• Journal of Broadcast Engineering
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• v.12 no.3
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• pp.222-229
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• 2007

According to the advancement of multimedia compression technologies, high quality multi-media services are easily found in common life. Along with this situation, 5.1-channel audio service also has expanded the application area to home theater system and car theater system and consumer can easily take a chance to experience the feeling of 5.1-channel audio. On the other hand, terrestrial DMB service has been launched in Korea from Dec. 2005 as a handhold multi-media broadcasting service. However, multi-channel audio was not considered due to the insufficiency of bandwidth and the handhold usage. Lately, MPEG is standardizing high efficiency multi-channel audio compression technology for handheld broadcasting service, and several trial for application is introduced in Europe. In this paper, we would like to explain multi-channel audio compression technology, describe the implementation of the verification system for the multi-channel audio service over T-DMB and investigate the possibility of further realization of the service.

• Korean Journal of Agricultural Science
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• v.38 no.4
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• pp.731-737
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• 2011

In the modern society, GIS-based decision support system has been used in evaluating environmental issues and changes due to spatial and temporal analysis capabilities of the GIS. However without proper manual of these systems, its desired goals could not be achieved. In this study, audio-visual SWAT tutorial system was developed to evaluate its effectives in learning the SWAT model. Learning effects was analyzed after in-class demonstration and survey. The survey was conducted for $3^{rd}$ grade students with/without audio-visual materials using 30 questionnaires, composed of 3 items for trend of respondent, 5 items for effects of audio-visual materials, and 12 items for effects of with/without manual in learning the model. For group without audio-visual manual, 2.98 out of 5 was obtained and 4.05 out of 5 was obtained for group with audio-visual manual, indicating higher content delivery with audio-visual learning effects. As shown in this study, the audio-visual learning material should be developed and used in various computer-based modeling system.

• Journal of the Korea Society of Computer and Information
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• v.3 no.4
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• pp.10-18
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• 1998

Video information is an important component of multimedia system such as Digital Library. World-Wide Web(WWW) and Video-On-Demand(VOD) service system. It can support various types of information because of including audio-visual, spatial-temporal and semantics information. In addition, it requires the ability of retrieving the specific scene of video instead of entire retrieval of video document. Therefore, so as to support a variety of retrieval, this paper models metadata using video document structure information that consists of hierarchical structure, and designs database schema that can manipulate video document.

• Journal of the Institute of Convergence Signal Processing
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• v.16 no.2
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• pp.35-39
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• 2015

Auditory and visual stimuli presented in the peripheral visual field were perceived as spatially coincident when the auditory stimulus was presented five to seven degrees outwards from the direction of the visual stimulus. Furthermore, judgments of the perceived distance between auditory and visual stimuli presented in the periphery did not increase when an auditory stimulus was presented in the peripheral side of the visual stimulus. As to the origin of this phenomenon, there would seem to be two possibilities. One is that the participants could not perceptually distinguish the distance on the peripheral side because of the limitation of accuracy perception. The other is that the participants could distinguish the distances, but could not evaluate them because of the insufficient experimental setup of auditory stimuli. In order to confirm which of these two alternative explanations is valid, we conducted an experiment similar to that of our previous study using a sufficient number of loudspeakers for the presentation of auditory stimuli. Results revealed that judgments of perceived distance increased on the peripheral side. This indicates that we can perceive discrimination between audio and visual stimuli on the peripheral side.

• The Journal of the Acoustical Society of Korea
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• v.24 no.2
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• pp.68-77
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• 2005

The purpose of a spatial audio system is to give a listener an impression as if he were present in a recorded environment when its sound is reproduced. For this purpose a dummy head microphone is generally used. Because of its human-like shape, dummy head microphone can reproduce spatial images through headphone reproduction. However, its shape and size are restriction to public use and it is difficult to convert the output signal of dummy head microphone into a multi-channel signal for multi-channel environment. So, in this paper, we propose a multi-channel 3D microphone technology. The multi-channel 3D microphone acquire a spatial audio using five microphones around a horizontal plane of a rigid sphere and through post processing, it can reproduce various reproduction signals for headphone, stereo, stereo dipole, 4ch and 5ch reproduction environments. Because of complex computation, we implemented H/W based post processing system. To verily the Performance of the multi-channel 3D microphone, localization experiments were Performed. The result shows that a front/back confusion, which is the one of common limitations of conventional dummy head technology, can be reduced dramatically.

