of Exercise on Children and to Induce Their Interest in Exercise : A Survey on the Development of Cognitive and Motor Functions in Children
- Author
-
Jung Chanwoong, Joo Hyeon Lee, Hyunseung Cho, and Yang Jin Hee
- Subjects
Environmental Engineering ,business.industry ,New product development ,Affective science ,Cognition ,Psychology ,business ,Developmental psychology - Published
- 2017
- Full Text
- View/download PDF
23. GCN-Based LSTM Autoencoder with Self-Attention for Bearing Fault Diagnosis
- Author
-
Daehee Lee, Hyunseung Choo, and Jongpil Jeong
- Subjects
bearing fault diagnosis ,fault simulator ,graph convolution network (GCN) ,self-attention ,long short-term memory (LSTM) autoencoder ,Chemical technology ,TP1-1185 - Abstract
The manufacturing industry has been operating within a constantly evolving technological environment, underscoring the importance of maintaining the efficiency and reliability of manufacturing processes. Motor-related failures, especially bearing defects, are common and serious issues in manufacturing processes. Bearings provide accurate and smooth movements and play essential roles in mechanical equipment with shafts. Given their importance, bearing failure diagnosis has been extensively studied. However, the imbalance in failure data and the complexity of time series data make diagnosis challenging. Conventional AI models (convolutional neural networks (CNNs), long short-term memory (LSTM), support vector machine (SVM), and extreme gradient boosting (XGBoost)) face limitations in diagnosing such failures. To address this problem, this paper proposes a bearing failure diagnosis model using a graph convolution network (GCN)-based LSTM autoencoder with self-attention. The model was trained on data extracted from the Case Western Reserve University (CWRU) dataset and a fault simulator testbed. The proposed model achieved 97.3% accuracy on the CWRU dataset and 99.9% accuracy on the fault simulator dataset.
- Published
- 2024
- Full Text
- View/download PDF
24. Application of a compressed-sensing (CS)-based deblurring scheme to digital tomosynthesis (DTS) for improved x-ray nondestructive testing: Simulation and experimental studies
- Author
-
Guna Kim, Yongjung Park, Kyung Sik Kim, Hyunseung Cho, Seung Min Park, Taeho Woo, Sang Young Park, Hyunwoo Lim, Uikyu Je, Cheol Keun Park, Changwoo Seo, and Hunwoo Lee
- Subjects
Scheme (programming language) ,Deblurring ,Computer science ,business.industry ,Mechanical Engineering ,Detector ,02 engineering and technology ,Atomic and Molecular Physics, and Optics ,Tomosynthesis ,030218 nuclear medicine & medical imaging ,Electronic, Optical and Magnetic Materials ,03 medical and health sciences ,0302 clinical medicine ,Compressed sensing ,Nondestructive testing ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Computer vision ,Artificial intelligence ,Electrical and Electronic Engineering ,Projection (set theory) ,business ,Image resolution ,computer ,computer.programming_language - Abstract
In this work, we investigated a compressed-sensing (CS)-based deblurring scheme for image deblurring of high accuracy in digital tomosynthesis (DTS). We implemented the proposed deblurring scheme and performed a systematic simulation to demonstrate its viability for improved x-ray nondestructive testing. We also performed an experiment by using a table-top setup which consists of an x-ray tube (90 kVp, 6 mAs) and a CMOS-type flat-panel detector having a 198-μm pixel resolution. In both the simulation and the experiment, 51 projection images were taken with a tomographic angle range of θ=60° and an angle step of Δθ=1.2° and then deblurred by using the proposed algorithm before performing the common filtered-backprojection (FBP)-based DTS reconstruction. Our results indicate that the proposed deblurring scheme appears to be effective for the blurring problems in DTS and is applicable to improve the image characteristics in the present x-ray nondestructive testing.
- Published
- 2016
- Full Text
- View/download PDF
25. Comparison of Biomechanical Characteristics of Rowing Performance between Elite and Non-Elite Scull Rowers: A Pilot Study
- Author
-
Bo Ram Han, Hyunseung Cho, Jin Sun Kim, Seonhyung Park, Joo Hyeon Lee, Han-Yeop Cho, Hae Dong Lee, and So Ya Yoon
- Subjects
musculoskeletal diseases ,medicine.medical_specialty ,business.industry ,Rowing ,Elbow ,030229 sport sciences ,Kinematics ,Knee Joint ,medicine.disease ,Sagittal plane ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,Physical medicine and rehabilitation ,Elite ,medicine ,business ,Range of motion ,Stroke ,030217 neurology & neurosurgery - Abstract
Objective: This study aimed to examine the characteristics of joint kinematics and synchronicity of rowing motion between elite and non-elite rowers. Methods: Two elite and two non-elite rowers performed rowing strokes (3 trials, 20 strokes in each trial) at three different stroke rates (20, 30, 40 stroke/min) on two stationary rowing ergometers. The rowing motions of the rowers were captured using a 3-dimensional motion analysis system (8-infrared camera VICON system, Oxford, UK). The range of motion (RoM) of the knee, hip, and elbow joints on the sagittal plane, the lead time (TLead) and the drive time TDrive) for each joint, and the elapsed time for the knee joint to maintain a fully extended position (TKnee) during the stroke were analyzed and compared between elite and non-elite rowers. Synchronicity of the rowing motion within and between groups was examined using coefficients of variation (CV) of the TDrive for each joint. Results: Regardless of the stroke rate, the RoM of all joints were greater for the elite than for non-elite rowers, except for the RoMs of the knee joint at 30 stroke/min and the elbow joint at 40 stroke/min (p < .05). Although the TLead at all stroke rates were the same between the groups, the TDrive for each joint was shorter for the elite than for the nonelite rowers. During the drive phase, elite rowers kept the fully extended knee joint angle longer than the non-elite rowers (p < .05). The CV values of the TDrive within each group were smaller for the elite compared with non-elite rowers, except for the CV values of the hip at all stroke/min and elbow at 40 stroke/min. Conclusion: The elite, compared with non-elite, rowers seem to be able to perform more powerful and efficient rowing strokes with large RoM and a short TDrive with the same TLead.
