• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2020.07a
• /
• pp.576-578
• /
• 2020

최근 사용자에게 더욱 몰입감 있는 콘텐츠를 제공하기 위한 기술에 대한 관심이 증가하고 있으며 기존의 2D 콘텐츠와는 다른 새로운 방식인 3D 콘텐츠에 대한 연구가 활발히 진행되고 있으며 그 중 가장 대표적인 것이 Point Cloud 영상이라고 할 수 있다. Point Cloud의 경우 수많은 3차원 좌표를 가진 점들로 구성되어 있으며 각 점들마다 Attribute 값을 이용하여 색상 등의 표현이 가능한 구조로 이루어져 있다. 이러한 특성 때문에 Point Cloud 데이터는 방대한 용량을 가지고 있으며 기존의 2D 방식과 데이터 구조가 상이하기 때문에 새로운 압축 표준이 요구되었다. 이에 미디어 표준화 단체인 MPEG(Moving Picture Experts Group)에서는 MPEG-I(Immersive) 차세대 프로젝트 그룹을 이용하여 이러한 움직임에 대응하고 있다. MPEG-I의 part 5(Video-based Point Cloud Compression, V-PCC)에서는 객체를 대상으로 하여 기존의 비디오 코덱을 활용한 Point Cloud 압축 표준화를 진행중이다. V-PCC 데이터의 경우 기존의 2D 영상 데이터와 같이 전송을 통해 소비될 가능성이 아주 높기 때문에 이에 대한 고려가 필요하다. 현재 MPEG에서 표준화를 완료한 MMT(MPEG Media Transport)라는 전송 표준이 존재하기 때문에 이 기술을 활용 가능할 것으로 보인다. 따라서 본 논문에서는 Point Cloud 데이터를 압축한 V-PCC 데이터를 전송 표준 방식인 MMT를 이용하여 전송하는 방안에 대하여 제안한다.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.43 no.3 s.309
• /
• pp.51-59
• /
• 2006

In this paper, we propose an excellent ultrasonic transceiver system based on a QPSK modulation technique for underwater communication. The transmitter sends a still image at the level of 187dB re $1{\mu}Pa/V@1m$ through a power amplifier by driving an ultrasonic sensor. The receiver performs digital conversion at the 100kHz sampling frequency, demodulation and decoding process for the image sent from the transmitter through the underwater communication. We have shown that the processed image at the receiver is almost the same as the orignal one. The maximum detection distance of the system proposed in this paper is approximately 1.17km. To cope with the difficulties of transmission loss, this paper proposes, implements and analyzes important parameters of sensors and circuits used in the system. Most of the underwater communication has focused on the transmission of audio signal, but this paper suggests an efficient underwater communication system for still image transmission.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.4
• /
• pp.397-403
• /
• 2015

In this paper, a method of ISAR geometric calibration is represented by using impulse-radio UWB radar. The ir-UWB is good for using a signal processing in time domain, so, it does not occur a multi-path or coupling problem. If a signal that between antennas and target is assumed a plane wave, a center of rotation in ISAR geometry model can be estimated by using point target. Before image is reconstructed with sinogram, the center of rotation can be calculated by using least square fitting. This method can be obtained a more contrast image, and a maximum value of entropy of image. The method, that estimates a center of rotation in received data, will be used a initial setup of instruments or a periodic compensation to reconstruct image. It would be useful in medical, security and surveillance imaging equipments that have a fixed geometry.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.23 no.11
• /
• pp.1307-1314
• /
• 2012

To reduce the effects of clutters with subsurface inhomogenities in ground-penetrating radar(GPR) images, an eigenimage based signal-processing technique is presented. If the conventional eigenimage filtering technique is applied to B-scan images of a GPR survey, relatively homogeneous clutters such as antenna ringing, direct coupling between transmitting and receiving antennas, and soil-surface reflection, can be removed sufficiently. However, since random clutters of subsurface inhomogenities still remain in the images, target signals are distorted and obscured by the clutters. According to a comparison of the eigenimage filtering results, there is different coherency between subsurface clutters and target signals. To reinforce the pixels with high coherency and reduce the pixels with low coherency, the pixel-by-pixel geometric-mean process after the eigenimage filtering is proposed here. For the validity of the proposed approach, GPR survey for detection of a metal target in a randomly inhomogeneous soil is numerically simulated by using a random media generation technique and the finite-difference time-domain(FDTD) method. And the proposed signal processing is applied to the B-scan data of the GPR survey. We show that the proposed approach provides sufficient enhancement of target signals as well as remarkable reduction of subsurface inhomogeneous clutters in comparison with the conventional eigenimage filtering.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.27 no.3
• /
• pp.326-329
• /
• 2016

UAVs(Unmanned Aerial Vehicle) can be used in variant fields fornot only combat, but also recon, observation and exploration. Moreover, UAVs capacity can be expanded to impossible missions for existing surveillance system such as SAR(Synthetic Aperture Radar) technology that collecting images from all weather conditions. In recent days, with development of highly efficient IC and lightened system technology, there are significant increase of researches and demands to make SAR sensor as a payload of UAV. Therefore, this paper contains development process and results of small signal generator and RF device as a core module of SAR system based on the digital device of DDS.