• Journal of Broadcast Engineering
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• v.11 no.2 s.31
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• pp.181-190
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• 2006

Technology for compressing low-bitrate multichannel audio coding should be developed owing to the increasing need of consumer for multichannel audio contents and services. To meet this requirement, MPEG has standardized MPEG Surround. In this paper, we introduce status on MPEG Surround standardization and analyze techniques adopted in the current MPEG Surround.

• Journal of Broadcast Engineering
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• v.21 no.3
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• pp.369-379
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• 2016

This paper deals with an efficient method for skipping inter-channel phase differences (IPD) in the MPEG surround of the unified speech and audio coding (USAC). Based on the psycho-acoustic sensitivity on the IPD, we estimate a threshold on IPD, below which we can not notice degradation in spatial cue. We propose an IPD skip method, in which any IPDs within the threshold are set to zero and are not transmitted. The proposed IPD skip method gives about 38% savings in terms of bit amount for IPD. Nevertheless, in the MUSHRA test, the proposed method does not show any noticeable degradation in the decoded audio quality.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.241-242
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• 2006

MPEG Surround is an audio coding technology that represents multi-channel audio signal with downmixed audio signal(s) and very low bitrate side information based on Binaural Cue Coding. The side information consists of Inter-Channel Level Difference, Inter-Channel Correlation, and payloads. These two parameters are correspondent to the well-known spatial parameters in psycho-acoustics, Inter-aural Level Difference (ILD) and Inter-Aural Cross Correlation (IACC). Though ICLD is to provide perceptually equivalent ILD to the listener, however, the ILD of the original multi-channel audio signal and that of the MPEG Surround encoded signal was different. The difference between two ILD values is defined as ILD Distortion (ILDD). This paper provides how ILDD can be applied to enhance sound quality in MPEG Surround and how much ILDD is decreased.

• The Journal of the Acoustical Society of Korea
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• v.31 no.5
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• pp.332-339
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• 2012

Beamspace transform algorithm transforms spatial-domain data - such as x, y, z dimension - into incidence-angle-domain data, which is called beamspace-domain data. The beamspace transform method is generally used in source localization and tracking, and adaptive beamforming problem. When the beamspace transform method is used in multichannel audio source separation, the inverse beamspace transform is also important because the source image have to be reconstructed. This paper studies the beamspace transform and inverse transform algorithms for multichannel audio source separation system, especially for the beamspace-domain multichannel NMF algorithm.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.150-157
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• 2009

In this paper, we propose a person tracking based multi-channel audio panning system for multi-view broadcasting services. Multi-view broadcasting is to render the video sequences that are captured from a set of cameras based on different viewpoints, and multi-channel audio panning techniques are necessary for audio rendering in these services. In order to apply such a realistic audio technique to this multi-view broadcasting service, person tracking techniques which are to estimate the position of users are also necessary. For these reasons, proposed methods are composed of two parts. The first part is a person tracking method by using ultrasonic satellites and receiver. We could obtain user's coordinates of high resolution and short duration about 10 mm and 150 ms. The second part is MPEG Surround parameter-based multi-channel audio panning method. It is a method to obtain panned multi-channel audio by controlling the MPEG Surround spatial parameters. A MUSHRA test is conducted to objectively evaluate the perceptual quality and measure localization performance using a dummy head. From the experiments, it is shown that the proposed method provides better perceptual quality and localization performance than the conventional parameter-based audio panning method. In addition, we implement the prototype of person tracking based multi-view broadcasting system by integrating proposed methods with multi-view display system.