Ultrasound Sensor Research Articles

Intelligent Indoor Mobile Robot Navigation Using Stereo Vision

Majority of the existing robot navigation systems, which facilitate the use of laser range finders, sonar sensors or artificial landmarks, has the ability to locate itself in an unknown environment and then build a map of the corresponding environment. Stereo vision, while still being a rapidly developing technique in the field of autonomous mobile robots, are currently less preferable due to its high implementation cost. This paper aims at describing an experimental approach for the building of a stereo vision system that helps the robots to avoid obstacles and navigate through indoor environments and at the same time remaining very much cost effective. This paper discusses the fusion techniques of stereo vision and ultrasound sensors which helps in the successful navigation through different types of complex environments. The data from the sensor enables the robot to create the two dimensional topological map of unknown environments and stereo vision systems models the three dimension model of the same environment.

An analysis of issues in biometric finger identification

A Person's identity is an essential factor in this vastly connected society. Biometric Finger has wide acceptance as a genuine method for determining an individuals identity. Biometric Finger authentication is reliable, since physical characteristics in humans are difficult to forge, harder to change or make copies. Biometric fingerprinting is one of the most popular and legally accepted biometrics used in person identification. Finger print authentication applications include Computer Applications, Network Access, Data Protection, Transaction Security, and Web Security. E-commerce and E-governments can carry out strong authentication rules. This paper analyzes issues related to Fingerprint identification to suggest viable alternatives. Keywords: Fingerprint Identification, Optical Sensors, Ultrasound Sensors, Issues in Finger Print Identification.

Acoustic detection of micro-cracks in small electronic devices

We demonstrate the feasibility of in-situ acoustic detection of micro-cracks in small electronic devices. Applying precisely controlled damage to test vehicles using a nanoindenter, we record brittle fracture of thin layers by means of an ultra-sound piezo sensor, which is able to detect micro-cracks in the moment they emerge. This robustness test does not require further preparation effort that may induce additional stress to a sample or modify it physically, inhibiting unambiguous failure analysis. With regard to its applicability and limitations, we put acoustic emission into context with standard ex-situ experimental procedures for crack characterization in micro-electronic structures.

Design of Reverse Sensor Based on Solar Power

This paper introduced a reverse sensor system based on microprocessor and solar power, and the system is composed of ultrasound sensor, controller of reception, and alarm apparatus. The design of hardware and software of reverse sensor system were also declared in details. The results showed that the reverse sensor system could remind the drivers timely in a way of voice and graph. The reverse sensor system erased the potential problems of back up, and improved the security of drive, which had a high practical value. The power supply of the system was obtained from solar power, and the loadings of vehicle power had been relieved. The complexity and harm of install sensor was refrained.

Precision analysis of single‐element ultrasound sensor for kinematic analysis of knee joints

Measuring the relative motion of the femur and tibia in a knee joint currently requires tantalum beads to be implanted into the bones. These beads appear as high-intensity features in radiographs and can be used for precise kinematic measurements. This procedure imposes a strong coupling between accuracy and invasiveness. Advances in ultrasound (US) sensor technology and the availability of micro-drives mean that it is now possible to construct a small and lightweight US sensor which can be placed on the skin above the tibia and femur. Such a sensor could determine the relative movement of the underlying bone with respect to the sensor. This would then allow the position of the femur and tibia to be measured more accurately than with an optical tracking system that does not take into account the movement of the marker with respect to the bone. For satisfactory performance, the precision of the US sensor should be in the order of 1 mm or less. The experimental results prove that this sub-millimetre precision is achievable.

VISUAL AID SYSTEM BASED ON IMAGE MATCHING AND ULTRASOUND SENSOR PRINCIPLES FOR BLIND PERSONS

Navigation systems have been used for quite a long to support human perception of surrounding environment beyond reach of eyes. The same concept has also been applied to aid the people who are limited with the vision. Many electronics gadgets are developed to improve the vision perception of blind people. The electronic devices available for the aid of blinds are often complex, needs training sessions and come at much higher cost. This research aims at finding a reliable and easy to implement solution for visually challenged persons at a very small cost. This paper is an effort to report a comprehensive method to design, characterize and test electronics system based on image matching, radar and ultrasound sensor principles for the aid of blind persons. The simulation results showed good accuracy for identifying objects. Simulations were carried out in MATLAB and images of test objects were acquired by using NI-LabVIEW platform. The main objectives were to acquire an image of obstacle, identify it, measure a distance from current location and finally convert text into synthesized voice. Finding is expected to be supportive to the vision affected people.

