Omnidirectional System Research Articles

Moving object detection by mobile Stereo Omni-directional System (SOS) using spherical depth image

Moving object detection with a mobile image sensor is an important task for mobile surveillance systems running in real environments. In this paper, we propose a novel method to effectively solve this problem by using a Stereo Omni-directional System (SOS), which can obtain both color and depth images of the environment in real time with a complete spherical field of view. Taking advantage of the SOS that the frame-out problem never occurs, we develop a method to detect the regions of moving objects stably under arbitrary movement and pose change of the SOS, by using the spherical depth image sequence obtained by the SOS. The method first predicts the depth image for the current time from that obtained at the previous time and the ego-motion of the SOS, and then detects moving objects by comparing the predicted depth image with the actual one obtained at the current time.

Detection of moving object by mobile stereo omnidirectional system (SOS)

AbstractMoving object detection with a mobile image sensor is an important task in robotics and computer vision, when considering the practical use of robotics in human environments. In this paper, we propose a robust method that detects moving objects in the environment using the omnidirectional depth information obtained by a mobile Stereo Omnidirectional System (SOS). In order to detect only the moving objects within the depth image that are obtained by a sensor in motion, we first estimate the ego‐motion of the sensor, and generate a predicted depth image for the current time from the depth obtained at the previous time by only considering the ego‐motion of the sensor. Then the predicted depth image is compared with the actual one obtained at the current time, and the inconsistent regions are detected as moving objects. When the sensor moves, occlusions will occur in the scene and they will cause false detections. However, these false detections can be suppressed by estimating the occlusion regions using the ego‐motion parameters of the sensor and the jump edges in the depth image. The effectiveness of the method is shown with experimental results for a real environment. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(3): 29–38, 2005; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/eej.20155

1P1-N-126 全方向移動機構を持つパッシブ型歩行支援機における操作性の向上(医療福祉ロボティクス・メカトロニクス1,生活を支援するロボメカ技術のメガインテグレーション)

1P1-N-126 全方向移動機構を持つパッシブ型歩行支援機における操作性の向上(医療福祉ロボティクス・メカトロニクス1,生活を支援するロボメカ技術のメガインテグレーション)

1P1-N-127 User Adaptive Loose Guide Method for an Omnidirectional Passive Walking Aid System(Medical and Welfare Robotics and Mechatronics 1,Mega-Integration in Robotics and Mechatronics to Assist Our Daily Lives)

1P1-N-127 User Adaptive Loose Guide Method for an Omnidirectional Passive Walking Aid System(Medical and Welfare Robotics and Mechatronics 1,Mega-Integration in Robotics and Mechatronics to Assist Our Daily Lives)

Development of Running Environment Risk Detection System for Electric Wheelchair based on Stereo Omni-directional System

Development of Running Environment Risk Detection System for Electric Wheelchair based on Stereo Omni-directional System

Design and Development of a Comprehensive Omni directional Soccer Player Robot

Omni directional mobile robots have been popularly employed in several applications especially in soccer player robots considered in Robocup competitions. However, omni directional navigation system, omni-vision system and omni-kick mechanism in such soccer player robots have not ever been combined. This situation brings the idea of a robot with no head direction into existence, i.e. a comprehensive omni directional soccer player robot. Such a robot can respond more quickly and it would be capable for more sophisticated behaviors such as ball passing or goal keeping. This paper has tried to focus on description of areas such as omni directional mechanisms, mechanical structure, control, optimized odometry system, omni-vision sensor for self localization and other subjects related to soccer player robot's software.

Detection of Moving Object by Mobile Stereo Omni-directional System (SOS)

Moving object detection with a mobile image sensor is an important task in robotics and computer vision, when considering the practical use of robots in human environments. In this paper, we propose a robust method that detects moving objects in the environment using the omni-directional depth information obtained by a mobile Stereo Omni-directional System (SOS). In order to detect only the moving objects within the depth image that are obtained by a sensor in motion, we first estimate the ego-motion of the sensor, and generate a predicted depth image for the current time from the depth obtained at the previous time by only considering the ego-motion of the sensor. Then the predicted depth image is compared with the actual one obtained at the current time, and the inconsistent regions are detected as moving objects. When the senor moves, occlusions will occur in the scene and they will cause false detections. However, these false detections can be suppressed by estimating the occlusion regions using the ego-motion parameters of the sensor and the jump edges in the depth image. The effectiveness of the method is shown with the experiment results on a real environment.

