• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.117.2-117
• /
• 2001

In this paper, 3D sound rendering using multichannel speakers is studied. Virtual 3D sound technology has mainly been researched with binaural system. The conventional binaural sound systems reproduce the desired sound at two arbitrary points using two speakers in 3DD space. However, it is hard to implement the localization of virtual source at back/front and top/below positions because the HRTF of an individual is unique just like the fingerprint. Most of all, the HRTF is highly sensitive to the elevation change. Multichannel sound systems have mainly been used to reproduce the sound field picked up over a certain volume rather than at specific points. Moreover, multichannel speakers arranged in 3-D space produce a much better performance of ...

• The Journal of the Acoustical Society of Korea
• /
• v.35 no.1
• /
• pp.35-41
• /
• 2016

Based on correlation and least square method, a closed-form algorithm for estimating the location of mixed far-field and near-field source is presented using the Uniform Circular Array (UCA). Recently, for a homogeneous circular arrangement case, a correlation based closed-form algorithm is proposed to estimate 2-D angle (azimuth, elevation) and the extended algorithm is proposed to 3-D location (azimuth, elevation, range). These algorithms assume the far-field source or near-field source only. Therefore, for mixed source localization, the proposed algorithm estimates source location with the assumption of far-field source, and then estimates the range to distinguish the far-field from the near-field source. For both cases, numerical experiments have been performed, which confirmed the validity of the proposed algorithm.

• Advances in robotics research
• /
• v.2 no.1
• /
• pp.45-57
• /
• 2018

Even though the popularity of projection mapping continues to increase and it is being implemented in more and more settings, most current projection mapping systems are limited to special purposes, such as outdoor events, live theater and musical performances. This lack of versatility arises from the large number of projectors needed and their proper calibration. Furthermore, we cannot change the positions and poses of projectors, or their projection targets, after the projectors have been calibrated. To overcome these problems, we propose a projection mapping method using a projector robot that can perform projection mapping in more general or ubiquitous situations, such as shopping malls. We can estimate a projector's position and pose with the robot's self-localization sensors, but the accuracy of this approach remains inadequate for projection mapping. Consequently, the proposed method solves this problem by combining self-localization by robot sensors with position and pose estimation of projection targets based on a 3D model. We first obtain the projection target's 3D model and then use it to accurately estimate the target's position and pose and thus achieve accurate projection mapping with a projector robot. In addition, our proposed method performs accurate projection mapping even after a projection target has been moved, which often occur in shopping malls. In this paper, we employ Ubiquitous Display (UD), which we are researching as a projector robot, to experimentally evaluate the effectiveness of the proposed method.

• Journal of Positioning, Navigation, and Timing
• /
• v.1 no.1
• /
• pp.35-43
• /
• 2012

The UGV is one of the special field robot developed for mine detection, surveillance and transportation. To achieve successfully the missions of the UGV, the accurate and reliable navigation data should be provided. This paper presents design and implementation of multi-sensor-based open architecture integrated navigation for localization of UGV. The presented architecture hierarchically classifies the integrated system into four layers and data communications between layers are based on the distributed object oriented middleware. The navigation manager determines the navigation mode with the QoS information of each navigation sensor and the integrated filter performs the navigation mode-based data fusion in the filtering process. Also, all navigation variables including the filter parameters and QoS of navigation data can be modified in GUI and consequently, the user can operate the integrated navigation system more usefully. The conventional GPS/INS integrated system does not guarantee the long-term reliability of localization when GPS solution is not available by signal blockage and intentional jamming in outdoor environment. The presented integration algorithm, however, based on the adaptive federated filter structure with FDI algorithm can integrate effectively the output of multi-sensor such as 3D LADAR, vision, odometer, magnetic compass and zero velocity to enhance the accuracy of localization result in the case that GPS is unavailable. The field test was carried out with the UGV and the test results show that the presented integrated navigation system can provide more robust and accurate localization performance than the conventional GPS/INS integrated system in outdoor environments.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.16 no.3
• /
• pp.107-111
• /
• 2021

A 3D point cloud map is an essential elements in various fields, including precise autonomous navigation system. However, generating a 3D point cloud map using a single sensor has limitations due to the price of expensive sensor. In order to solve this problem, we propose a precise 3D mapping system using low-cost sensor fusion. Generating a point cloud map requires the process of estimating the current position and attitude, and describing the surrounding environment. In this paper, we utilized a commercial visual-inertial odometry sensor to estimate the current position and attitude states. Based on the state value, the 2D LiDAR measurement values describe the surrounding environment to create a point cloud map. To analyze the performance of the proposed algorithm, we compared the performance of the proposed algorithm and the 3D LiDAR-based SLAM (simultaneous localization and mapping) algorithm. As a result, it was confirmed that a precise 3D point cloud map can be generated with the low-cost sensor fusion system proposed in this paper.