- Published
- 2016
- Full Text
- View/download PDF
26. Feasibility study for application of the compressed-sensing framework to interior computed tomography (ICT) for low-dose, high-accurate dental x-ray imaging
- Author
-
Sora Choi, Uikyu Je, C.K. Park, Guna Kim, Taeho Woo, Hyo-Min Cho, Yeong-Tae Park, Sang Young Park, Kyung Sik Kim, Hyunseung Cho, and Hyunwoo Lim
- Subjects
Radiation ,medicine.diagnostic_test ,business.industry ,Computer science ,Image quality ,Low dose ,X-ray ,020206 networking & telecommunications ,Computed tomography ,02 engineering and technology ,Imaging phantom ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Compressed sensing ,Position (vector) ,0202 electrical engineering, electronic engineering, information engineering ,medicine ,Computer vision ,Artificial intelligence ,Projection (set theory) ,Nuclear medicine ,business - Abstract
In this paper, we propose a new/next-generation type of CT examinations, the so-called Interior Computed Tomography (ICT), which may presumably lead to dose reduction to the patient outside the target region-of-interest (ROI), in dental x-ray imaging. Here an x-ray beam from each projection position covers only a relatively small ROI containing a target of diagnosis from the examined structure, leading to imaging benefits such as decreasing scatters and system cost as well as reducing imaging dose. We considered the compressed-sensing (CS) framework, rather than common filtered-backprojection (FBP)-based algorithms, for more accurate ICT reconstruction. We implemented a CS-based ICT algorithm and performed a systematic simulation to investigate the imaging characteristics. Simulation conditions of two ROI ratios of 0.28 and 0.14 between the target and the whole phantom sizes and four projection numbers of 360, 180, 90, and 45 were tested. We successfully reconstructed ICT images of substantially high image quality by using the CS framework even with few-view projection data, still preserving sharp edges in the images.
- Published
- 2016
- Full Text
- View/download PDF
27. 3D reconstruction based on compressed-sensing (CS)-based framework by using a dental panoramic detector
- Author
-
S.I. Cho, Hyo-Min Cho, Sang Young Park, Hyunseung Cho, Guna Kim, Uikyu Je, C.K. Park, Kyung Sik Kim, Hyunwoo Lim, Yeong-Tae Park, Dae-Ki Hong, and Taeho Woo
- Subjects
Engineering ,Dental panoramic ,Cost-Benefit Analysis ,Biophysics ,General Physics and Astronomy ,Iterative reconstruction ,Imaging phantom ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,Imaging, Three-Dimensional ,0302 clinical medicine ,Radiography, Dental ,Humans ,Computer Simulation ,Radiology, Nuclear Medicine and imaging ,Computer vision ,Mouth ,Phantoms, Imaging ,business.industry ,X-Rays ,Detector ,3D reconstruction ,Reproducibility of Results ,Reconstruction algorithm ,General Medicine ,Cone-Beam Computed Tomography ,Models, Theoretical ,Data Compression ,Compressed sensing ,030220 oncology & carcinogenesis ,Radiographic Image Interpretation, Computer-Assisted ,Artificial intelligence ,business ,Tooth ,Algorithms - Abstract
In this work, we propose a practical method that can combine the two functionalities of dental panoramic and cone-beam CT (CBCT) features in one by using a single panoramic detector. We implemented a CS-based reconstruction algorithm for the proposed method and performed a systematic simulation to demonstrate its viability for 3D dental X-ray imaging. We successfully reconstructed volumetric images of considerably high accuracy by using a panoramic detector having an active area of 198.4 mm × 6.4 mm and evaluated the reconstruction quality as a function of the pitch (p) and the angle step (Δθ). Our simulation results indicate that the CS-based reconstruction almost completely recovered the phantom structures, as in CBCT, for p≤2.0 and θ≤6°, indicating that it seems very promising for accurate image reconstruction even for large-pitch and few-view data. We expect the proposed method to be applicable to developing a cost-effective, volumetric dental X-ray imaging system.