Neural Networks for Autonomous Path-Following with an Omnidirectional Image Sensor

This paper presents a path-following system implemented with two different types of neural networks, that enables an autonomous mobile robot to return along a previously learned path in a dynamic environment. The path-following is based on data provided by an omnidirectional conical visual system, derived from the COPIS sensor, but with different optical reflective properties. The system uses optical and software processing and a neural network to learn the path, described as a sequence of selected points. In the navigation phase it drives the robot along this learned path. Interesting results have been achieved using low cost equipment. Test and results are presented.

３次元映像情報メディア技術 全方向ステレオシステム（ＳＯＳ）のキャリブレーション手法

We have developed a system called the Stereo Omnidirectional System (SOS). The stereo units, which are composed of three cameras, in this system are arranged on each plane of regular icosahedrons. This system can acquire all directional color and stereo pair images, in real time. However calibrating this multi-camera system, which acquires images in different directions from the center of the system, is difficult because simultaneously acquiring images of common regions from multiple cameras is not possible. We described a hybrid calibration method in which the translation parameters use the system design parameters and the rotational parameters are obtained from the images. These adjustments are made because of the difficulty in accurately, obtaining the translation and rotational parameters from the images so that they can be compared. We also described how the color registration method uses common region images acquired from the system.

実環境センシングのための全方向ステレオシステム (SOS)

実環境センシングのための全方向ステレオシステム (SOS)

Enhancement of reflected waves in single-hole polarimetric borehole radar measurement

A polarimetric approach is presented to extract information of reflected waves that is masked by the transmitter-receiver directly coupled wave in a single-hole borehole radar measurement. Radar polarimetry theory is expanded to an omnidirectional radar system with electric and magnetic dipoles arranged on the same axis. First, we formulate the transfer functions directly coupled between the antennas for cross-hole and single-hole arrangements in copolarized channels. We found that the theoretical scattering matrices of the direct-wave coupling is identical to the scattering matrix from a dihedral corner reflector. Second, we also consider signals in polarimetric channel of a wave reflected from a plane scatter in single-hole arrangements. As advanced reflection borehole radar measurement, we demonstrate a technique for both reduction of the directly coupled wave and enhancement of the reflected waves from a plane fracture with measured data in dipole-dipole and slot-slot antenna combinations. For quantitative determination of the scattering matrix, we use a technique to compensate the antenna transfer functions by the time derivative of the directly coupled signals in single-hole measurement. Also, we propose a technique to reduce the directly coupled component by adding vertical (VV) and horizontal (HH) signals and we showed that the directly coupled wave is effectively reduced and reflected waves are enhanced with experimental data. Finally, we show that this technique is more useful for near-range reflector detection than a conventional subtraction technique with moving average of the measured waveforms.

Omni-directional loudspeaker system

A loudspeaker system includes a flexible compressible tube having a woofer mounted at one end with its cone directed outward, and a vented baffle mounted at the other end. A first sound dispersion element is mounted with its apex facing the cone of the woofer and a midrange speaker is mounted in the base of the dispersion element with its cone facing away from the tube. A second sound dispersion element is mounted with its apex facing the cone of the midrange speaker, and at least one tweeter is mounted on the base of the second sound dispersion element with its cone facing away from the tube. According to one embodiment, a plurality of tweeters are mounted in an enclosure mounted on the base of the second dispersion element. According to another embodiment, a single tweeter is mounted in the base of the second dispersion element and a third dispersion element is mounted with its apex facing the cone of the tweeter. According to a preferred embodiment of the invention, a pair of tubes are coupled to each other at their baffles to form a stereo speaker system. A fabric sleeve having a graphic display which may include an advertisement fits over the tubes. In order to enhance the aesthetic appearance of the speaker system and to protect the speakers from the environment, a fabric covering is optionally provided over the speakers and dispersion elements.