• Journal of the Korea Computer Industry Society
• /
• v.6 no.5
• /
• pp.675-686
• /
• 2005

This paper proposes a new method of mathematically modeling and computer simulating television ghosts wherein television signals that have undergone multipath fading are generated without using approximations by considering the attenuation, time delay, phase, and timing jitter between consecutive frames. Conventional methods used polynomial interpolation or complex arithmetic to take into account the ghost phase, but our method uses only real arithmetic by employing the Hilbert transform and also reduces the computation time using the FFT (fast Fourier transform) algorithm. Furthermore, it is also possible to observe the transmit waveforms in both RF and IF ranges. Various ghost patterns generated in software provide for essential data required for the development of ghost canceling algorithms, and are deemed to be very useful in analyzing the constituent blocks of the transmitter and receiver chain in television broadcasting. The development of ghost cancelers needs to be preceded by the task of mathematically modeling ghosts and their extensive computer simulations.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.12
• /
• pp.2891-2898
• /
• 2013

CCSDS Standard is widely used in international space telecommunication area. In this standard, Encryption is realized using a unique hierarchical encryption protocol and satisfied security requirements of communication channels. For synchronization, encryption sync is attached in the beginning of encrypted data. But exceptional case(timing jittering, abnormal system shutdown, etc.) is occurred, receiving equipment cannot decrypt received data. In this paper, we propose a SES Alarmed link encryption synchronization method for sending warning signal to the transmitter when some problems have been occurred during the transmission and we also suggest optimum conditions for SES Alarm signal through performance analysis.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2012.05a
• /
• pp.213-215
• /
• 2012

The current Navigation System for the Visually Impaired Person has a short and limited communication distance and can't receive enough information from Visually Impaired Person to assist directly. In addition, because the path is dangerous and incomplete for the Visually Impaired Person, moving with White Stick is still inconvenient and dangerous. To solve this problem we implement communication that can send and receive video, voice, location information between the Visually Impaired Person's Android platform and assistant's PC.

• Proceedings of the Acoustical Society of Korea Conference
• /
• autumn
• /
• pp.357-358
• /
• 2004

생체 피부하 약 5mm이내 영역에 대한 고분해능의 B-모드 영상을 얻는 데 사용할 수 있는 축 방향 분해능 $30{\mu}m$ 이하인 VHF 대역 초음파 트랜스듀서로서 용융석영을 음향버퍼의 하여 그 양단에 송신용 2-2 composite와 수신용 P(VDF-TrFE)를 설치한 송수신 분리형의 집속 트랜스듀서의 구조를 새로이 제안하고, 그 전기적 음향적 특성을 시뮬레이션 하였다. 그 결과, 2-2 composite 투께 $18{\mu}m$와 P(VDF-TrFE) 두께 $12{\mu}m$의 트랜스듀서는 중심주파수 43.0MHz, 비대역 $74\%$이며, 삽입손실이 25dB인 비교적 우수한 트랜스듀서가 될 수 있음을 알았다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2017.04a
• /
• pp.185-188
• /
• 2017

본 연구는 미래 전장단말기와 무전기간 지휘관(자) 및 무전병 간 유선 연동에 따른 전투행동의 제한사항을 극복하기 위한 방법으로 강구되고 있는 무선(Bluetooth)을 이용한 데이터 전송 방법 중 Bluetooth의 세부 Profile과 전송 효율을 극대화하기 위한 최대 패킷크기, 분할 전송 간 패킷 전송 간격 등을 구체화하여 군 운용적으로 활용이 가능한지를 시험을 통해 검증하였다. 그 결과 Profile은 가장 보편적인 SPP를 적용하고, 응용계층에서 활용 가능한 최대 패킷 크기는 시험을 통해 1KB가 적정함을 확인하였다. 또한, 정지영상처럼 사이즈가 큰 데이터에 대한 분할 전송 간 패킷 전송 시간은 100ms로 설정함이 적절함을 확인하였다. 위 연구결과는 미래 전장단말기와 무전기 간 무선연동에서 즉각 적용이 가능할 것으로 판단된다.