• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.2
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• pp.248-256
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• 2007

Recently, the network Infrastructure grows rapidly and the digital image compression technique has made remarkable progress. Therefore, the demand of the real-time image surveillance system which uses a network camera server has been increasing. Network Camera Server has emerged as an attractive alternative to the CCTV for the wireless video surveillance. In this article, the model of JPEG Streamer for collecting and delivering JPEG image is designed and realized as a key module for the wireless video surveillance system. The thread pool and shared memory have been used to improve the stability and efficiency of the JPEG Streamer. In addition, the concept of double buffering is of much benefit to improve the quality of real-time image. In this article, the wireless video surveillance system by using JPEG Streamer is suggested to send the real-time image through the wireless internet with the personal digital assistance (PDA).

• Journal of Internet Computing and Services
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• v.22 no.2
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• pp.51-58
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• 2021

Three degrees of freedom plus(3DoF+) and six degrees of freedom(6DoF) system, which supports a user's movements in graphical and natural scene-based virtual reality, requires multiple high-quality and high-resolution videos to provide immersive media. Previous video quality assessment methods are not appropriate for the 3DoF+ and 6DoF system assessment because different types of artifacts occur in these systems which are not shown in the traditional video compression. This paper provides the performance assessments of several quality assessment methods in 3DoF+ system. Furthermore, this paper presents a super metric, which combines multiple quality assessment methods, thereby it showed a higher correlation coefficient with the subjective quality assessment than the previous methods. Experimental results on 3DoF+ immersive video showed 0.4513 gain on correlation coefficient with subjective quality assessment compared to that of peak signal-to-noise ratio(PSNR).

• Journal of Digital Convergence
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• v.17 no.7
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• pp.207-214
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• 2019

This study was designed to find effective CPR education methods by comparing and analyzing the quality of Field-Focus Type (FFT) CPR using SimPad and the quality of Video Self-lnstruction(VSI) CPR for the learners. The data collection were conducted from November 28, 2018 to December 5, 2018, on 64 first graders who completed CPR lectures at universities located in G metropolitan city, and analyzed using the SPSS ver. 23.0. The results of the study, Field Focus Type (FFT) CPR showed higher quality of Video Self-lnstruction (VSI) CPR in areas such as CPR total score, chest compressions score, chest compressions dept, chest compressions rate, chest compression velocity, total ventilation score, and Total number of ventilation than that of the subjects. Therefore, using Field Focus Type CPR (FFT) education law was found to improve the quality of cardiopulmonary resuscitation compared to the existing Video Self-lnstruction CPR (VSI) education method, and it is believed that it can be used as a basic data for cardiopulmonary resuscitation education in the future.

• Journal of Broadcast Engineering
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• v.28 no.1
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• pp.100-108
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• 2023

In hybrid block-based video coding, transform coding converts spatial domain residual signals into frequency domain data and concentrates energy in a low frequency band to achieve a high compression efficiency in entropy coding. The state-of-the-art video coding standard, VVC(Versatile Video Coding), uses DCT-2(Discrete Cosine Transform type 2), DST-7(Discrete Sine Transform type 7), and DCT-8(Discrete Cosine Transform type 8) for primary transform. In this paper, considering that DCT-2, DST-7, and DCT-8 are all linear transformations, we propose an inverse transform that reduces the number of multiplications in the inverse transform by using the linearity of the linear transform. The proposed inverse transform method reduced encoding time and decoding time by an average 26%, 15% in AI and 4%, 10% in RA without the increase of bitrate compared to VTM-8.2.

• Journal of Korea Society of Industrial Information Systems
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• v.15 no.2
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• pp.31-39
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• 2010

VoD(Video-on-Demand) servers have to provide timely processing guarantees for continuous media and reduce the storage and bandwidth requirements for continuous media. The compression techniques make the bit rates of compressed video data significantly variable from frame to frame. A VoD system should be able to provide the client with interactive operations such as fast forward and fast rewind in addition to normal playback of movie. However, interactive operations require additional resources such as storage space, disk bandwidth, memory and network bandwidth. In a stored video application such as VoD system, it is possible that a priori disk access patterns can be used to reserve the system resources in advance. In addition, clients of VoD server spend most of their time in playback mode and the period of time spent in interactive mode is relatively small. In this paper, I present the new buffer management scheme that provides efficient support for interactive operations in a VoD server using variable bit rate continuous media. Simulation results show that our strategy achieves 34% increase of the number of accepted clients over the LRU strategy.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1730-1733
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• 1997

In this paper, a realization of a subband coding with TMS320C80 is studied. TMS320C80 is a multi-media processor specially designed for an image process. A main topic of this paper, as mentioned above, is an application of TMS320C80 to subband coding. Subband coding is the coding that devides full image to several subbands and encodes each subband with different coding methods. As using that methods, good image compression can be obtained. First above all, goal of this paper deals with TMS320C80 in coding still image and useds it in expending it's application to 3-D video coding.

• Proceedings of the IEEK Conference
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• 2000.11d
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• pp.45-48
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• 2000

In this paper, we propose a region-based segmentation algorithm to extract human face area using a window function and neural networks. Furthermore, we apply the erosion and dilation to remove small error areas. By applying the window function, it is possible to reduce error. In particular, false segmentation of the eye and the lip can be considerably reduced. Experiments show promising results and it is expected that the Proposed method can be applied to video conference and still image compression.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.701-704
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• 2000

In this paper, we focus on digital watermarking for color images. At first, in order to embed the watermark signal in color image, we converted RGB color space to YCbCr color space which is a world-wide digital component video standard. In addition, we adopted the acceptable degree of color difference in order to keep the invisibility.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.11a
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• pp.467-470
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• 2000

Vector quantization (VQ) is widely used in many high-quality and high-rate data compression applications such as speech coding, audio coding, image coding and video coding. When the size of a VQ codebook is large, the computational complexity for the full codeword search method is a significant problem for many applications. A number of complexity reduction algorithms have been proposed and investigated using such properties of the codebook as the triangle inequality. This paper proposes a new structured VQ search algorithm that is based on a multi-stage structure for searching for the best codeword. Even using only two stages, a significant complexity reduction can be obtained without any loss of quality.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.11a
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• pp.569-573
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• 1998

본 논문에서는 움직임 보상과 웨이브릿 변환 부호화 기법을 이용하여 비디오 신호의 데이터를 압축하고자 한다. 비디오 신호에 대한 인간 시각 특성을 분석하여 큰 이득을 주지 못하는 과정을 생략하고 인간의 눈에 민감하지 않은 정보를 생략함으로써 화질의 저하 없이 비디오 신호를 높은 비율로 압축한다. 제안한 방법은 움직임이 발생되는 정도와 크기에 매우 의존적으로, 움직임이 많은 비디오 신호에 더욱 적합하나 움직임이 작은 경우에도 저주파 대역들의 움직임 보상에 의한 이득이 크기 때문에 모든 영상에 대해서 적용 가능한 방법이다. 'football'과 'Popple'을 대상으로 한 컴퓨터 시뮬레이션결과, 프레임당 30:1 정도의 압축하에서 높은 재생화질을 얻을 수 있었다.