• Current Optics and Photonics
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• v.3 no.1
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• pp.8-15
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• 2019

We describe a common optical system that merges a LADAR system, which generates a point cloud, and a more traditional imaging system operating in the LWIR, which generates image data. The optimum diameter of the entrance pupil was determined by analysis of detection ranges of the LADAR sensor, and the result was applied to design a common optical system using LADAR sensors and LWIR sensors; the performance of these sensors was then evaluated. The minimum detectable signal of the $128{\times}128-pixel$ LADAR detector was calculated as 20.5 nW. The detection range of the LADAR optical system was calculated to be 1,000 m, and according to the results, the optimum diameter of the entrance pupil was determined to be 15.7 cm. The modulation transfer function (MTF) in relation to the diffraction limit of the designed common optical system was analyzed and, according to the results, the MTF of the LADAR optical system was 98.8% at the spatial frequency of 5 cycles per millimeter, while that of the LWIR optical system was 92.4% at the spatial frequency of 29 cycles per millimeter. The detection, recognition, and identification distances of the LWIR optical system were determined to be 5.12, 2.82, and 1.96 km, respectively.

• Progress in Medical Physics
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• v.31 no.3
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• pp.81-98
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• 2020

This review aims to provide a brief, comprehensive overview of advanced technologies of nuclear medicine physics, with a focus on recent developments from both hardware and software perspectives. Developments in image acquisition/reconstruction, especially the time-of-flight and point spread function, have potential advantages in the image signal-to-noise ratio and spatial resolution. Modern detector materials and devices (including lutetium oxyorthosilicate, cadmium zinc tellurium, and silicon photomultiplier) as well as modern nuclear medicine imaging systems (including positron emission tomography [PET]/computerized tomography [CT], whole-body PET, PET/magnetic resonance [MR], and digital PET) enable not only high-quality digital image acquisition, but also subsequent image processing, including image reconstruction and post-reconstruction methods. Moreover, theranostics in nuclear medicine extend the usefulness of nuclear medicine physics far more than quantitative image-based diagnosis, playing a key role in personalized/precision medicine by raising the importance of internal radiation dosimetry in nuclear medicine. Now that deep-learning-based image processing can be incorporated in nuclear medicine image acquisition/processing, the aforementioned fields of nuclear medicine physics face the new era of Industry 4.0. Ongoing technological developments in nuclear medicine physics are leading to enhanced image quality and decreased radiation exposure as well as quantitative and personalized healthcare.

• Journal of the Korea Society of Computer and Information
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• v.24 no.12
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• pp.51-57
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• 2019

In this paper, we analyzed the performance of IoT based smart wearable mine detection device. There are various mine detection methods currently used by the military. Still, in the general field, mine detection is performed by visual detection, probe detection, detector detection, and other detection methods. The detection method by the detector is using a GPR sensor on the detector, which is possible to detect metals, but it is difficult to identify non-metals. It is hard to distinguish whether the area where the detection was performed or not. Also, there is a problem that a lot of human resources and time are wasted, and if the user does not move the sensor at a constant speed or moves too fast, it is difficult to detect landmines accurately. Therefore, we studied the smart wearable mine detection device composed of human body antenna, main microprocessor, smart glasses, body-mounted LCD monitor, wireless data transmission, belt type power supply, black box camera, which is to improve the problem of the error of mine detection using unidirectional ultrasonic sensing signal. Based on the results of this study, we will conduct an experiment to confirm the possibility of detecting underground mines based on the Internet of Things (IoT). This paper consists of an introduction, experimental environment composition, simulation analysis, and conclusion. Introduction introduces the research contents such as mines, mine detectors, and research progress. It consists of large anti-personnel mine, M16A1 fragmented anti-mine, M15 and M19 antitank mines, plastic bottles similar to mines and aluminum cans. Simulation analysis is conducted by using MATLAB to analyze the mine detection device implementation performance, generating and transmitting IoT signals, and analyzing each received signal to verify the detection performance of landmines. Then we will measure the performance through the simulation of IoT-based mine detection algorithm so that we will prove the possibility of IoT-based detection landmine.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.4
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• pp.94-101
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• 2009

