• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.3
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• pp.139-146
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• 2004

A 2D/3D complex optical system and its vision inspection algerian is proposed and implemented as a single probe system for high speed, precise vision inspection of the solder pastes. One pass un length labeling algorithm is proposed instead of the conventional two pass labeling algorithm for fast extraction of the 2D shape of the solder paste image from the recent line-scan camera as well as the conventional area-scan camera, and the optical probe path generation is also proposed for the efficient 2D/3D inspection. The Moire interferometry-based phase shift algerian and its optical system implementation is introduced, instead of the conventional laser slit-beam method, for the high precision 3D vision inspection. All of the time-critical algorithms are MMX SIMD parallel-coded for further speedup. The proposed system is implemented for simultaneous 2D/3D inspection of 10mm${\times}$10mm FOV with resolutions of 10 ${\mu}{\textrm}{m}$ for both x, y axis and 1 ${\mu}{\textrm}{m}$ for z axis. Experiments conducted on several nBs show that the 2D/3D inspection of an FOV, excluding an image capturing, results in high speed of about 0.011sec/0.01sec, respectively, after image capturing, with $\pm$1${\mu}{\textrm}{m}$ height accuracy.

• The Journal of Engineering Geology
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• v.27 no.3
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• pp.217-231
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• 2017

The subsidence of ground in urban area can be caused by the occurrence of the cavity and the change in ground volumetric water content. The objective of this study is the detection of abnormal area of ground in urban area where the cavity or the change in ground volumetric water content is occurred by the ground penetrating radar signal. GPR survey is carried out on the test bed with a circular buried object. From the GPR survey, the signals filtered by the bandpass filtering are measured, and the methods consisting of gain function, time zero, background removal, deconvolution and display gain are applied to the filtered signals. As a result of application of the signal processing methods, the polarity of signal corresponds with the relation of electrical impedance of the cavity and the ground in test bed. In addition, the relative permittivity calculated by GPR signal is compared with that of predicted by volumetric water content of the test bed. The relative permittivities obtained from two different methods show similar values. Therefore, the abnormal area where the change in ground volumetric water content is occurred can be detected from the results of the GPR survey in case the depth of underground utilities is known. Signal processing methods and estimation of relative permittivity performed in this study may be effectively used to detect the abnormal area of ground in urban area.

• Journal of the Korean earth science society
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• v.34 no.1
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• pp.1-12
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• 2013

To effectively remove chaff echoes, which are often misidentified as precipitation echoes on weather radars, this study examines the relationship between the radar reflectivity and each of dual polarimetric parameters. The dual polarimetric parameters are collected only for the echo areas identified as chaff echoes on the NIMR X-band dual polarization radar. Overall, the polarimetric parameters (i.e., reflectivity, differential reflectivity, cross correlation coefficient, standard deviation of differential reflectivity and specific differential phase) for chaff echoes have a wider range of values than those for precipitation echoes and the chaff filaments tend to be horizontally oriented to radar beams. There appears to be a considerable overlap in the cross correlation coefficient range of chaff and precipitation echoes since some precipitation echoes have cross correlation coefficient lower than 0.8. Therefore, although the cross correlation coefficient is known to be a good variable in identifying and separating chaff echoes from precipitation echoes, it is suggested that additional care should be taken when using the cross correlation coefficient solely in removing chaff echoes.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.4
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• pp.159-166
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• 2016

In this paper, an active object tracking system basing on the pan/tilt-embedded stereo camera system is suggested and implemented. In the proposed system, once the face area of a target is detected from the input stereo image by using a YCbCr color model and phase-type correlation scheme and then, using this data as well as the geometric information of the tracking system, the distance and 3D information of the target are effectively extracted in real-time. Basing on these extracted data the pan/tilted-embedded stereo camera system is adaptively controlled and as a result, the proposed system can track the target adaptively under the various circumstance of the target. From some experiments using 480 frames of the test input stereo image, it is analyzed that a standard variation between the measured and computed the estimated target's height and an error ratio between the measured and computed 3D coordinate values of the target is also kept to be very low value of 1.03 and 1.18% on average, respectively. From these good experimental results a possibility of implementing a new real-time intelligent stereo target tracking and surveillance system using the proposed scheme is finally suggested.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2C
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• pp.156-165
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• 2006