35 ħ two-stage SQUID system for gravity wave detection

We have designed, built and tested a two-stage SQUID measuring system which is primarily intended for use in a 50 mK omnidirectional gravity wave detection system. We fabricated three Nb-Al/AlO/sub x/-Nb trilayer SQUIDs on a single chip: there is one sensor SQUID and two readout SQUIDs which amplify the output of the sensor SQUID. At a temperature of 90 mK, we measured an intrinsic energy sensitivity of the sensor SQUID of /spl epsi//sub v/=S/sub /spl Phi///(2L)=35/spl planck/ at 1 kHz, of which 24/spl planck/ is white noise and 11/spl planck/ is 1/f noise.

Omnidirectional speaker system

Omnidirectional speaker system

Omnidirectional speaker system

An omnidirectional speaker system includes woofer and tweeter speakers mounted in a concave, curved upper fabricated of a relatively hard shell exterior and a foam interior, preferably plastic. Beneath the upper housing is a base, including a generally conical phase compensation plug which disperses the sound waves equally in all directions through a circumferential aperture between the upper housing and base. In a preferred embodiment, the cross-sectional shape of the upper housing is parabolic and the cross-sectional shape of the phase compensation plug is hyperbolic.

Correlated co‐channel log‐normal interferers in cellular radio

AbstractThe probability of co‐channel interference (PCI) in cellular radio systems is analyzed assuming that the desired signal and the co‐channel interferers are correlated in a log‐normal shadowing environment. The correlation between the signals in a log‐normal shadowing environment reduces the PCI and hence allows operation with shorter frequency reuse distances and smaller cluster sizes. Compared with omnidirectional systems, the cells employing directional antennas can operate with shorter frequency reuse distances and hence provide better usage of the frequency spectrum.

Hybrid solar heating and ventilation: The monymusk housing project

The paper reports on recent research at Aberdeen University to predict, with the aid of transient systems simulation, the performance of a new hybrid solar sheltered housing development in Monymusk, Scotland. The proposed dwelling units embody several unique design concepts, including an entirely traditional exterior appearance indistinguishable from the local vernacular, a new optimised omni-directional solar roof collector system which combines both heating and ventilation functions, and the ability to automatically switch between a range of heating and/or ventilation modes when required.

Effects of sectorization on the spectrum efficiency of cellular radio systems

The effects of sectorization on the spectrum efficiency of a cellular system at different values of cell radius are studied. For a given cluster size, sectorization provides a higher signal-to-interference (S/I) ratio but reduces the spectrum efficiency of the system. It is demonstrated that it is possible to achieve higher spectrum efficiency by reducing the cluster size in a sectorized system without lowering the S/I ratio below the minimum requirement. In this respect, under both shadowing and nonshadowing conditions, there is an increase of spectrum efficiency of the sectorized systems over the omnidirectional system. The consistent gain in efficiency occurs when the cell radius exceeds a certain value depending on the traffic density in the cell.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Effects of correlated shadowing signals on channel reuse in mobile radio systems

The authors present a study to evaluate the cochannel interference probability for the desired and interference signals which are correlated due to shadowing. The effects of correlation on the normalized reuse distance are investigated. A generalized expression for the cochannel interference probability is derived by combining uncorrelated (fast) Rayleigh fading and correlated (slow) log-normal signals. The cochannel interference probability for sectorized cell layouts is compared with the lower bound of cochannel interference probability for omnidirectional antenna systems. It is found that omnidirectional cell layouts cause the highest level of cochannel interference probability. An omnidirectional system requires a higher cluster size than a directional system to maintain acceptable cochannel interference.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Calibration Of An Omnidirectional Vision Navigation System Using An Industrial Robot

The characteristics of an omnidirectional vision navigation system were studied to determine position accuracy for the navigation and path control of a mobile robot. Experiments for calibration and other parameters were performed using an industrial robot to conduct repetitive motions. The accuracy and repeatability of the experimental setup and the alignment between the robot and the sensor provided errors of less than 1 pixel on each axis. Linearity between zenith angle and image location was tested at four different locations. Angular error of less than 1° and radial error of less than 1 pixel were observed at moderate speed variations. The experimental information and the test of coordinated operation of the equipment provide understanding of characteristics as well as insight into the evaluation and improvement of the prototype dynamic omnivision system. The calibration of the sensor is important since the accuracy of navigation influences the accuracy of robot motion. This sensor system is currently being developed for a robot lawn mower; however, wider applications are obvious. The significance of this work is that it adds to the knowledge of the omnivision sensor.