- Published
- 2016
- Full Text
- View/download PDF
28. PCN90 Development of Time-Dependent Markov MODEL to Evaluate the Cost-Effectiveness of Treatment Options for Relapsed or Refractory Peripheral T-CELL Lymphoma in South Korea
- Author
-
S Park, Ah Young Kim, Hyung-Jin Kang, Hyunseung Cho, and Hyunna Lee
- Subjects
Oncology ,Refractory Peripheral T-cell Lymphoma ,medicine.medical_specialty ,Cost effectiveness ,business.industry ,Health Policy ,Internal medicine ,Economics, Econometrics and Finance (miscellaneous) ,medicine ,Treatment options ,Markov model ,business ,Pharmacology, Toxicology and Pharmaceutics (miscellaneous) - Published
- 2020
- Full Text
- View/download PDF
29. Sparse-view virtual monochromatic computed tomography reconstruction using a dictionary-learning-based algorithm
- Author
-
S.Y. Park, J.E. Park, Guna Kim, Y. Lim, Chang-Woo Seo, Kwang Soon Kim, Hyunseung Cho, Do Yun Lee, Woo-Sik Kim, H.W. Lee, Hyunwoo Lim, C.K. Park, Sangmook Kang, and Duhee Jeon
- Subjects
Physics ,Nuclear and High Energy Physics ,Basis (linear algebra) ,Digital Enhanced Cordless Telecommunications ,020206 networking & telecommunications ,02 engineering and technology ,Sparse approximation ,Imaging phantom ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,0202 electrical engineering, electronic engineering, information engineering ,Monochromatic color ,Linear combination ,Projection (set theory) ,Instrumentation ,Feature learning ,Algorithm - Abstract
Dual-energy computed tomography (DECT) is a well-known imaging technique that can be used to differentiate and classify material composition by using projection data acquired at two different x-ray tube voltages. Dual-energy projection data can be also used to create virtual monochromatic images as the potential to reduce beam-hardening artifacts that are usually observed in conventional polychromatic images. Despite DECT’s merits, main concerns in the use of DECT in clinics may be high radiation dose imposed to patients during the examinations. In this study, we investigated sparse-view virtual monochromatic CT reconstruction using a dictionary-learning (DL)-based algorithm to provide quantitative measurements at reduced radiation dose. DL is an advanced representation learning theory that aims to find a sparse representation of the input signal in the form of a linear combination of basis elements. To validate the proposed method, we performed a systematic simulation and also we made an experiment on a skull phantom using a commercially-available dental cone-beam CT system. Two data sets of 60 projections were acquired at 80 kV p and 120 kV p separately from the system and used to create virtual monochromatic images at 90 keV and 130 keV. The image qualities were evaluated in terms of the image intensity and the peak signal-to-noise ratio.
- Published
- 2020
- Full Text
- View/download PDF
30. Performance Evaluation of Fabric Sensors for Movement-monitoring Smart Clothing:Based on the Experiment on a Dummy
- Author
-
Hae Dong Lee, Joo Hyeon Lee, Seung-Jin Kang, Da-Hye Kang, Jung-Hoon Oh, Sun-Hyeong Park, Bo-Ram Han, Jeong-Whan Lee, Kang-Hwi Lee, and Hyunseung Cho
- Subjects
Engineering ,Environmental Engineering ,business.industry ,Human–computer interaction ,Movement (music) ,business ,Clothing ,Simulation - Published
- 2015
- Full Text
- View/download PDF
31. Experimental study on the application of a compressed-sensing (CS)-based deblurring method in x-ray nondestructive testing and its image performance
- Author
-
Seokwon Lee, Taeho Woo, Hyunwoo Lim, Kyung Sik Kim, Kir-Young Kim, Yongjung Park, Hyo-Min Cho, Uikyu Je, Cheol Keun Park, Sang Young Park, Dae-Ki Hong, Hyunseung Cho, and Sora Choi
- Subjects
Deblurring ,Noise power spectrum ,business.industry ,Computer science ,Mechanical Engineering ,Condensed Matter Physics ,Regularization (mathematics) ,Image (mathematics) ,Compressed sensing ,Modulation ,visual_art ,Nondestructive testing ,Electronic component ,visual_art.visual_art_medium ,General Materials Science ,Computer vision ,Artificial intelligence ,business - Abstract
We investigated the compressed-sensing (CS)-based deblurring framework incorporated with the total-variation (TV) regularization penalty for effective image deblurring of high accuracy in x-ray imaging. We implemented the proposed algorithm and performed a systematic experiment to demonstrate its viability for image deblurring in x-ray nondestructive testing. We obtained x-ray images of several selected electronic components at an x-ray tube condition of 80 kVp and 1.25 mAs and investigated the imaging characteristics in terms of the noise power spectrum and the modulation. We expect the proposed deblurring method to be applicable to improve the image characteristics considerably in x-ray nondestructive testing.