In-body ultrasound image processing for cardiovascular interventions: A review

In this paper we have surveyed the recent developments in the area of in-body ultrasound imaging for cardiovascular interventions. With miniaturized ultrasound sensors integrated at the tip of the instruments (catheters, needles, endoscopes), the local anatomical sites can be imaged with high accuracy. We have covered the applications of TEE (Transesophageal echocardiography), ICE (intracardiac echocardiography) and IVUS (intravascular ultrasound) and the newly emerging therapy monitoring ultrasound. We particularly focus on advanced signal/image processing technologies and related topics such as tissue characterization, image segmentation, device tracking and multi-modality registration. In the context of in-body imaging, we are faced with more challenges than with the traditional external ultrasound imaging, particularly due to the cardiac dynamics. We need to strive for new solutions that provide more consistent, reliable and accurate analysis results for better clinical decision support.

A fast acoustic field mapping approach based on fabry–perot sensor with high‐speed camera

AbstractA Fabry–Perot (FP) interferometer‐based ultrasound sensor provides an inherently broadband response and excellent detection sensitivity compared to piezoelectric zirconate titanate (PZT) or polyvinylidene difluoride (PVDF) transducers. It is therefore expected to be used for medical ultrasound imaging and photoacoustic imaging. However, at present, mapping acoustic fields takes much time for scanning, which hinders real‐time measurement. We propose a new approach that utilizes a high‐speed camera (HSC) to map acoustic fields without mechanical scanning and to sample signals of acoustic waves with the shutter of the HSC. Experimental results indicate that acoustic field at the focus of a pulsed 1‐MHz PZT ultrasound transducer can be detected and mapped by using the FP sensor with the HSC. By improving the uniformity of the FP sensor and the exposure time, the frame rate of HSC can be further developed, and this approach should be able to provide a fast acoustic field mapping for high‐resolution biomedical photoacoustic and other ultrasonic imaging. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Wearable Virtual White Cane: Assistive Technology for Navigating the Visually Impaired1

Wearable Virtual White Cane: Assistive Technology for Navigating the Visually Impaired1

Characterization of the spatio-temporal response of optical fiber sensors to incident spherical waves.

In this study a theoretical framework for calculating the acoustic response of optical fiber-based ultrasound sensors is presented. The acoustic response is evaluated for optical fibers with several layers of coating assuming a harmonic point source with arbitrary position and frequency. First, the fiber is acoustically modeled by a layered cylinder on which spherical waves are impinged. The scattering of the acoustic waves is calculated analytically and used to find the normal components of the strains on the fiber axis. Then, a strain-optic model is used to calculate the phase shift experienced by the guided mode in the fiber owing to the induced strains. The framework is showcased for a silica fiber with two layers of coating for frequencies in the megahertz regime, commonly used in medical imaging applications. The theoretical results are compared to experimental data obtained with a sensing element based on a pi-phase-shifted fiber Bragg grating and with photoacoustically generated ultrasonic signals.

A Measurement System to Realize 3-D Carotid Occlusion Measurement From 2-D Conventional Ultrasonography

A novel measurement system for the 3-D reconstruction of occlusions of the carotid artery is presented. The proposed system can be added onto a conventional diagnostic ultrasonographic system, so that it can be considered as an upgrade for preexisting equipments. It retrieves information from a set of ordinary 2-D ultrasound images and spatial sensors in order to build a 3-D representation of the vessel and of a possible occlusion and to extract measurements of important medical parameters from them. The geometrical modeling of carotid is dealt with. This paper is also concerned with a metrological characterization of the measurement procedure, including the development of a model for the estimation of the uncertainty according to international standards. Experimental results are also reported and discussed.

Tunable enhancement of the acoustic radiation pressure acting on a rigid wall via attaching a metamaterial slab

We demonstrate that the acoustic radiation pressure acting on a rigid wall can be remarkably enhanced by introducing a supplementary metamaterial slab. The dramatic effect stems from the resonant excitation of the acoustic field sandwiched between the rigid wall and the metamaterial slab. Simple formulae for both the enhancement factor and the resonant wavelength are derived analytically, which coincide well with numerical results and exhibit excellent tunability via flexibly tailoring the metamaterials. The acoustic radiation pressure with such tunable magnification could be potentially useful, such as in designing ultrasound instruments and sensors.

