Ultrasound Sensor Research Articles

Photoacoustic Imaging of the Breast Using the Twente Photoacoustic Mammoscope: Present Status and Future Perspectives

The Twente photoacoustic mammoscope (PAM) uses pulsed light at 1064 nm to excite PA signals. Detection is using a planar 590-element ultrasound (US) sensor matrix. Image reconstruction uses a delay-and-sum beamforming algorithm. Measurements are performed in the forward mode, with mild compression of the breast against the detector with US coupling gel. We consolidate the most important specifications of the system. Furthermore, we discuss in detail the results of imaging two cases of infiltrating ductal carcinoma and one case of a cyst. We critically discuss the features of the present embodiment and present plans for its improvement.

Capabilities of Ultrasound for Monitoring and Quantitative Analysis of Polyolefin Waste Particles in Magnetic Density Separation (MDS)

A study was conducted into the potential of ultrasound as a qualitative and quantitative tool for the Magnetic Density Separator (MDS), where an ultrasound sensor array will operate from inside the MDS ferrofluid. The desired applications of the ultrasound are monitoring of polyolefin particles in flow during the separation process, and performing throughput measurements and quality inspection. The possibility to adapt off-the-shelf medical imaging technology was investigated with an eye towards the real-time requirements for industrial application. It is shown that a medical imager can be adapted for monitoring the flowing particles at speeds up to 30 cm/s, and the imaging quality can be very good under optimum viewing angle conditions. Ultrasound imaging may also allow for quantitative through-put analysis provided the flowing particles are sufficiently spaced, which puts a limit to the maximum measurable throughput. If viewing conditions are not optimum the medical imager relies on the human operator to improve image quality. This situation is undesired for industrial operation where there may be little or no time for operator intervention. To anticipate these occurrences a second imaging method is proposed that could act in conjunction, which is effective since it is based on a different physical principle. Ultrasound quality inspection is a very different technique, and its feasibility depends first of all on whether different types of polyolefin are acoustically distinctive. Using experiments and 3D acoustic computer modelling to determine wave speed and material attenuation, the potential of ultrasound for polyolefin identification under immersed conditions was investigated. With a calibrated measurement setup it is shown that polyolefins may potentially be classified into acoustically distinctive groups. The possible errors in throughput measurement and quality inspection and the requirements for these techniques to perform under operational MDS conditions are also addressed.

Complex Analysis of Car Shredder Light Fraction

Float fraction of float/sink process of car shredder light fraction was received from RAV (The Netherlands) in the frame of the W2Plastics (http://www.w2plastics.eu/) EU7 project (magnetic sorting and ultrasound sensor technologies for production of high purity secondary polyolefins from waste). The differently coloured plastic waste particles were manually separated and after determining the mass fractions, the particles were analysed by FTIR and Raman spectroscopy. This procedure was repeated also after washing the particles. According to the results the analysed fraction of plastic wastes contained mainly PP and PE, the major large scale contaminants were wood, elastomers and other copolymers. Raman mapping proved to be useful in detecting minor components of polymer waste sample.

Investigation of curing behaviour of melamine/phenolic (MP) thermosets

Commercially available melamine/phenolic (MP) moulding compounds used for manufacturing electro installation parts were investigated by laboratory thermal analysis methods: Dynamic Mechanical Analysis (DMA), Differential Scanning Calorimetry (DSC) and Dielectric Analysis (DEA). The results were compared with on-line measurements in a compression mould using incorporated dielectric and ultrasound sensors. Softening and cross-linking behaviour were analyzed. For on-line process monitoring, only the ultrasound method worked well. The dielectric method was distorted by water formed as a by-product from the poly-condensation reaction.

Pervasive Computing for Automobiles: An Approach to Maximize User Convenience and Safety Using VANETs

Invention of wheel was perhaps the most significant invention in the evolution of mankind. From the earliest carts to the present day automobiles, industry has witnessed dramatic changes and innovations. But even today, automobiles are equipped with mechanical, electrical and electronic devices that are not smart enough to take decisions on behalf of the user. The way mobile computing devices and applications are developed, deployed and used in automobiles today falls short of the potential for pervasive computing. This paper attempts to build a model of an automobile that uses pervasive computing to maximize user convenience and safety. The concept used is that of Vehicular Ad-hoc Networks (VANETs). The major concern in a VANET is to provide reliable and efficient packet delivery mechanism taking into consideration the limited battery back-up of the mobile devices and also the available bandwidth. Moreover, data communication between vehicular mobile devices can minimize head-on collisions by proper auto-break mechanism implementation using Ultra Sound Generators and sensors. The implementation issues are also addressed in this paper. Ultimately, this paper presents ideas that could make driving simpler and safer as compared to the present day.

Method and apparatus for localizing an ultrasound catheter

An imaging system is provided with an ultrasound catheter and a controller coupled to the ultrasound catheter. The catheter includes a localizer sensor configured to generate positional information for the ultrasound catheter, and an imaging ultrasound sensor having a restricted field of view. The controller co-registers images from the imaging ultrasound sensor with positional information from the localizer sensor.