- Published
- 2015
- Full Text
- View/download PDF
32. Simulation and experimental studies of three-dimensional (3D) image reconstruction from insufficient sampling data based on compressed-sensing theory for potential applications to dental cone-beam CT
- Author
-
Dae-Ki Hong, C.K. Park, Hyunseung Cho, Yeong-Tae Park, Sora Choi, Myung-Shik Lee, Uikyu Je, Hyo-Min Cho, and Taeho Woo
- Subjects
Physics ,Nuclear and High Energy Physics ,medicine.medical_specialty ,Tomographic reconstruction ,medicine.diagnostic_test ,business.industry ,Sampling (statistics) ,Computed tomography ,Iterative reconstruction ,Compressed sensing ,3d image reconstruction ,medicine ,Medical physics ,Computer vision ,Artificial intelligence ,business ,Instrumentation ,Beam (structure) ,Dental cone - Abstract
In practical applications of three-dimensional (3D) tomographic imaging, there are often challenges for image reconstruction from insufficient sampling data. In computed tomography (CT), for example, image reconstruction from sparse views and/or limited-angle (
- Published
- 2015
- Full Text
- View/download PDF
33. Semi-Supervised Learning With Fact-Forcing for Medical Image Segmentation
- Author
-
Phuoc-Nguyen Bui, Duc-Tai Le, Junghyun Bum, Seongho Kim, Su Jeong Song, and Hyunseung Choo
- Subjects
Convolutional neural network ,fact-forcing process ,medical image segmentation ,semi-supervised learning ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Precise and robust image segmentation is one of the most important steps in supervised deep learning-applied studies. Especially in the medical field, image segmentation requires an enormous time and professionals with clinical knowledge. Although there are constant attempts for automatic and semi-automatic image segmentation algorithm development, acquiring not only clinically accurate but also precise pixel-level annotations for medical images remains insufficient. This article presents a semi-supervised learning method with a novel fact-forcing process, referred to as FFSS, to reduce the labeling cost while improving the prediction accuracy for medical image segmentation. FFSS includes two components: a pre-trained teacher and a student that would be trained, iteratively. In each iteration, the teacher first generates a pseudo-label for each image in an unlabeled set, the student is then trained on the pseudo-labeled set and sends feedback to update the teacher. A fact-forcing process is designed to improve the quality of the student model using a labeled set. We have comprehensively evaluated our method on both three-dimensional binary segmentation and two-dimensional multi-class segmentation. The evaluation results demonstrate significant accuracy improvements of FFSS compared with the state-of-the-art semi-supervised methods. Due to the fact-forcing process, the proposed method consistently outperforms the other ones under various labeled data ratios for all benchmark datasets, including left atrium MRI, pancreas CT, ACDC MRI, and OCT. By refining the quality of student feedback with complementary supervised training, the proposed FFSS shows robustness under labeled data scarcity for diverse types of medical images.
- Published
- 2023
- Full Text
- View/download PDF
34. Attention-Aided Generative Learning for Multi-Scale Multi-Modal Fundus Image Translation
- Author
-
Van-Nguyen Pham, Duc-Tai Le, Junghyun Bum, Eun Jung Lee, Jong Chul Han, and Hyunseung Choo
- Subjects
Conventional fundus images ,deep learning ,generative learning ,ophthalmology ,unpaired image-to-image translation ,ultra wide-field fundus images ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Conventional fundus images (CFIs) and ultra-widefield fundus images (UFIs) are two fundamental image modalities in ophthalmology. While CFIs provide a detailed view of the optic nerve head and the posterior pole of an eye, their clinical use is associated with high costs and patient inconvenience due to the requirement of good pupil dilation. On the other hand, UFIs capture peripheral lesions, but their image quality is sensitive to factors such as pupil size, eye position, and eyelashes, leading to greater variability between examinations compared to CFIs. The widefield retina view of UFIs offers the theoretical possibility of generating CFIs from available UFIs to reduce patient examination costs. A recent study has shown the feasibility of this approach by leveraging deep learning techniques for the UFI-to-CFI translation task. However, the technique suffers from the heterogeneous scales of the image modalities and variations in the brightness of the training data. In this paper, we address these issues with a novel framework consisting of three stages: cropping, enhancement, and translation. The first stage is an optic disc-centered cropping strategy that helps to alleviate the scale difference between the two image domains. The second stage mitigates the variation in training data brightness and unifies the mask between the two modalities. In the last stage, we introduce an attention-aided generative learning model to translate a given UFI into the CFI domain. Our experimental results demonstrate the success of the proposed method on 1,011 UFIs, with 99.8% of the generated CFIs evaluated as good quality and usable. Expert evaluations confirm significant visual quality improvements in the generated CFIs compared to the UFIs, ranging from 10% to 80% for features such as optic nerve structure, vascular distribution, and drusen. Furthermore, using generated CFIs in an AI-based diagnosis system for age-related macular degeneration results in superior accuracy compared to UFIs and competitive performance relative to real CFIs. These results showcase the potential of our approach for automatic disease diagnosis and monitoring.
- Published
- 2023
- Full Text
- View/download PDF
35. Image improvement in digital tomosynthesis (DTS) using a deep convolutional neural network
- Author
-
Chang-Woo Seo, Sung-Kwang Park, Gwangmook Kim, Y. Lim, Wonjin Kim, Kyung-Rae Kim, Hyunseung Cho, and D. Lee
- Subjects
Iterative and incremental development ,010308 nuclear & particles physics ,business.industry ,Computer science ,Image quality ,Deep learning ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Geometric tomography ,Iterative reconstruction ,01 natural sciences ,Convolutional neural network ,Tomosynthesis ,030218 nuclear medicine & medical imaging ,Image (mathematics) ,03 medical and health sciences ,0302 clinical medicine ,0103 physical sciences ,Computer vision ,Artificial intelligence ,business ,Instrumentation ,Mathematical Physics - Abstract
Digital tomosynthesis (DTS) is a geometric tomography technique using a limited-angle scan. It has been popularly used in both medical and industrial x-ray imaging applications. DTS provides the tomographic benefits of computed tomography with reduced dose and time. However, conventional DTS reconstruction based on the computationally cheap filtered back-projection (FBP) method typically produces poor image quality due to limited angular samplings. To overcome these difficulties, iterative reconstruction methods are often used in DTS reconstruction as they have the potential to provide multiplanar images of higher quality than conventional FBP-based methods. However, they require enormous computational cost in the iterative process, which remains an obstacle to practical applications. In this study, we propose a method for effectively reducing limited-angle artifacts in conventional FBP reconstruction, using a state-of-the-art deep learning scheme with a convolutional neural network. Our results indicate that the proposed DTS reconstruction method effectively minimized limited-angle artifacts, thus improving image performance in DTS, and that further it provided good image quality in both sagittal and coronal views (as in computed tomography) as well as in axial view.
