Tadashi Ebihara
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Parameter Determination in Basis Pursuit Denoising via Stein’s Unbiased Risk Estimate for Underwater Acoustic Communication With Orthogonal Signal Division Multiplexing Open
This paper proposes a novel method for determining parameters in underwater acoustic (UWA) communication using orthogonal signal division multiplexing (OSDM) combined with basis pursuit denoising (BPDN). Recent studies revealed that BPDN c…
Enhancing azimuth estimation in low-resolution underwater acoustic lens systems for advanced communication and positioning Open
Here we aimed to enhance azimuth estimation to accurately locate a communication partner’s position by utilizing a low-resolution underwater acoustic lens system for communication. We proposed a method to accurately estimate the direction-…
Detection of free-swimming fish passing through a narrow passage using MHz-band ultrasonic reflected and transmitted waves Open
In this study, we evaluated the validity of detecting free-swimming fish using echoes from the fish, transmitted waves, and backwall echoes propagated through the fish, using a pair of transducers with MHz-band ultrasound in a small, shall…
Measurement of distance and speed between transmitter and receiver using the propagation time of underwater acoustic communication signals with orthogonal signal division multiplexing Open
This paper proposes a procedure for measuring transmitter–receiver (Tx–Rx) distance using acoustic communication signals to realize communication and positioning underwater with the same signal and device. Specifically, we focus on an unde…
Self-Localization Method Using a Single Acoustic Ranging Sensor Based on Impulse Response and Doppler Effect Open
This study aims to realize self-position estimation for indoor robots using only a single acoustic channel. When a single omnidirectional transmitter/receiver is used as an object detection sensor, detected objects are identified on concen…
Sparse Channel Estimation With Global Optimum Solution for Orthogonal Signal Division Multiplexing in Underwater Acoustic Communication Open
This paper proposes sparse channel estimation using basis pursuit denoising (BPDN) with a global optimum solution (GOS) for underwater acoustic (UWA) communication using orthogonal signal division multiplexing (OSDM). To realize reliable U…
Investigation of Characteristics of Underwater Acoustic Channel and Quality of Underwater Acoustic Communication in Line-of-Sight and Non-Line-of-Sight Environments Open
Underwater acoustic (UWA) communication is an essential technology for networking underwater sensors and drones to support maritime activities. However, real-time data transfer among mobile nodes faces technical difficulties due to the sev…
Detection of fish passing through a narrow path using reflected and transmitted ultrasonic waves Open
The properties of echoes and transmitted waves from a fish body in megahertz bands were investigated to construct a fish detection method in a narrow path using a simple measurement structure using a pair of transducers. Experiments were p…
Simultaneous distance measurement and information transmission in mobile environment using digital acoustic communication Open
The purpose of this paper is to examine the feasibility of indoor acoustic positioning by measuring transmission distance and speed while simultaneously transmitting information using digital acoustic communication. The method we propose a…
EXPERIMENTS ON UNDERWATER POSITIONING OF MOBILE OBJECTS IN MULTIPATH ENVIRONMENTS USING SOUND WAVE PROPAGATION TIME GROUPS AND DATABASE MATCHING Open
音波を用いた水中測位における課題の一つとして,浅海域や港湾部における多重反射(マルチパス)環境における欠測の発生や大きな誤差の存在がある.我々は不要な反射波を排除する信号フィルタリング技術を有する新しい「耐マルチパス水中音響測位技術」を構築してきた.この技術は,空間上のある領域に音源が存在する場合,音源から各受波器までの伝搬時間を予め計算機上で求めておき,該遅延時間前後のインパルス応答のみを抽出することで,マルチパス環境でも三角測量に必要な基線長を安定かつ精度良く測定するも…
Attracting Effect of Pinpoint Auditory Glimpse on Digital Signage Open
Advertising signage installed in public spaces is intended to be seen by passersby to increase recognition. However, display blindness often occurs because people either assume that the displayed content is not relevant to them or the disp…
Spatialphonic360: Acoustic Space for Arbitrary Sound Image Presentation Based on Both Ears Tracking Open
Conventional stereophonic sound fixed the sweet spot or limited only the front sound image. Therefore, there is a problem that it cannot cover interactivity, such as the listener's movement or turning around. In this study, we developed an…
Rolling-shutter-sensor-based visible light communication for multi-user long-range communication and positioning Open
We propose a rolling-shutter-sensor-based visible light communication (RS-VLC) system using a cross-screen filter suitable for intelligent transport system (ITS) scenarios. The proposed system uses a cross-screen filter to diffuse the rece…
Indoor self-localization using multipath arrival time measured by a single acoustic ranging sensor Open
The objective of this study is to achieve vehicle self-localization using a single acoustic ranging sensor in a multipath environment. For this purpose, we proposed a measurement method of multiple time-of-flight (ToF) using an acoustic ra…
Design of a hemispherical compound eye lens consisting of a concave meniscus for underwater acoustic communication Open
Multi-user underwater acoustic communication is expected to support efficient and reliable underwater exploration by networking devices in oceans. However, crosstalk occurs when multiple devices emit signals simultaneously. To address this…
EYEDi: Graphical Authentication Scheme of Estimating Your Encodable Distorted Images to Prevent Screenshot Attacks Open
Graphical authentication schemes have the advantage of being more memorable than conventional passwords. Although some image distortion methods have been proposed to prevent the risks of over-the-shoulder attacks (OSAs), these methods cann…
SELF-LOCALIZATION METHOD USING ACOUSTIC REFLECTION FOR INSPECTION ROBOT IN UNDERGROUND ENVIRONMENTS Open
本論文では屋内土木環境においてロボットを導入する際の自己位置推定法について音響反射を用いる手法を提案する．音響センサーは一対の水平無指向性スピーカーと水平無指向性マイクロフォンで構成され，スピーカーから放出した音が壁面で反射しマイクロフォンに到達するまでの時間を計測することで各壁に対する反射経路の距離を計測する．さらに，推定された反射経路の距離，ロボットの車輪に取り付けられたロータリーエンコーダーの回転数，事前に与えられた地図情報を入力とし拡張カルマンフィルタを用いて自己位…
Optimal Modulation Technique for Underwater Visible Light Communication Using Rolling-Shutter Sensor Open
The visible light communication (VLC) technique using a rolling-shutter sensor-based commercial camera has an advantage in that the LED and camera mounted on an underwater device (e.g., drone, sensor) can be effectively used as a transmitt…