PE-CMOS based C-scan ultrasound for foreign object detection in soft tissue

In this paper, we introduce a C-scan ultrasound prototype and three imaging modalities for the detection of foreign objects inserted in porcine soft tissue. The object materials include bamboo, plastics, glass and aluminum alloys. The images of foreign objects were acquired using the C-scan ultrasound, a portable B-scan ultrasound, film-based radiography, and computerized radiography. The C-scan ultrasound consists of a plane wave transducer, a compound acoustic lens system, and a newly developed ultrasound sensor array based on the complementary metal-oxide semiconductor coated with piezoelectric material (PE-CMOS). The contrast-to-noise ratio (CNR) of the images were analyzed to quantitatively evaluate the detectability using different imaging modalities. The experimental results indicate that the C-scan prototype has better CNR values in 4 out of 7 objects than other modalities. Specifically, the C-scan prototype provides more detail information of the soft tissues without the speckle artifacts that are commonly seen with conventional B-scan ultrasound, and has the same orientation as the standard radiographs but without ionizing radiation.

An Evaluation of Alternative Techniques for Monitoring Insulator Pollution

Electrical utility companies are constantly seeking predictive techniques that indicate the appropriate moment for maintenance intervention, while aiming toward a continuous increase in service indices. This paper proposes the use of pattern-recognition techniques to build classifiers that diagnose the operational state of the insulation structure in an online application. Important results were achieved during the study, mainly related to the types of sensors and features that need to be applied during the diagnosis process. Ultrasound and current leakage sensors, very-high frequency antenna, and thermovision instruments were employed to acquire signals and images in order to construct recognition systems. A number of specific features were applied to verify their importance during the classification process. Features were obtained in the time, frequency, and wavelet domains. Two groups of pattern-recognition techniques were applied: linear (Fisher and Karhunen-Loeve) and nonlinear (artificial neural network). The results indicated that pollution deposit can be evaluated by the proposed techniques, especially when a combination of sensors is employed.

An Accurate Machine for Real-Time Two-Phase Flowmetering in a Laboratory-Scale Flow Loop

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A new flow measurement system for real-time flow computation of a two-phase flow in an oil field is described. The system utilizes an array of ultrasound sensors together with capacitance and conductance sensors to accurately interpret the fluid composition in the whole water-cut range. The flow rate is determined using venturi and differential pressure techniques. A dedicated hierarchical neural network algorithm that relies on the various physical properties of the fluid was implemented and tested in a laboratory-scale flow loop. Experimental results demonstrated that real-time classification within a <formula formulatype="inline"><tex Notation="TeX">$\pm$</tex></formula>5% relative error in volumetric flow regardless of the flow regime or the fluid composition can be achieved. This is an improvement over traditional systems, where weak accuracy is usually obtained either within the 40%–60% water-cut range or in the case of a high water cut. </para>

High-sensitivity ultrasound interferometric single-mode polymer optical fiber sensors for biomedical applications

This work describes the results of ultrasonic wideband sensors based on single-mode polymer optical fibers that may be used for biomedical applications. We have compared the ultrasonic sensitivities of two Mach-Zehnder interferometric intrinsic optical fiber sensors. One is based on a single-mode polymethylmethacrylate optical fiber and the second on single-mode silica optical fiber, both operating at 632.8 nm. At a frequency of 1 MHz these sensitivities are 13.1 and 0.85 mrad/kPa, respectively. The ultrasonic phase sensitivity of the polymer optical fiber is more than 12 times larger than that from the fused silica fiber in the 1-5 MHz range.

Comparison of a New Cardiac Output Ultrasound Dilution Method With Thermodilution Technique in Adult Patients Under General Anesthesia

The purpose of this study was to investigate the reliability of cardiac output (CO) measured by a new ultrasound dilution method (COud) in comparison with CO by pulmonary artery thermodilution (COtd) in adult patients undergoing surgery. A prospective study. A university hospital, single institutional. Twenty-nine adult patients undergoing abdominal surgery. After approval of the institutional ethics review board, 29 adult patients were evaluated. After induction, radial and pulmonary artery catheters were inserted. A disposable extracorporeal AV loop was connected between existing arterial and central venous catheters. Reusable ultrasound sensors that measure changes in blood ultrasound velocity after dilution by isotonic saline were clamped onto the arterial and venous limbs of the loop. Ultrasound dilution (UD) measurements (COstatus; Transonic Systems, Inc, Ithaca, NY) were obtained by injecting 30 mL of body-temperature isotonic saline into the venous limb of the AV loop. An average of 3 COud and 5 COtd was obtained for comparison. Bland-Altman plot and correlation analysis were used for statistical comparison. A total of 142 comparison measurements were obtained. The correlation coefficient between the 2 techniques was r = 0.91. Bland-Altman analysis did not produce any significant bias (bias = 0.02, standard deviation = 0.56). The percentage error of these data was 23.53%. COud measurements agreed well with COtd. The results of this study indicated that COud might be interchangeable with conventional COtd in perioperative adult patients.