- Published
- 2019
- Full Text
- View/download PDF
36. PCN437 RECONSTRUCTION OF INDIVIDUAL PATIENT DATA FROM PUBLISHED SURVIVAL CURVES: CASE OF PRALATREXATE FOR PERIPHERAL T-CELL LYMPHOMAS
- Author
-
Hyunseung Cho, Hye Young Kang, S.J. Heo, and A. Kim
- Subjects
Oncology ,medicine.medical_specialty ,business.industry ,Health Policy ,T cell ,Public Health, Environmental and Occupational Health ,Pralatrexate ,Patient data ,Peripheral ,medicine.anatomical_structure ,Internal medicine ,medicine ,business ,Survival analysis ,medicine.drug - Published
- 2019
- Full Text
- View/download PDF
37. A projection-based sparse-view virtual monochromatic computed tomography method based on a compressed-sensing algorithm
- Author
-
Gwangmook Kim, Eungman Lee, Hyunseung Cho, Sun-Ae Park, Duhee Jeon, Chang-Woo Seo, C.K. Park, Seokyoon Kang, Kyung-Rae Kim, Hyunna Lee, D. Lee, Y. Lim, Wonjin Kim, H.Y. Lim, and Jung Su Park
- Subjects
Basis (linear algebra) ,010308 nuclear & particles physics ,Computer science ,Attenuation ,01 natural sciences ,030218 nuclear medicine & medical imaging ,Reduction (complexity) ,03 medical and health sciences ,0302 clinical medicine ,Compressed sensing ,0103 physical sciences ,Nyquist–Shannon sampling theorem ,Monochromatic color ,Projection (set theory) ,Instrumentation ,Algorithm ,Mathematical Physics ,Energy (signal processing) - Abstract
Computed tomography (CT) images obtained at different monochromatic X-ray beam energies can be synthesized from conventional dual-energy CT scans. This approach to synthesizing monochromatic CT images is based on basis material decomposition and the knowledge of attenuation of basis materials. The main benefits of virtual monochromatic CT (VMCT) images include reduction of beam-hardening artifacts and provision of accurate atteuation measurements. Despite the VMCT's benefits, main concerns in the use of VMCT in clinics may be high radiation dose the patient is exposed to. In this study, we investigated a projection-based sparse-view VMCT method in an attempt to overcome these difficulties. We performed a computational simulation and evaluated the feasibility of using the VMCT method in sparse-view CT. Two polychromatic data sets of 90 projections, far less than what is required by the Nyquist sampling theory, were simulated at 80 kVp and 140 kVp and used to synthesize VMCT images at a monochromatic energy range of 40–140 keV . VMCT image characteristics were quantitatively evaluated in terms of intensity profile, the contrast-to-noise ratio, and the signal-to-noise ratio. Our results indicate that the CS-based algorithm produced high-quality sparse-view CT images, and thereby the proposed VMCT method yielded CT image results of improved beam-hardening artifacts and quantitative measurements.
- Published
- 2019
- Full Text
- View/download PDF
38. Analytic digital tomosynthesis reconstruction in partial sampling with a multislit collimator using a prior sinogram interpolation method
- Author
-
Seokyoon Kang, Chang-Woo Seo, C.K. Park, D. Lee, Sung-Kwang Park, Kyung-Rae Kim, Duhee Jeon, Hyunna Lee, Hyunseung Cho, Gwangmook Kim, Y. Lim, H.Y. Lim, Wonjin Kim, and Jung Su Park
- Subjects
Pixel ,Image quality ,business.industry ,Computer science ,Collimator ,Tomosynthesis ,law.invention ,Data acquisition ,Sampling (signal processing) ,law ,Computer vision ,Artificial intelligence ,Projection (set theory) ,business ,Instrumentation ,Mathematical Physics ,Interpolation - Abstract
This study investigated analytic digital tomosynthesis (DTS) reconstruction in partial sampling with a multislit collimator that partially blocks the x-ray beam to the patient during projection data acquisition, thereby reducing excessive radiation dose to patients. Partially-sampled DTS images reconstructed using the analytic filtered-backprojection (FBP) algorithm usually suffer from severe bright-band artifacts around multislit edges of the collimator due to incomplete spatial sampling. In this study, a new prior sinogram interpolation method was introduced to the analytic DTS reconstruction in partial sampling to alleviate such artifacts. To verify the proposed DTS method, we conducted a systematic simulation and investigated image characteristics. Three multislit collimator layouts of C(2/2), C(3/3), and C(4/4) with a 50% duty cycle were designed and used in the simulation. Here C(n/n) denotes a collimator layout that blocks the x-ray beam over n detector pixels vertically with a n-pixel interval. All projections were obtained at a tomographic angle of θ = ±40o and an angle step of Δθ = 2o and used to reconstruct DTS images using the FBP algorithm. Our results indicate that the proposed sinogram interpolation method effectively minimized bright-band artifacts in analytic DTS reconstruction in partial sampling, thus maintaining the image quality.
