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In recent years, microphone array signal processing has been actively studied in the field of engineering. In consideration of our hope that children's interest in this technology will contribute to the future development of science and technology, we have developed the KIKIWAKE system with a microphone array and conducted the Prince Shotoku Game to promote children's interest. Then, we confirmed the effectiveness of the system through interviews. [ABSTRACT FROM PUBLISHER]

The authors are developing a novel learning support system "Human SUGOROKU" by integration of ultrasonic sensors and Kinect sensors. The system is a relocatable large scale digital board game that human-players as its piece move on squares. To realize the system, we measure players locations and gestures identifying players, by integrating output information from both sensors. This paper explains overview of the system and proposes a method to reduce installation time. That length of installation time is one of the most serious problems when we relocate the system. Most part of the time is spent to unify sensors' coordinate systems. Usually, as each sensor has own coordinate system, we can't use sensors' output directly without unifying their coordinate systems. In order to unify sensors' coordinate systems, we need accurate positioning of the sensors, but accurate positioning manually is difficult and takes much time. The proposed method is a positioning-free convenient unifying method for different kinds of multiple sensors by using dedicated instrument. We conduct an experiment to evaluate the proposed method, and confirm that the method can reduce installation time for the system. [ABSTRACT FROM PUBLISHER]

Recently, the authors described a new algorithm for ultrasonic Doppler imaging and velocity estimation using log-step multicarrier signals. The algorithm achieved a velocity estimation precision that was some 20 times better than that using an existing method, but the problem of estimation deficiency in low-SNR conditions remained. In this work, we improve the availability of the algorithm in low-SNR conditions by utilizing the systematic temporal shift of the log-step multicarrier signals, which expresses approximately the amount of Doppler shift in the sensed signal. A computer simulation shows high availability for the algorithm, even for SNR values below −10 dB. [ABSTRACT FROM PUBLISHER]

We propose a novel technique for 3D localization that integrates a single camera and ultrasound. We use the Extended Phase Accordance Method and the ultrasound to measure accurately the distance to a moving target and we use the camera to identify the target's 2D position on the image plane. A prototype system consists of a transmitter unit mounting one ultrasound transmitter and three infrared LEDs around it, and a receiver unit with one inexpensive camera and one ultrasound receiver. We implemented these units in a lightweight and compact way (receiver unit size: 55 mm × 44 mm), to make the system robust against the no-line-of-sight problems that frequently occur in trilateration or multicamera-based systems. Experimental results show that the RMSEs of the proposed system are 1.20 mm and 1.66 mm for static and mobile (velocity: 1.0 m/s) targets, respectively. These indicate that the performance of the system is comparable with that of high-end systems. [ABSTRACT FROM PUBLISHER]

This paper presents a novel framework for developing automatic animation systems, which accept a 3D model that is created at runtime. Previous systems cannot deal with such a 3D model because it needs to be prepared by a manual process (rigging) that may not be suitable for nonprofessional users. The proposed framework solves this problem by employing an automatic rigging algorithm. Our algorithm can generate an animation skeleton for a given 3D model automatically, including the anatomical meaning of each joint. The relationship between motion data and this animation skeleton is created by identifying the corresponding joints in the motion data and the skeleton. The motion data for each joint is transferred automatically to the 3D model that has been rigged via our automatic rigging algorithm. Because all processes can be completed without any user intervention, an animation system for nonprofessional users is therefore available. We also discuss several motion editing techniques that can be used to generate new motion data without complex processing. [ABSTRACT FROM PUBLISHER]

In an acoustic imaging system, ultrasonic transmitters always have uneven signal strength in the imaging space. Phase changes also occur depending on the distance and direction. In this paper, a new approach to decrease the effect of a transmitter's radiation pattern in acoustic imaging is proposed. We compensated for the transmitter's radiation pattern and reconstructed acoustic images using the Synthetic Transmit Aperture imaging technique. The compensation was based on the radiation pattern obtained from real measurements and using a Wiener filter. The purpose of the work was to compensate for a nonideal radiation pattern of the ultrasonic transmitter for both phase and amplitude aspects. An airborne imaging experiment was conducted using a two-dimensional (2D) receiver array and a 2D transmitter array to verify the effectiveness of our proposed method. The results showed an improvement in the vertical angular resolution of reconstructed three-dimensional images. [ABSTRACT FROM PUBLISHER]