In this paper, a new intelligent moving target tracking and surveillance system basing on the pan/tilt-embedded stereo camera system is suggested and implemented. In the proposed system, once the face area of a target is detected from the input stereo image by using a YCbCr color model and phase-type correlation scheme and then, using this data as well as the geometric information of the tracking system, the distance and 3D information of the target are effectively extracted in real-time. Basing on these extracted data the pan/tilted-imbedded stereo camera system is adaptively controlled and as a result, the proposed system can track the target adaptively under the various circumstance of the target. From some experiments using 480 frames of the test input stereo image, it is analyzed that a standard variation between the measured and computed the estimated target's height and an error ratio between the measured and computed 3D coordinate values of the target is also kept to be very low value of 1.03 and 1.18$\%$ on average, respectively. From these good experimental results a possibility of implementing a new real-time intelligent stereo target tracking and surveillance system using the proposed scheme is finally suggested.

• Investigative Magnetic Resonance Imaging
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• v.2 no.1
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• pp.83-88
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• 1998

Purpose : Authors correlated the three-dimensional time-of-flight MRA signal intensity characteristics and flow profile simulated by computer in an experimental flow phantom model. Materials and Methods : The three-dimensional time-of-flight MRA was performed in a fusiform flow phantom and analyzed the flow signal. computer assisted flow simulation was performed in same flow geometry. The MRA signal intensity and flow velocity distribution and direction was compared. Results : The flow was depicted as homogeneous signal internsity in inlet and outlet area and inhomogeneous signal intensity in fusiform area. Typically, the flow was depicted as target appearance in transition area to outlet. Whereas mean signal internsity decreased slowly in fusiform area, it rapidly dropped and resumed in transition area to outlet. In computer assisted flow simulation, Whereas there were flow velocity decrease and flow direction change to peripheral in entrance to fusiform area, ther were rapid flow velocity resuming and flow direction change to central in transition area to outlet. Conclusion : The signal loss and target appearance in transition area to outlet is characteristic of fusiform flow. These signal changes correlate with abrupt flow velocity and direction change well.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.3
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• pp.77-85
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• 2008

This work proposes a 12b 130MS/s 108mW $1.8mm^2$ 0.18um CMOS ADC for high-quality video systems such as TFT-LCD displays and digital TVs requiring simultaneously high resolution, low power, and small size at high speed. The proposed ADC optimizes power consumption and chip area at the target resolution and sampling rate based on a three-step pipeline architecture. The input SHA with gate-bootstrapped sampling switches and a properly controlled trans-conductance ratio of two amplifier stages achieves a high gain and phase margin for 12b input accuracy at the Nyquist frequency. A signal-insensitive 3D-fully symmetric layout reduces a capacitor and device mismatch of two MDACs. The proposed supply- and temperature- insensitive current and voltage references are implemented on chip with a small number of transistors. The prototype ADC in a 0.18um 1P6M CMOS technology demonstrates a measured DNL and INL within 0.69LSB and 2.12LSB, respectively. The ADC shows a maximum SNDR of 53dB and 51dB and a maximum SFDR of 68dB and 66dB at 120MS/s and 130MS/s, respectively. The ADC with an active die area of $1.8mm^2$ consumes 108mW at 130MS/s and 1.8V.

• Korean journal of communication and information
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• v.22
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• pp.77-106
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• 2003