- Published
- 2019
- Full Text
- View/download PDF
39. Compressed-sensing (CS)-based 3D image reconstruction in cone-beam CT (CBCT) for low-dose, high-quality dental X-ray imaging
- Author
-
Sora Choi, Myung-Shik Lee, Uikyu Je, Hyo-Min Cho, Yeong-Tae Park, Yangseo Koo, Seungduk Lee, Hyunseung Cho, Dae-Ki Hong, Jooyoung Oh, and H.J. Kim
- Subjects
medicine.medical_specialty ,business.industry ,Image quality ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,General Physics and Astronomy ,Reconstruction algorithm ,Image processing ,Compressed sensing ,Sampling (signal processing) ,medicine ,Nyquist–Shannon sampling theorem ,Medical physics ,Computer vision ,Ligand cone angle ,Tomography ,Artificial intelligence ,business - Abstract
The most popular reconstruction algorithm for cone-beam computed tomography (CBCT) is based on the computationally-inexpensive filtered-backprojection (FBP) method. However, that method usually requires dense projections over the Nyquist samplings, which imposes severe restrictions on the imaging doses. Moreover, the algorithm tends to produce cone-beam artifacts as the cone angle is increased. Several variants of the FBP-based algorithm have been developed to overcome these difficulties, but problems with the cone-beam reconstruction still remain. In this study, we considered a compressed-sensing (CS)-based reconstruction algorithm for low-dose, high-quality dental CBCT images that exploited the sparsity of images with substantially high accuracy. We implemented the algorithm and performed systematic simulation works to investigate the imaging characteristics. CBCT images of high quality were successfully reconstructed by using the built-in CS-based algorithm, and the image qualities were evaluated quantitatively in terms of the universal-quality index (UQI) and the slice-profile quality index (SPQI).We expect the reconstruction algorithm developed in the work to be applicable to current dental CBCT systems, to reduce imaging doses, and to improve the image quality further.
- Published
- 2013
- Full Text
- View/download PDF
40. Retinal Disease Diagnosis Using Deep Learning on Ultra-Wide-Field Fundus Images
- Author
-
Toan Duc Nguyen, Duc-Tai Le, Junghyun Bum, Seongho Kim, Su Jeong Song, and Hyunseung Choo
- Subjects
medical image processing ,deep learning ,fundus image ,convolutional neural network ,vision transformer ,Medicine (General) ,R5-920 - Abstract
Ultra-wide-field fundus imaging (UFI) provides comprehensive visualization of crucial eye components, including the optic disk, fovea, and macula. This in-depth view facilitates doctors in accurately diagnosing diseases and recommending suitable treatments. This study investigated the application of various deep learning models for detecting eye diseases using UFI. We developed an automated system that processes and enhances a dataset of 4697 images. Our approach involves brightness and contrast enhancement, followed by applying feature extraction, data augmentation and image classification, integrated with convolutional neural networks. These networks utilize layer-wise feature extraction and transfer learning from pre-trained models to accurately represent and analyze medical images. Among the five evaluated models, including ResNet152, Vision Transformer, InceptionResNetV2, RegNet and ConVNext, ResNet152 is the most effective, achieving a testing area under the curve (AUC) score of 96.47% (with a 95% confidence interval (CI) of 0.931–0.974). Additionally, the paper presents visualizations of the model’s predictions, including confidence scores and heatmaps that highlight the model’s focal points—particularly where lesions due to damage are evident. By streamlining the diagnosis process and providing intricate prediction details without human intervention, our system serves as a pivotal tool for ophthalmologists. This research underscores the compatibility and potential of utilizing ultra-wide-field images in conjunction with deep learning.
- Published
- 2024
- Full Text
- View/download PDF
41. Sparse-view image reconstruction in inverse-geometry CT (IGCT) for fast, low-dose, volumetric dental X-ray imaging
- Author
-
Seungduk Lee, Hyunseung Cho, Hyo-Min Cho, Dae-Ki Hong, Yangseo Koo, Yongjung Park, S. I. Choi, Jooyoung Oh, H.J. Kim, Uikyu Je, and Myung-Shik Lee
- Subjects
Integrated gate-commutated thyristor ,Computer science ,Temporal resolution ,Detector ,X-ray ,General Physics and Astronomy ,Inverse ,Reconstruction algorithm ,Geometry ,Iterative reconstruction ,Collimated light - Abstract
As a new direction for computed tomography (CT) imaging, inverse-geometry CT (IGCT) has been recently introduced and is intended to overcome limitations in conventional cone-beam CT (CBCT) such as the cone-beam artifacts, imaging dose, temporal resolution, scatter, cost, and so on. While the CBCT geometry consists of X-rays emanating from a small focal spot and collimated toward a larger detector, the IGCT geometry employs a large-area scanned source array with the Xray beams collimated toward a smaller-area detector. In this research, we explored an effective IGCT reconstruction algorithm based on the total-variation (TV) minimization method and studied the feasibility of the IGCT geometry for potential applications to fast, low-dose volumetric dental X-ray imaging. We implemented the algorithm, performed systematic simulation works, and evaluated the imaging characteristics quantitatively. Although much engineering and validation works are required to achieve clinical implementation, our preliminary results have demonstrated a potential for improved volumetric imaging with reduced dose.