Embedded ultrasound sensor in a silicon-on-insulator photonic platform

A miniaturized ultrasound sensor is demonstrated in a silicon-on-insulator platform. The sensor is based on a π-phase-shifted Bragg grating formed by waveguide corrugation. Ultrasound detection is performed by monitoring shifts in the resonance frequency of the grating using pulse interferometry. The device is characterized by measuring its response to a wideband acoustic point source generated using the optoacoustic effect. Experimental results show that the sensor's response is dominated by the formation of surface acoustic waves.

Design and Development of Ultrasound-based Wheelchair

A wheelchair is a most commonly used machine in hospitals for patients, mainly those patients who cannot move or walk or who work with great difficulty. A patient on wheelchair has to depend on another person required to control the motion and direction of the wheelchair to avoid obstacles on their path since the patient is not in a condition to control the wheelchair himself. This makes the patient on the wheelchair dependant.1 The prototype of ultrasound-based wheelchair allows patient on the wheelchair to be self-dependant and the wheelchair itself controls the motion by avoiding obstacles in its path. This wheelchair is mainly designed for handicapped people (blind, limp patients mainly) for their domestic purposes. Ultrasoundbased wheelchair avoids obstacles on its path using ultrasound sensors.2 Once an obstacle is detected, the microcontroller gives signal to the motors of the wheel to perform appropriate actions as per the developed algorithm. The designed prototype causes no inconvenience to the patient and allows patient to move within the house or a specified hospital environment. The design cost of ultrasound-based wheelchair prototype is 7000.

A Surrounding World Knowledge Acquiring by Using a Low-cost Ultrasound Sensors

This article describes a bio-inspired method of identify the type of obstacles which could appear e.g. on the MAV's (Micro Air Vehicles) way. The method is based on measurements made by a low-cost ultrasonic sensor. This kind of sensors are widely used for a distance measurement. The bio-inspired method used by ultrasound sensors uses echo of ultrasound signal to collect the knowledge about the surrounding world. Bats, which use ultrasonic waves to navigate in the dark, were our source of inspiration. In our research we are focusing on the off-the-shelf sensors because of their wide availability. We have shown that we can determine not only the distance but also we can get the basic information about the surrounding space by using the measurement obtained from a simple ultrasonic sensor. Three types of obstacles (smooth surface, rugged or uneven surface, a multifaceted space) and distant space beyond the reach of measurement have been distinguished. All prepared obstacles have been identified properly in our experimental research. Additionally the proposed method can better determine the distance from the nonsmooth surface. A classic method for measuring such obstacles, for which a standard deviation is calculated may not be sufficiently credible due to too large error. In such situation, our analysis allows the use of distance measurement with much more confidence. Our method has been developed in order to support MAV navigation system based on distance measurements made by ultrasonic sensor.

Using existing network infrastructure to estimate building occupancy and control plugged-in devices in user workspaces

Buildings are a major consumer of energy. We believe that energy can be saved with the notion of implicit occupancy sensing where existing IT infrastructure can be used to replace and/or supplement explicit dedicated sensors to determine building occupancy and drive building operation. Implicit sensing has the promise to be both lower in cost than explicit sensing based on PIR and ultrasound sensors and to offer additional useful data about the occupants of a building. Our implicit sensing methods are largely based on monitoring IP and MAC addresses in Wi-Fi access points and in routers, and then correlating these addresses to the occupancy of a floor, area, or room of a building. We experimentally evaluate the feasibility of this dual-use of IT infrastructure. We demonstrate an application of implicit sensing to sense the pending occupancy of a user workspace and automatically control the plugged-in devices in the workspace.

Rao-Blackwellized Particle Smoothing for Occupancy-Grid Based SLAM Using Low-Cost Sensors

We approach the simultaneous localization and mapping problem by using an ultrasound sensor and wheel encoders on a mobile robot. The measurements are modeled to yield a conditionally linear model for all the map states. Moreover, we implement a Rao-Blackwellized particle smoother (RBPS) for jointly estimating the position of the robot and the map. The method is applied and successfully verified by experiments on a small Lego robot where ground truth was obtained by the use of a VICON real-time positioning system. The results show that the RBPS contributes with more robust estimates at the cost of computational complexity and memory usage.

