• Journal of Navigation and Port Research
• /
• v.27 no.2
• /
• pp.145-153
• /
• 2003

The presence-feeling enhancement method of a Virtual Reality (VR) simulator is proposed in this paper. The method is to increase realistic human feeling by mutual synergy effect between stereoscopic image and three-dimensional (3D) sound. In order to test the influence of mutual synergy effect, subject assessment with five university students is carried out using VR ship simulator having PC monitor and LCD shutter glasses. It I found that the averaged scale value of image naturalness is increased by 0.5 from $I_{nat}$=3.1 to 3.6 when blending stereoscopic images with 3D sound, and the averaged score value of sound localization is increased by 10% from $A_{SL}$ = 70~75% to $A_{SL}$ = 80~85% when blending 3D sound with stereoscopic image. In conclusion, the results show that the proposed method is able to increase the presence feeling in the VR simulator.

• The Journal of the Acoustical Society of Korea
• /
• v.30 no.5
• /
• pp.255-264
• /
• 2011

The Head Related Transfer Function (HRTF) means a process related to acoustic transmission from 3d space to the listener's ear. In other words, it contains the information that human can perceive locations of sound sources. So, we make virtual 3d sound using HRTF, despite it doesn't actually exist. But, it can deteriorate some three-dimensional effect by the confusion between front and back directions due to the non-individual HRTF depending on each listener. In this paper, we proposed the new algorithm to reduce the confusion of sound image localization using human's acoustic characteristics. The frequency spectrum and global masking threshold of 3d sounds using HRTF are used to calculate the psychoacoustical differences among each directions. And perceptible cues in each critical band are boosted to create effective 3d sound. As a result, we can make the improved 3d sound, and the performances are much better than conventional methods.

• The Journal of the Korea Contents Association
• /
• v.5 no.6
• /
• pp.74-86
• /
• 2005

In this paper, we proposed an algorithm for the approximation of high order FIR filters by low order IIR filters to efficient implementing two channel 3-D surround sound systems using Head-related transfer functions(HRTFs). The algorithm is based on a concept of the balanced model reduction. The binaural sounds using the approximated HRTFs are reproduced by headphone, and serves as a cue of sound image localization. HRTFs of dummy-head are approximated from 512-order FIR filters by 32-order IIR filters and compare with each other. .Experiment of sound image are carried out for 10 participants. We perform the experiment based on computer simulation and hardware experiment with TMS320C32. The results of the experiments show that the localization using the approximated HRTFs is the same accuracy as the case of FIR filters that simulate the HRTFs.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.3 no.3
• /
• pp.541-546
• /
• 1999

The head-related transfer function (HRTF), which expresses the acoustic process from the sound source to the human ears in the free field, contains critical informations which the location of the source can be traced. It also makes it possible to realize multi-dimensional acoustic system that can approximately generate non-existing sound source. The use of non-individual, common HRTF brings performance degradation in localization ability such as front-back judgment error, elevation judgment error. In this paper, we have reduced the error on vertical plane by increasing the spectral notch level. The performance of the proposed method was Proved through subjective test that it is Possible to improve the ability to locate stationary/moving source.

• Proceedings of the IEEK Conference
• /
• 2002.07a
• /
• pp.117-120
• /
• 2002

A single DSP implementation of 3D sound movement is described. With the use of a realtime 3D acoustic image localization algorithm, an efficient approach is devised for synthesizing the 3D sound movement by interpolating only two parameters of "delay" and "gain". Based on this algorithm, the realtime 3D sound synthesis is performed by a commercially available 16-bit fixed-point DSP with computational labor of 65 MIPS and memory space of 9.6k words, which demonstrates that the algorithm call be used even for the mobile applications.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.05a
• /
• pp.611-616
• /
• 2003

The headphone is regarded as the most effective means for reproducing 3-dimentional virtual sound due to its channel separation property. However, there still exist several serious problems in headphone reproduction, such as, 'front-back confusion' and in-head localization'. These well-known problems are in general assessed by the subjective test that is based on human judgment. In this paper, an objective test is conducted in parallel with the subject test in order to validate the objective reproduction performance. Such a combined approach may be a more scientific and systematic approach to the reproduction performance.

• Journal of Institute of Control, Robotics and Systems
• /
• v.21 no.4
• /
• pp.315-320
• /
• 2015

This paper describes the implemenation of localization and visualization scheme to find out an ultrasonic source caused by defects of a power distribution line equipment. To increase the fault detection performance, $2{\times}4$ sensor array is configured with MEMS ultrasonic sensors, and from the sensor signals aquired, the azimuth and elevation angles of the ultrasonic source is estimated based on the delay-sum beam forming method. Also, to visualize the estimated location, it is marked on the background image. Experimental results show applicability of the present technique.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.6
• /
• pp.1201-1206
• /
• 2009

According to a lot of investigations, distance perception is influenced by many important cues such as sound pressure level, reflections from the room surface, binaural difference (ITD and ILD), a kind of sound source, and head related transfer functions (HRTF). Two psychoacoustical experiments on auditory distance perception were conducted to examine the effectiveness of the sound pressure level loudness as one of the physical cues in the auditory distance perception under a constant loudspeaker's output level and a constant sound level at the subject's position in the absence of reflections in an anechoic room. Our experimental results showed that the perceived distance of sound image is closer than actual sound source distance with the constant loudspeaker's output level and the constant sound level. Futhermore, the perceived distance of a sound image with constant sound level increased when the actual distance increases up to approximately 2 m while the perceived distance saturated when the sound source distance exceed 2 m. On the other hand, when the condition of loudspeaker's output level was kept constantly, the perceived distance of sound image increased up to around 3m, longer than the conditions of constant sound level at the subject's position. We found that the change in the loudness as a function of distance plays an important role in the auditory distance perception in the absence of reflections..

• Journal of Satellite, Information and Communications
• /
• v.8 no.4
• /
• pp.43-46
• /
• 2013

Active use of images in the same place as the religion according to the height of the screen is determined by the height of the main speakers. This causes the 'sound image mismatch' and 'bass boost' sound like a failure occurs. Front seats are good seats in visual acoustics is a bad place. To minimize these obstacles acoustical speakers to actively apply the front fill needed. Higher sound pressure difference between the main speaker and the distance must be determined in accordance with the appropriate capacity. Actively using the front speakers to the sound image field by implementing the agreement to increase the concentration of sound. The relatively high inflow enhance alto lacking the front seat can be implemented evenly in the frequency response. Column in front of the main seat of the main speakers to supplement the deficiencies can be implemented more comfortable acoustic environment. Front fill speaker needs to be actively introduced, thereby presenting a detailed estimate, is needed.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.1165-1166
• /
• 2008

In this paper, we propose a system for accident prevention of intelligent farm machine. Especially, efficient implementation method of accident prevention system using image sensor and sound source localization recognition system is proposed.