- Published
- 2012
- Full Text
- View/download PDF
42. Compressed-sensing (CS)-based micro-DTS reconstruction for applications of fast, low-dose x-ray imaging
- Author
-
Hyunseung Cho, Jooyoung Oh, H.J. Kim, Dae-Ki Hong, Yeong-Tae Park, Sora Choi, Hyo-Min Cho, Yangseo Koo, Seungduk Lee, Uikyu Je, and Myung-Shik Lee
- Subjects
medicine.medical_specialty ,Mean squared error ,business.industry ,Computer science ,General Physics and Astronomy ,Reconstruction algorithm ,Iterative reconstruction ,Tomosynthesis ,Compressed sensing ,medicine ,Figure of merit ,Medical physics ,Computer vision ,Artificial intelligence ,Tomography ,business ,Beam (structure) - Abstract
In this paper, we introduce limited-angle tomography in which the object being imaged is rotated around the center of an inclined X-ray beam, the so-called micro-DTS (digital tomosynthesis), with a few-view image reconstruction based on the compressed-sensing (CS) theory for applications of fast, low-dose X-ray imaging. We implemented an effective CS-based reconstruction algorithm for micro-DTS and performed systematic simulation works. The assessment of the image characteristics was performed by using several figures of merit such as the root-mean-square error (RMSE), the contrast-to-noise ratio (CNR), and the universal image-quality index (UQI) to compare the reconstructed images to the simulated phantoms. According to our results, compared to the FBP-based method, the CS-based reconstruction method substantially enhanced image accuracy against image artifacts from few-view and limited-angle projections. In the simulation, 41 projections were used for the half-tomographic angles of 30°, 45°, and 60°, giving UQI values of 0.92 ∼ 0.97, which seems promising for potential applications of fast, low-dose X-ray imaging.
- Published
- 2012
- Full Text
- View/download PDF
43. Application of digital tomosynthesis (DTS) of optimal deblurring filters for dental X-ray imaging
- Author
-
Sora Choi, Uikyu Je, Hyunseung Cho, Jooyoung Oh, and Du Su Kim
- Subjects
Dental radiography ,Deblurring ,medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,Computer science ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,General Physics and Astronomy ,Reconstruction algorithm ,Image processing ,Tomosynthesis ,Signal-to-noise ratio ,medicine ,Computer vision ,Medical physics ,Artificial intelligence ,Noise (video) ,Tomography ,business - Abstract
Digital tomosynthesis (DTS) is a limited-angle tomographic technique that provides some of the tomographic benefits of computed tomography (CT) but at reduced dose and cost. Thus, the potential for application of DTS to dental X-ray imaging seems promising. As a continuation of our dental radiography R&D, we developed an effective DTS reconstruction algorithm and implemented it in conjunction with a commercial dental CT system for potential use in dental implant placement. The reconstruction algorithm employed a backprojection filtering (BPF) method based upon optimal deblurring filters to suppress effectively both the blur artifacts originating from the out-focus planes and the high-frequency noise. To verify the usefulness of the reconstruction algorithm, we performed systematic simulation works and evaluated the image characteristics. We also performed experimental works in which DTS images of enhanced anatomical resolution were successfully obtained by using the algorithm and were promising to our ongoing applications to dental X-ray imaging. In this paper, our approach to the development of the DTS reconstruction algorithm and the results are described in detail.
- Published
- 2012
- Full Text
- View/download PDF
44. Adaptive panoramic tomography with a circular rotational movement for the formation of multifocal image layers
- Author
-
Yangseo Koo, Sora Choi, Yeong-Tae Park, Uikyu Je, Hyunseung Cho, Dae-Ki Hong, and Du Su Kim
- Subjects
Movement (music) ,Image quality ,Computer science ,business.industry ,Radiography ,General Physics and Astronomy ,Reconstruction algorithm ,Image (mathematics) ,Optics ,Computer vision ,Artificial intelligence ,Imaging technique ,Tomography ,business ,Focus (optics) - Abstract
Panoramic radiography with which only structures within a certain image layer are in focus and others out of focus on the panoramic image has become a popular imaging technique especially in dentistry. However, the major drawback to the technique is a mismatch between the structures to be focused and the predefined image layer mainly due to the various shapes and sizes of dental arches and/or to malpositioning of the patient. These result in image quality typically inferior to that obtained using intraoral radiographic techniques. In this paper, to overcome these difficulties, we suggest a new panoramic reconstruction algorithm, the so-called adaptive panoramic tomography (APT), capable of reconstructing multifocal image layers with no additional exposure. In order to verify the effectiveness of the proposed algorithm, we performed systematic simulation studies with a circular rotational movement and investigated the image performance.
