• Proceedings of the KOSOMBE Conference
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• v.1990 no.11
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• pp.15-18
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• 1990

In abdominal NMR imaging the respiratory ordering techniques have been successfully used to remove the ghosting artifacts arising from the respiratory motion. In the existing respiratory ordering schemes, however, it is generally accepted that blurring of the moving parts still remains as in the signal averaging technique. A new optimal respiratory ordering scheme which can correct the blurring as well as the ghosting artifacts is theoretically derived through the analysis of the phase encoding directional motion effects in Fourier imaging. The performance of the optimal respiratory ordering scheme is experimentally confirmed together with a suboptimal ordering scheme which is suggested as a compromise for the practicality.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.572-577
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• 1994

The automatic detection of artifacts and vigilance level as for pre-processing of the automatic EEG interpretation are discussed. The equations for detecting artifacts and vigilance level were determined such that they would conform to the procedures that an EEGer (one of the authors, H.S.) usually adopts for visual inspection of the actual EEG record. The automatic EEG interpretation was found to be improved by the newly developed pre-processing method even will artifact contamination or in drowsy condition of the subjects.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.86-87
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• 2009

LED backlight for LCD TV is a great alternative to CCFL backlight due to its low power consumption and flexible arrangement. Various LED backlight configurations are being used to control the backlight locally in order to achieve both power efficiency and high contrast. However, the relatively small spatial resolution of the backlight system results in showing artifacts of backlight control that is acknowledgeable to human vision. Moreover, such artifacts get worse between temporal frames. In this paper we present a method of decreasing such temporal artifacts with a Human Visual System(HVS) approach to minimize distortion caused by local backlight dimming.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.736-740
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• 1991

EEG(Electroencephalogram) background signals can be represented as the sun of a conventional AR(Autoregressive) process and an innovation process, or a prediction error process. We have seen that conventional estimation techniques. such as least square estimates(LSE) or Gaussian maximum likelihood estimates(MLE-G) are optimal when the innovation process satisfies the Gaussian or presumed distribution. But when the data are contaminated by outliers, or artifacts, these assumptions are not met and conventional estimation techniques can badly fall and be strongly biased. It is known that EEG can be easily affected by artifacts. So we suggest a robust estimation technique which considerably performs well against those artifacts.

• KOMUNHWA
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• no.56
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• pp.147-180
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• 2000

This study has been investigated to use base research data of archaeology and conservation science for cultural properties about iron artifacts from Kimhae Yangdong-Ri tombs as metallurgical research. 1. Iron artifacts from Kimhae Yangdong-Ri tombs had be

• Imaging Science in Dentistry
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• v.44 no.1
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• pp.81-84
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• 2014

This report described a case in which diagnostic radiographs showed irregular dense radiopaque strings and curved lines in the head and neck area. These artifacts could lead to misinterpretation since they may obscure anatomical structures and/or mask critical structures/pathologies. A more detailed history of the patient indicated that these strings originated from a facelift procedure in which a gold-wire technique was used. Considering that such intervention may cause a radiodiagnostic burden, it should be included in the anamnesis prior to radiography.

• Journal of the Korean Magnetic Resonance Society
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• v.2 no.1
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• pp.59-65
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• 1998

The correction of image artifacts due to misadjustment in tuning of RF coils (tip angle) and in the RF single sideband spectrometer was investigated using phase cycling of the $\pi$/2 and $\pi$ pulses in spin-echo sequences. A general procedure was developed for the systematic design of phase cycles that select desirable coherence transfer pathways. To analyze a phase cycling sequence, changes in the coherence level and phase factor for each RF pulse in the spin-echo cycle must be determined. Four different phase cycling schemes (FIXED, ALTERNATE, FORWARD, REVERSED) to suppress unwanted signal components such as mirror and ghost images were evaluated using two signal acquisitions. When the receiver phase factor is cycled counter-clockwise (REVERSED), these artifacts are completely removed.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.316-320
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• 2009

In this paper, a reference-free perceptual quality metric is proposed for image assessment. It measures the amount of overall blockiness and blurring in the image. And edge-oriented artifacts, such as ringing, mosaic and staircase noise are also considered. In order to give a single quality score, the individual artifact scores are adaptively combined according to the difference between the edge-oriented artifacts and other artifacts. The quality score obtained by the proposed algorithm shows strong correlation with the MOS values by VQEG.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.12
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• pp.146-153
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• 2009

One of the most important issues in the wearable healthcare sensors is to minimize the motion artifacts in the vital signals for continuous monitoring. This paper presents a reflected type photoplethysmograph (PPG) sensor for monitoring heart rates at the artery of the wrist. Active noise cancellation algorithm was applied to compensate the distorted signals by motions with Least Mean Square (LMS) adaptive filter algorithms, using acceleration signals from a MEMS accelerometer. Experiments with a watch type PPG sensor were performed to validate the proposed algorithm during typical daily motions such as walking and running. The developed sensor is suitable for ubiquitous healthcare system and monitoring vital arterial signals during surgery.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.351-354
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• 2002

DVR(Digital Video Recorder), a recently popular visual monitoring system, is required to support multi camera channel display(upto 16 channels) with various display modes in real-time. For such a multichannel display system, it is well known that tearing artifacts become more serious. Thus, one needs to design a display system for DVR so that it does not show tearing artifacts as much as possible, but keeps real-time display speed. In this paper, we present our efforts in designing and implementing a display system which rarely ever shows tearing artifacts, but without degradation of required real-time display speed, and which displays character information stably without blinking.