This paper describes a new ranging technique using optical signals. The proposed technique is called LT-PAM (Long-Term Phase Accordance Method), and it has been extended from our own ranging technique called Phase Accordance Method (PAM). LT-PAM transmits multiple sync patterns composed of two sinusoidal waves with different frequencies. Unlike chirp modulation techniques, LT-PAM transmits the two waves simultaneously and thus enables the shortening of measurement time. We have conducted experiments using two types of light sources, collimated and diffused light. The experimental results indicated that the proposed method showed a moderate level of accuracy by adjusting the measurement time. For example, LT-PAM using a light emitting diode transmitting multiple sync patterns lasting 4 ms achieved 19.5 mm standard deviation in a measurement ranging 1500 mm. We also describe the theoretical analyses related to the proposed technique and discuss possible improvements by comparing theoretical and experimental results. [ABSTRACT FROM PUBLISHER]

In this paper, we introduce a puppet interface for the development of an intuitive animation system. Our puppet interface does not require any special devices and any type of puppet can be used. The puppet interface is developed by attaching ten visible markers onto a puppet. The user can manipulate the pose of the puppet interface to produce the desired motion in front of a camera. The puppet's joint angle information is captured by the camera and used to retrieve a suitable motion from a motion database. The retrieved motion data is transferred to a 3D character model to generate an animation. To avoid the occlusion problem, we propose an algorithm that estimates the joint angle by determining the position and rotation of markers adjacent to the occluded marker. Experiments confirmed that our proposed algorithm can generate correct results, although some occluded markers remained. [ABSTRACT FROM PUBLISHER]

In this paper, we describe a novel technique for detecting raindrops using in-vehicle camera images. The appearance of raindrops on a car windshield can depend on their background, so it is often difficult to detect them using conventional template matching methods, which are based on image features. Initially, we extract potential raindrop regions from images, before generating a rendered background image using a physical raindrop model based on the refraction of light rays. This rendered image is then used to identify true raindrops based on their similarity to the true background image. We propose a new model that approximates a raindrop shape as a spheroid section. This method can represent different raindrop shapes more adaptively and flexibly than conventional models, which approximate raindrops as a section of a sphere. We also extend the Maximally Stable External Regions algorithm to extract candidate raindrops and we identify three measures of image similarity using a Support Vector Machine algorithm. We conducted experiments that confirmed the effectiveness of the proposed technique. [ABSTRACT FROM PUBLISHER]

We have so far developed and evaluated a 3D ultrasonic localization system using the Extended Phase Accordance Method (EPAM) [3]. The method allows us to measure a 3D position of a transmitter by using a single compact receiver unit whose baseline is 76.2 mm and shows the satisfactory level of accuracy (13mm standard deviation in a static situation) for indoor positioning. However, we found that ultrasonic microphones showed different phase characteristics to different wave incident angles. Since EPAM uses the phase information of received signals for 3D localization, these phase characteristics induce a ranging error and therefore a transmitter is not correctly localized. To compensate these localization errors, we have conducted experiments and clarified phase characteristics of microphones. [ABSTRACT FROM PUBLISHER]

We propose a new technique for acoustic imaging that employs the back projection algorithm to process signals from a static ultrasonic microphone array. To obtain a projection data of a target, we integrate the time distribution of received signal powers gained by pulse compression with the Radon transform of a sound field in the spherical polar coordinates. In case of 2D imaging, the proposed method is expected to improve angular resolution [1]. In this paper we describe the principle of the proposed algorithm for 2D imaging, and explained how it was extended to 3D imaging. This proposed 3D imaging method allow us to rapidly obtain imaging results of areas of interest. We conducted a computer simulation to verify the performance of the proposed algorithm. In our future works, we plan to conduct experiments in real environments and deeply investigate the theoretical aspects of the proposed method. [ABSTRACT FROM PUBLISHER]

A new approach for 3D acoustic imaging using a 2D receiver array and a 2D transmitter array is proposed. The proposed method utilizes synthetic transmit aperture (STA) technique and a power radiation pattern of a transmitter. The STA technique has been used in acoustic imaging for reconstructing high quality images by using a few transmission events. However, it assumes that a transmitter produces equal energy over the imaging area. This leads to a deterioration of images especially when a 2D transmitter array is used. The proposed method integrates a power radiation pattern of a transmitter into STA technique to compensate the non-ideal radiation of the transmitter. The reconstructed images from the proposed method show the improvement in terms of image quality. [ABSTRACT FROM PUBLISHER]

In ultrasonic imaging, the Doppler effect, which is caused by the movement of the target, causes a frequency shift on the reflected sound, and results in object detection failure. [ABSTRACT FROM PUBLISHER]