In this paper, we propose design of hardware based on a high speed digital signal processor (DSP) and a field programmable gate array (FPGA) for real-time suppression of fixed pattern noise (FPN) using hardware neural networks (HNN) in cooled infrared focal plane array (IRFPA) imaging system FPN appears a limited operation by temperature in observable images which applies to non-uniformity correction for infrared detector. These have very important problems because it happen serious problem for other applications as well as degradation for image quality in our system Signal processing architecture for our system operates reference gain and offset values using three tables for low, normal, and high temperatures. Proposed method creates virtual tables to separate for overlapping region in three offset tables. We also choose an optimum tenn of temperature which controls weighted values of HNN using mean values of pixels in three regions. This operates gain and offset tables for low, normal, and high temperatures from mean values of pixels and it recursively don't have to do an offset compensation in operation of our system Based on experimental results, proposed method showed improved quality of image which suppressed FPN by change of temperature distribution from an observational image in real-time system.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.12
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• pp.59-65
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• 2004

A stable reference voltage generator is necessary to the infrared image signal readout circuit(ROIC) to improve noise characteristics of signal originated from infrared devices, that is, to gain good images. In this paper, bandgap circuit operating at cryogenic temperature of 77K for Infrared image ROIC(readout integrated circuit) was first made. It demonstrates practical use possibility through taking measurements and estimations. Bandgap circuit is a representative voltage reference circuit. Most of bandgap reference circuits which are presented so far operate at room temperature, and their characteristic are not suitable for infrared image ROIC operating at liquid nitrogen temperature, 77K. To design bandgap circuit operating at cryogenic temperature, suitable circuit is selected and the parameter characteristics of used devices as temperature change are seen by a theoretical study and fitted at liquid temperature with considering such characteristics. This circuit has been fabricated in the Hynix 0.6um standard CMOS process, and the output voltage measured shows that the stability is 1.042±0.0015V over the temperature range of 60K to 110K and is better than bandgap circuits operated at room temperature.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.277-284
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• 2013

The analysis of phase synchronization characteristics from EEG signals is important for the understanding of information processing functionality in the brain network. In this paper, wavelet transformation(WT), Hilbert tansformation (HT), complex demodulation (CD) methods having time localization characteristics were applied to real evoked potential data and noise added simulation data with center frequencies corresponding to EEG bands for the estimation performance analysis of phase offset, phase changing point, and interband crosstalk. The WT is the best both in ${\delta}$, ${\theta}$, and ${\alpha}$ band signal decomposition, and in analyzing phase synchronization performance. The CD can be efficiently used in changing point detection under tolerant noise condition because of its abrupt performance degradation over noise endurance level. From experimental observations, the WT is the most suitable in phase synchronization application of EEG signal, and the CD can be affordable in restricted application such as changing point detection for higher bands than ${\delta}$. Particularly, WT and CD can be used to detect the changing instant of brain function by indirectly estimating the phase changing point.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.269-272
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• 2015

this is the study of the human body antenna device which can detect the powder in a 360-degree on(under) the ground whether it is metal or nonmetal using superhigh frequency RF beam equipped with the body. and it is able to transmit the data of the detection of the powder, battle combats can share that among them. with its flexible roof radial antenna structure, it emits the superhigh frequency RF beam to the front and flank multiply, preprocesses through the powder preprocessing part. and with the non-linear regression model algorism engine part, reflecting the attenuation characteristics depend on the delayed time of degree of the signal power which is received to the superhigh frequency RF beam. so it is able to detect the signal of the most likely mine or powder based on the degree of the answer signal power according to the delayed time of the superhigh frequency RF beam. also, it can detect the powder whether it is metal or nonmetal, mine, dud, VBIED. it can increase the chance of detection about 90% more than existing mine detector.