- Published
- 2012
- Full Text
- View/download PDF
45. Measurement profiles of nano-scale ion beam for optimized radiation energy losses
- Author
-
Hyunseung Cho and T.H. Woo
- Subjects
Physics ,Nuclear and High Energy Physics ,Range (particle radiation) ,Ion beam ,Quantitative Biology::Tissues and Organs ,Physics::Medical Physics ,Radiant energy ,Bragg peak ,Charged particle ,Computational physics ,Ion ,law.invention ,law ,Ionization ,Atomic physics ,Collider ,Instrumentation - Abstract
The behavior of charged particles is investigated for nano-scale ion beam therapy using a medical accelerator. Computational work is performed for the Bragg-peak simulation, which is focused on human organ material of pancreas and thyroid. The Results show that the trends of the dose have several different kinds of distributions. Before constructing a heavy ion collider, this study can give us the reliability of the therapeutic effect. Realistic treatment using human organs is calculated in a simple and cost effective manner using the computational code, the Stopping and Range of Ions in Matter 2008 (SRIM 2008). Considering the safety of the therapy, it is suggested to give a patient orient planning of the cancer therapy. The energy losses in ionization and phonon are analyzed, which are the behaviors in the molecular level nano-scopic investigation. The different fluctuations are shown at 150 MeV, where the lowest temperature is found in proton and pancreas case. Finally, the protocol for the radiation therapy is constructed by the simulation in which the procedure for a better therapy is selected. An experimental measurement incorporated with the simulations could be programmed by this protocol.
- Published
- 2011
- Full Text
- View/download PDF
46. Nano-scopic measurement for radiation of nuclear waste forms using ion beam injection in the drum treatment
- Author
-
Hyunseung Cho and T.H. Woo
- Subjects
Nuclear physics ,Physics ,Nuclear and High Energy Physics ,Range (particle radiation) ,Radiation material science ,Ion beam ,Nuclear engineering ,Atom ,Radioactive waste ,Alpha particle ,Radiation ,Instrumentation ,Ion - Abstract
The irradiation-induced nuclear waste material has been investigated. Alpha particles are considered as the waste radiation. The material aspects are considered for four kinds of materials, which are used for the nuclear waste forms. These materials are compared for the possibility of the irradiation-induced amorphization. Several variables are investigated for the ion radiation interactions. We have used the Stopping and Range of Ion in Matter 2008 (SRIM 2008) code system to show that the ion dose is changed to the displacement per atom (dpa) completely and the kinetic energy is transferred to each target atom through nuclear collision. The necessary thickness of the waste form has been investigated. More reasonable study has been done for the nuclear waste material container. The thickness of 204 nm is considered for the optimized structure of waste drum by crystalline silicotitanate.
- Published
- 2011
- Full Text
- View/download PDF
47. Fabrication and optimization of a fiber-optic radiation sensor for proton beam dosimetry
- Author
-
Jang-Yeon Park, Dong Ho Shin, Jeong Ki Seo, Sam-Yong Park, Ji Yeon Heo, Bongsoo Lee, Hyunseung Cho, Wook Jae Yoo, Jinsoo Moon, Kyoung-Won Jang, and E.J. Hwang
- Subjects
Physics ,Nuclear and High Energy Physics ,Scintillation ,Dosimeter ,Proton ,Physics::Instrumentation and Detectors ,business.industry ,Physics::Medical Physics ,Stopping power ,Scintillator ,Optics ,Physics::Accelerator Physics ,Dosimetry ,business ,Instrumentation ,Proton therapy ,Beam (structure) - Abstract
In this study, we fabricated a fiber-optic radiation sensor for proton therapy dosimetry and measured the output and the peak-to-plateau ratio of scintillation light with various kinds of organic scintillators in order to select an organic scintillator appropriate for measuring the dose of a proton beam. For the optimization of an organic scintillator, the linearity between the light output and the stopping power of a proton beam was evaluated for two different diameters of the scintillator, and the angular dependency and standard deviation of the light pulses were investigated for four different scintillator lengths. We also evaluated the linearity between the light output and the dose rate and monitor units of a proton generator, respectively. The relative depth–dose curve of the proton beam was obtained and corrected using Birk’s theory.
- Published
- 2011
- Full Text
- View/download PDF
48. PIN74 - A SYSTEMATIC REVIEW ON ECONOMIC EVALUATION OF ROTAVIRUS VACCINATION
- Author
-
Hyun-Suk Kang, Hyunseung Cho, Hyunna Lee, and Myung-Hyun Lee
- Subjects
business.industry ,Health Policy ,Environmental health ,Economic evaluation ,Public Health, Environmental and Occupational Health ,Medicine ,Rotavirus vaccination ,business - Published
- 2018
- Full Text
- View/download PDF
49. Estimating The Incremental Resource Utilization And Economic Cost Attributable To Heart Failure In South Korea
- Author
-
Hyun-Suk Kang, Hyunseung Cho, Sung-Soo Oh, and Hyunna Lee
- Subjects
Natural resource economics ,Health Policy ,Heart failure ,Economic cost ,Public Health, Environmental and Occupational Health ,medicine ,Business ,medicine.disease ,Resource utilization - Published
- 2018
- Full Text
- View/download PDF
50. The Introduction of Rotavirus Vaccine in the Korean Market: Epidemiologic and Economic Consequences
- Author
-
Hyunna Lee, Hyun-Suk Kang, and Hyunseung Cho
- Subjects
Geography ,Health Policy ,Environmental health ,Public Health, Environmental and Occupational Health ,Rotavirus vaccine ,Economic consequences - Published
- 2018
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.