Evaluating ultrasound signals of carbon steel fatigue testing using signal analysis approaches

The application of ultrasound techniques to monitor the condition of structures is becoming more prominent because these techniques can detect the early symptoms of defects such as cracks and other defects. The early detection of defects is of vital importance to avoid major failures with catastrophic consequences. An assessment of an ultrasound technique was used to investigate fatigue damage behaviour. Fatigue tests were performed according to the ASTM E466-96 standard with the attachment of an ultrasound sensor to the test specimen. AISI 1045 carbon steel was used due to its wide application in the automotive industry. A fatigue test was performed under constant loading stress at a sampling frequency of 8 Hz. Two sets of data acquisition systems were used to collect the fatigue strain signals and ultrasound signals. All of the signals were edited and analysed using a signal processing approach. Two methods were used to evaluate the signals, the integrated Kurtosis-based algorithm for z-filter technique (I-kaz) and the short-time Fourier transform (STFT). The fatigue damage behaviour was observed from the initial stage until the last stage of the fatigue test. The results of the I-kaz coefficient and the STFT spectrum were used to explain and describe the behaviour of the fatigue damage. I-kaz coefficients were ranged from 60 to 61 for strain signals and ranged from 5 to 76 for ultrasound signals. I-kaz values tend to be high at failure point due to high amplitude of respective signals. STFT spectrogram displays the colour intensity which represents the damage severity of the strain signals. I-kaz technique is found very useful and capable in assessing both stationary and non-stationary signals while STFT technique is suitable only for non-stationary signals by displaying its spectrogram.

Accuracy assessment of Tri-plane B-mode ultrasound for non-invasive 3D kinematic analysis of knee joints

BackgroundCurrently the clinical standard for measuring the motion of the bones in knee joints with sufficient precision involves implanting tantalum beads into the bones. These beads appear as high intensity features in radiographs and can be used for precise kinematic measurements. This procedure imposes a strong coupling between accuracy and invasiveness. In this paper, a tri-plane B-mode ultrasound (US) based non-invasive approach is proposed for use in kinematic analysis of knee joints in 3D space.MethodsThe 3D analysis is performed using image processing procedures on the 2D US slices. The novelty of the proposed procedure and its applicability to the unconstrained 3D kinematic analysis of knee joints is outlined. An error analysis for establishing the method’s feasibility is included for different artificial compositions of a knee joint phantom. Some in-vivo and in-vitro scans are presented to demonstrate that US scans reveal enough anatomical details, which further supports the experimental setup used using knee bone phantoms.ResultsThe error between the displacements measured by the registration of the US image slices and the true displacements of the respective slices measured using the precision mechanical stages on the experimental apparatus is evaluated for translation and rotation in two simulated environments. The mean and standard deviation of errors are shown in tabular form. This method provides an average measurement precision of less than 0.1 mm and 0.1 degrees, respectively.ConclusionIn this paper, we have presented a novel non-invasive approach to measuring the motion of the bones in a knee using tri-plane B-mode ultrasound and image registration. In our study, the image registration method determines the position of bony landmarks relative to a B-mode ultrasound sensor array with sub-pixel accuracy. The advantages of our proposed system over previous techniques are that it is non-invasive, does not require the use of ionizing radiation and can be used conveniently if miniaturized.

Wireless Gesture Controlled Systems

Present day scenario is tending towards the elimination of Human Interface device to Computers and other devices. Gaming systems are going towards complete elimination of controllers and moving towards use of cameras and Ultrasound sensors to detect the movements of gamers, which act as inputs rather than the signals sent by controllers. Similar systems have also been used to help the blind and the Paralympic people. This proposed system helps do the same. It translates the gestures and movement of the wrist and fingers to control the mouse of a computer or to interface the same to any device granting wireless control to devices based only on these movements. This can be applied to control wheelchairs for the disabled or a robotic arm for bomb diffusion. The main advantage of this project is that it uses sensors to track all the movements of an arm thereby giving the user freedom to be anywhere within the wireless range to control the system, unlike in systems based on camera to recognize the movements which restrict the user to face the camera at a particular angle. The system currently proposed in the paper is for mouse control and the extent of expansion is limited only by the hardware interfaced to the receiver end.