• Journal of Radiation Protection and Research
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• v.37 no.2
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• pp.84-89
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• 2012

The purpose of this study was to compare radiation dose and image quality between low-dose (LDP) and standard-dose protocol (SDP). LDP (120 kVp, 30 mAs, 2-mm thickness) and SDP (120 kVp, 180 mAs, 1.2-mm thickness) images obtained from 61 subjects were retrospectively evaluated at level of carina bifurcation, using multi-detector CT (Brilliance 16, Philips Medical Systems). Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated at ascending aorta and infraspinatus muscle, from CT number and back-ground noise. Radiation dose from two protocols measured at 5-point using acrylic-phantom, and CT number and noise measured at 4-point using water-phantom. All statistical analysis were performed using SPSS 19.0 program. LDP images showed significantly more noise and a significantly lower SNR and CNR than did SDP images at ascending aorta and infraspinatus muscle. Noise, SNR and CNR were significantly correlated with body mass index (p<0.001). Radiation dose, SNR and CNR from phantom were significant differences between two protocols. LDP showed a significant reduction of radiation dose with a significant change in SNR and CNR compared with SDP. Therefore, exposure dose on LDP in clinical applications needs resetting highly more considering image quality.

• The Journal of the Korea Contents Association
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• v.19 no.12
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• pp.517-526
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• 2019

The purpose of this study is to find the optimal method for clinical application by analyzing image quality and radiation output according to parameter combination when using the Automatic Exposure Control (AEC). The experimental method combines 70, 81 kVp with sensitivity S200, S400, S800 and S1000 of the Automatic Exposure Control for Entrance Surface Dose (ESD), current volume, Signal to Noise Ratio (SNR), Contrast to Noise Ratio (CNR), Time-to-Radiation Dose Curve in abdomen and pelvis. And then, image quality and radiation output stability were evaluated. As a results, Entrance Surface Dose, current volume, Signal to Noise Ratio, Contrast to Noise Ratio decreased as the tube voltage and sensitivity were set higher. In addition, the higher tube voltage and sensitivity, the Time-to-Radiation Dose Curve showed a poor output stability. In conclusion, the higher the combination of tube voltage and sensitivity in the use of Automatic Exposure Control, the more problems can be seen in image quality and stability of the radiation output. Therefore, a relatively low combination of tube voltage and sensitivity showed that the image quality and radiation output stability could be optimized by minimizing the error range that would occur when the detector recognized a combination of parameters.

• Progress in Medical Physics
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• v.15 no.4
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• pp.202-209
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• 2004

Flat panel based digital radiography (DR) systems have recently become useful and important in the field of diagnostic radiology. For DRs with amorphous silicon photosensors, CsI(TI) is normally used as the scintillator, which produces visible light corresponding to the absorbed radiation energy. The visible light photons are converted into electric signal in the amorphous silicon photodiodes which constitute a two dimensional array. In order to produce good quality images, detailed behaviors of DR detectors to radiation must be studied. The relationship between air exposure and the DR outputs has been investigated in many studies. But this relationship was investigated under the condition of the fixed tube voltage. In this study, we investigated the relationship between the DR outputs and X-ray in terms of the absorbed energy in the detector rather than the air exposure using SPEC-l8, an X-ray energy spectrum model. Measured exposure was compared with calculated exposure for obtaining the inherent filtration that is a important input variable of SPEC-l8. The absorbed energy in the detector was calculated using algorithm of calculating the absorbed energy in the material and pixel values of real images under various conditions was obtained. The characteristic curve was obtained using the relationship of two parameter and the results were verified using phantoms made of water and aluminum. The pixel values of the phantom image were estimated and compared with the characteristic curve under various conditions. It was found that the relationship between the DR outputs and the absorbed energy in the detector was almost linear. In a experiment using the phantoms, the estimated pixel values agreed with the characteristic curve, although the effect of scattered photons introduced some errors. However, effect of a scattered X-ray must be studied because it was not included in the calculation algorithm. The result of this study can provide useful information about a pre-processing of digital radiography.