• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.3
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• pp.119-126
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• 2005

Electrical resistance tomography(ERT) maps resistivity values of the soil subsurface and characterizes buried objects. The characterization includes location, size and resistivity of buried objects. In this paper, Gauss-Newton, truncated least squares(TLS) and simultaneous iterative reconstruction technique(SIRT) methods are presented for the solution of the ERT image reconstruction. Computer simulations show that the spatial resolution of the reconstructed images by the TLS approach is improved as compared to those obtained by the Gauss-Newton and SIRT method.

• Fashion & Textile Research Journal
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• v.12 no.6
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• pp.812-820
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• 2010

The objectives of this study were to classify the head shapes of Korean men and to suggest computer tomography as a new body measurement method. The 23 head measurement items of 760 men, aged more than 18 in Sizekorea 2004 database were used to analyze, measured by using statistical methods. Factor analysis, cluster analysis and duncan test were performed using these data. Through factor analysis, 5 factors were extracted upon factor scores and those factors comprised 70.91% for the total variances. The head and face shapes were categorized as 5 types-triangle, round, oval, long, rectangle. We decided for the type 1(triangle) to standard head shape since this type was the most observed. 21 participants were measured using computed tomography(CT). The measured data of skin and skeleton and the standard head shapes were illustrated.

• Journal of Sensor Science and Technology
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• v.21 no.3
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• pp.217-222
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• 2012

Optical coherence tomography(OCT) is a noninvasive optical imaging tool for biomedical applications. OCT can provide depth resolved two/three dimensional morphological images on biological samples. In this paper, we integrated an OCT system that was composed of an SLED(Superluminescent Light Emitting Diode, ${\lambda}_0$=1305 nm bandwith= 141 nm), a reference arm adopting a rapid scanning optical delay line(RSOD) to get high speed imaging, and a sample arm that used a micro electro mechanical systems(MEMS) scanning mirror. The sample arm contained a compact probe for imaging dental structures. The performance of the system was evaluated by imaging in-vivo human teeth with dental calculus, and the results indicated distinct appearance of dental calculus from enamel, gum or decayed teeth. The developed probe and system could successfully confirm the presence of dental calculus with a very high spatial resolution($6{\mu}m$).

• Journal of the Optical Society of Korea
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• v.16 no.2
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• pp.133-140
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• 2012

In this study we investigate the use of 2D and 3D scanning optical coherence tomography (OCT) technology for use in apple blotch diagnosis. In order to test the possible application of OCT as a detection tool for apple trees affected by Marssonina coronaria, we conducted several experiments and compared the results from both healthy and infected leaves. Using OCT, we found several distinctive features in the subsurface boundary regions of both the diseased and healthy leaves. Our results indicate that leaves from diseased trees, while still appearing healthy, can be affected by M. coronaria. The A-scan analysis method confirmed that the boundaries found under the subsurface layers can be faint. This shows that M. coronaria can exert its influence on entire apple trees (as opposed to only on leaves with lesions) once it infects healthy trees. Our results indicate that OCT can be used as a noninvasive tool for the diagnosis of fungal disease in apple trees. Microscopic imaging results, performed as a histological study for comparison, correlated well with the OCT results.

• The Journal of Engineering Research
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• v.2 no.1
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• pp.49-56
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• 1997

In emission computed tomography, statistical reconstruction methods in the context of a Bayesian framework have been a topic of interest over the last decade. This was mainly due to the fact that Bayesian approaches can incorporate a priori information into the reconstruction algorithm. Although these approaches can exhibit good performance, their applications to the clinic is hindered mainly by their high computational cost. On the other hand, the speed and simplicity of the filtered backprojection (FBP) algorithm have led to its widespread use in most clinical applications. In this work, we use spline models, which have been quite useful in Bayesian reconstruction, as regularizers for high-frequency apodization in FBP algorithm and show that the effects of using spline models as priors in Bayesian reconstruction can also be achieved in FBP reconstruction.

• Journal of the Korea Society of Computer and Information
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• v.24 no.3
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• pp.41-47
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• 2019

In this paper, we propose a application of conditional generative adversarial network (cGAN) for generation of contrast enhanced computed tomography (CT) image. Two types of CT data which were the enhanced and non-enhanced were used and applied by the histogram equalization for adjusting image intensities. In order to validate the generation of contrast enhanced CT data, the structural similarity index measurement (SSIM) was performed. Prepared generated contrast CT data were analyzed the statistical analysis using paired sample t-test. In order to apply the optimized algorithm for the lymph node cancer, they were calculated by short to long axis ratio (S/L) method. In the case of the model trained with CT data and their histogram equalized SSIM were $0.905{\pm}0.048$ and $0.908{\pm}0.047$. The tumor S/L of generated contrast enhanced CT data were validated similar to the ground truth when they were compared to scanned contrast enhanced CT data. It is expected that advantages of Generated contrast enhanced CT data based on deep learning are a cost-effective and less radiation exposure as well as further anatomical information with non-enhanced CT data.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.85-88
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• 1998

We have developed an eigenvalue method for impedance computed tomography to improve the ill-conditioning problem. We have compared the performance of this method and the balancing method by computer simulations. As a result, it was proved that this method is better than the balancing method very much. It was found that the initial value condition is not so severe to obtain good images.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.1
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• pp.167-172
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• 1987

In this paper, the interpolation schemes for Direct Fourier Reconstruction in Diffraction Tomography are discussed. The interpolator using circular sampling theorem is modified so that the reconstructed image may be closer to original object than those produced with other interpolators. Reconstructed images obtained by computer simulations with several interpolators including that derived in this paper are compared to original object: two concentric cylinders.

• Korean Journal of Mathematics
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• v.4 no.1
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• pp.7-16
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• 1996

The optimization problems with quadratic constraints often appear in various fields such as network flows and computer tomography. In this paper, we propose an algorithm for solving those problems and prove the convergence of the proposed algorithm.

• Journal of Biomedical Engineering Research
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• v.34 no.3
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• pp.135-140
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• 2013

We have developed an ultra wide-field of view Optical Coherence Tomography(OCT) which has capability to 2D and 3D views of cross-sectional structure of in vivo human retina. Conventional OCT has a limitation in visualizing the entire retina due to a reduced field of view. We designed an optical setup to significantly improve the lateral scanning range to be more than 20 mm. The entire human retinal structure in 2D and 3D was reported in this paper with the developed OCT system. Also, we empirically searched an optimized image size for real time visualization by analyzing variation of the frame rate with different lateral scan points. The size was concluded to be $1024{\times}2000{\times}300$ pixels which took 9 seconds for visualization.