• Journal of the Institute of Convergence Signal Processing
• /
• v.13 no.1
• /
• pp.1-5
• /
• 2012

In this study, we constructed a virtual auditory display(VAD) that enables listener to move in a room freely. The VAD system was installed in a soundproof room($4.7m(W){\times}2.8m(D){\times}3.0m(H)$). The system consisted of a personal computer, a sound presentation device, and a three-dimensional ultrasound sensor system. This system acquires listener's location and position from a three-dimension ultrasonic sensor system covering the entire room. Localization was realized by convolving the sound source with head related transfer functions(HRTFs) on personal computer(PC). The calculated result is generated through a LADOMi(Localization Auditory Display with Opened ear-canal for Mixed Reality). The HRTFs used in the experiment were measured for each listener with loudspeakers constantly 1.5m away from the center of the listener' s head in an anechoic room. To evaluate the system performance, we experimented a search task of a sound source position in the condition that the listener is able to move all around the room freely. As a result, the positioning error of presented sound source was within 30cm in average for all listeners.

• Journal of Broadcast Engineering
• /
• v.17 no.5
• /
• pp.827-837
• /
• 2012

As broadcasting environments change rapidly to digital, user requirements for next-generation broadcasting service which surpass current HDTV service become bigger and bigger. The next-generation broadcasting service progress from 2D to 3D, from HD to UHD and from 5.1ch audio to more than 10ch audio for high quality realistic broadcasting service. In this paper, we propose 10.2ch based multichannel audio reproduction system for UHDTV. The 10.2ch-based audio reproduction system add two side loudspeakers to enhance the surround sound localization effect and add two height and one ceiling loudspeakers to enhance the elevation localization effect. To evaluate the proposed system, we used APM(Auditory Process Model) for objective localization test and conducted subjective localization test. As a result of objective/subjective localization test, the proposed system shows the statistically same performance compare with 22.2ch audio system and shows the significantly better performance compared with 5.1ch audio system.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.21 no.2
• /
• pp.294-300
• /
• 2017

This paper proposes a method for 3-D sound source localization (SSL) using region selection and TDOA. 3-D SSL involves the estimation of an azimuth angle and an elevation angle. With the aim of reducing the computation time, we compare signal energies to select one out of three regions. In the selected region, we compute only one TDOA value for the azimuth angle estimation. Also, to estimate the vertical angle, we choose the higher energy signal from the selected region and pair it up with the elevated microphone's signal for TDOA computation and elevation angle estimation. Our experimental results show that the proposed method achieves average error values of $0.778^{\circ}$ in azimuth and $1.296^{\circ}$ in elevation, which is similar to other methods. The method uses one energy comparison and two TDOA computations therefore, the total processing time is reduced.

• Journal of Sensor Science and Technology
• /
• v.12 no.6
• /
• pp.249-257
• /
• 2003

The bio-telemetry technologies, that use the wireless miniaturized telemetry module implanted in the human body and transmits several biomedical signal from inside to outside of the body, have been expected to solve the problem such as the patient's inconvenience and the limit for diagnosis. In the case of transceiver system using the wireless RF transmission method, the method of three-dimensional localization for implantable miniaturized telemetry module is necessary to detect the exact position of disease. A new method for three-dimensional localization using small loop antenna in the implantable miniaturized telemetry module was proposed in this paper. We proposed a method that can accurately determine the position of telemetry module by analyzing the differences in the strength of signal, which is received at each of the small size RF receiver array installed on the body surface.

• Bulletin of the Korean Mathematical Society
• /
• v.29 no.1
• /
• pp.137-143
• /
• 1992

The purpose of this paper is to provide the affirmative solution of the following conjecture due to Davis and Geramita. Conjecture; Let A=R[T] be a polynomial ring in one variable, where R is a regular local ring of dimension d. Then maximal ideals in A are complete intersection. Geramita has proved that the conjecture is true when R is a regular local ring of dimension 2. Whatwadekar has rpoved that conjecture is true when R is a formal power series ring over a field and also when R is a localization of an affine algebra over an infinite perfect field. Nashier also proved that conjecture is true when R is a local ring of D[ $X_{1}$,.., $X_{d-1}$] at the maximal ideal (.pi., $X_{1}$,.., $X_{d-1}$) where (D,(.pi.)) is a discrete valuation ring with infinite residue field. The methods to establish our results are following from Nashier's method. We divide this paper into three sections. In section 1 we state Theorems without proofs which are used in section 2 and 3. In section 2 we prove some lemmas and propositions which are used in proving our results. In section 3 we prove our main theorem.eorem.rem.