As globalization of communication is going on and as the media have become increasingly central to the world economy, media policy matters have become the province of world economic organizations like the IMF and the WTO. The WTO service negotiation is focused primarily on the discriminatory and quantitative barriers associated with the trade of audiovisual services. Domestic measures such as subsidization, content regulation including quotas, and licensing requirements and restrictions on foreign ownership and control are at issues here. These measures have been successfully implemented by countries wishing to withstand competition from the American audiovisual industry. The debate about trade in audiovisual services is permeated by the unstated assumption that these programs are pure commodities whose production, distribution, exhibition and in turn, values are solely determined by the market forces. It is therefore presumed that liberalization of trade in audiovisual services will benefit all, serving cultural pluralism and diversity as well as economic efficiency. However, this assumption is not shared by developing countries, the recipients of U.S. television material. They argue audiovisual sector requires a social and cultural approach, since it plays a key role in the preservation of people's identity and social bonds. They claim that it is the each state's right to define its media policy and to implement it through the means it considers fit. These clashing views over the nature of the audiovisual material and the ways in which protect cultural pluralism and diversity do not confine to be the realm of theoretical debate. Each state's interest and motivation to protect its local industry and to have a competitive advantage in the international market is working in this battle. Consolidation with the countries like Australia, Canada, and EU nations, in favour of cultural exemption, seems to be the best policy for us. However, we are not entirely free from the WTO pressures, considering relation to the U. S. This study analyzes Korean Broadcasting Law compared with those of other OECD countries and tries to propose some strategical guidelines facing WTO service negotiation in the area of broadcasting.

• Korean Journal of Remote Sensing
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• v.21 no.4
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• pp.303-316
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• 2005

Strong radar returns were observed in oyster sea farms, and coherent interferometric pairs were successfully constructed. Tide height in coastal area is possible to be measured by using interferometric phase and intensity of SAR data. This SAR application technique for measuring the tide height in the near coastal zone can be further improved when applied to double bounce dominant areas. In this paper, we investigate the characteristics of polarimetric signature in the oyster farm structures. Laboratory experiments were carried out using Ku-band according to the target scale. Radar returns from vertical poles are stronger than those from horizontal Pole by 10.5 dB. Single bounce components were as strong as double bounce components and more sensitive to antenna look direction. Double bounce components show quasi-linear relation with the height of vertical poles, which implies double bounce is more useful to determine water level than total power. A L-band NASA/IPL airborne SAR (AIRSAR) image was classified into single-, double-bounce, and volume scattering components. It is observed that oyster farms are not always characterized by double bounced scattering. Double bounce is a main scattering mechanism in oyster farms standing above seawater, while single bounce is stronger than double bounce when bottom tidal flats are exposed to air. Ratios of the normalized single to double bounce components in the former and latter cases were 0.46 and 5.62, respectively. It is necessary to use double bounce dominant sea farms for tide height measurement by DInSAR technique.

• Radiation Oncology Journal
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• v.28 no.4
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• pp.238-248
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• 2010

Purpose: To compare the dose distributions between three-dimensional (3D) and four-dimensional (4D) radiation treatment plans calculated by Ray-tracing or the Monte Carlo algorithm, and to highlight the difference of dose calculation between two algorithms for lung heterogeneity correction in lung cancers. Materials and Methods: Prospectively gated 4D CTs in seven patients were obtained with a Brilliance CT64-Channel scanner along with a respiratory bellows gating device. After 4D treatment planning with the Ray Tracing algorithm in Multiplan 3.5.1, a CyberKnife stereotactic radiotherapy planning system, 3D Ray Tracing, 3D and 4D Monte Carlo dose calculations were performed under the same beam conditions (same number, directions, monitor units of beams). The 3D plan was performed in a primary CT image setting corresponding to middle phase expiration (50%). Relative dose coverage, D95 of gross tumor volume and planning target volume, maximum doses of tumor, and the spinal cord were compared for each plan, taking into consideration the tumor location. Results: According to the Monte Carlo calculations, mean tumor volume coverage of the 4D plans was 4.4% higher than the 3D plans when tumors were located in the lower lobes of the lung, but were 4.6% lower when tumors were located in the upper lobes of the lung. Similarly, the D95 of 4D plans was 4.8% higher than 3D plans when tumors were located in the lower lobes of lung, but was 1.7% lower when tumors were located in the upper lobes of lung. This tendency was also observed at the maximum dose of the spinal cord. Lastly, a 30% reduction in the PTV volume coverage was observed for the Monte Carlo calculation compared with the Ray-tracing calculation. Conclusion: 3D and 4D robotic radiotherapy treatment plans for lung cancers were compared according to a dosimetric viewpoint for a tumor and the spinal cord. The difference of tumor dose distributions between 3D and 4D treatment plans was only significant when large tumor movement and deformation was suspected. Therefore, 4D treatment planning is only necessary for large tumor motion and deformation. However, a Monte Carlo calculation is always necessary, independent of tumor motion in the lung.