Comparison of high‐speed videokeratoscopy and ultrasound distance sensing for measuring the longitudinal corneal apex movements

Two different methods to measure binocular longitudinal corneal apex movements were synchronously applied. High-speed videokeratoscopy at a sampling frequency of 15 Hz and a custom-designed ultrasound distance sensor at 100 Hz were used for the left and the right eye, respectively. Four healthy subjects participated in the study. Simultaneously, cardiac electric cycle (ECG) was registered for each subject at 100 Hz. Each measurement took 20 s. Subjects were asked to suppress blinking during the measurements. A rigid headrest and a bite-bar were used to minimize undesirable head movements. Time, frequency and time-frequency representations of the acquired signals were obtained to establish their temporal and spectral contents. Coherence analysis was used to estimate the correlation between the measured signals. The results showed close correlation between both corneal apex movements and the cardiopulmonary system. Unraveling these relationships could lead to better understanding of interactions between ocular biomechanics and vision. The advantages and disadvantages of the two methods in the context of measuring longitudinal movements of the corneal apex are outlined.

Development research on high‐performance ultrasound sensor system

AbstractUltrasound sensor systems are widely used in various fields such as external environment sensors for autonomous mobile robots, mainly due to their features, small size, and easy construction. However, the conventional ultrasound sensor system is limited to measuring only the distance to the object at the time of reflection of the ultrasound wave. In this paper, a new type of high‐performance ultrasound sensor system is proposed. In this system, an ultrasound wave modulated by several featured frequencies is transmitted and the reflected waves are analyzed by means of the Fourier transform. At the same time, the system can measure the speed, the direction of the movement, and the surface ruggedness of the object. The effectiveness of the proposed system is demonstrated through experimental results. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 92(5): 23–30, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10034

Smart wheelchair perception using odometry, ultrasound sensors, and camera

SUMMARYThis paper deals with the perception mode of smart wheelchairs. First we evoke the many mobility aid prototypes developed in rehabilitation robotics by considering the point of view of perception. Then we describe the localization mode of the VAHM**. We show how the odometric, ultrasound, and vision sensors are used in a complementary way in order to locate the wheelchair in its known environment. The mode of adjustment of the odometric position by the least-squared method using ultrasonic measurements is detailed. Then the use of vision to perceive the vertical segments of the environment so as to refine the orientation is presented. The results of the tests carried out on the wheelchair are given and commented.

The Net in the Park

Ubiquitous Computing, Pervasive Computing, Physical Computing, Everyware, Tangible User Interface, and the Internet of Things all share the same viewpoint—a viewpoint that sees computers, phones, and game consoles as no longer being the only devices in our environment deemed worthy to embody computation and be connected. Each of these approaches focuses on slightly different aspects of the features and potentialities of the enabling technologies (i.e., Physical Computing focuses on the growing power of microcontrollers; IOT on the increasing influence of tagging systems; Everyware on the pervasiveness of the web through wired and wireless connections, etc.) We understand and place more emphasis on the similarities then the differences among these approaches, and at the same time, we try to address specific human activity issues by exploiting these new enabling technologies and visions. In the paper, we present a project, Wi-roni, that addresses two issues: in-person communication and the added value of being in a given location when accessing a given content. To this end, we considered in some detail the possibilities of three of these enabling technologies: ultrasound sensors, MEMS, and mash-up of Internet application. These technologies were chosen based on the nature of the human activity, and not vice versa. In Wi-roni, an Urban Architecture project located in the La Gora public park in Monteroni d'Arbia, a small village in the province of Siena (Italy), we developed two interconnect solutions: Wi-wave, a column for accessing web audio content in public spaces, and Wi-swing, a children’s swing that tells stories while swinging. These devices represent both the concrete grounds from which to begin to address the abovementioned human activity issues and the playground in which to explore the new, emerging interaction modalities that the enabling technologies could allow.

In vivo high-resolution 3D photoacoustic imaging of superficial vascular anatomy

The application of a photoacoustic imaging instrument based upon a Fabry–Perot polymer film ultrasound sensor to imaging the superficial vasculature is described. This approach provides a backward mode-sensing configuration that has the potential to overcome the limitations of current piezoelectric based detection systems used in superficial photoacoustic imaging. The system has been evaluated by obtaining non-invasive images of the vasculature in human and mouse skin as well as mouse models of human colorectal tumours. These studies showed that the system can provide high-resolution 3D images of vascular structures to depths of up to 5 mm. It is considered that this type of instrument may find a role in the clinical assessment of conditions characterized by changes in the vasculature such as skin tumours and superficial soft tissue damage due to burns, wounds or ulceration. It may also find application in the characterization of small animal cancer models where it is important to follow the tumour vasculature over time in order to study its development and/or response to therapy.

Novel tunable fiber-optic edge filter based on modulating the chirp rate of a π-phase-shifted fiber Bragg grating in transmission

We propose and experimentally demonstrate a novel fiber-optic edge filter based on modulating the chirp rate of a π-phase-shifted fiber Bragg grating (FBG) operating in transmission mode. The phase shift induced passband in the transmission spectrum is utilized as the edge filter. The dependence of the π-phase-shifted FBG’s transmitted spectral response on the chirp rate has been numerically studied in detail and experimentally confirmed, to the best of our knowledge, for the first time. The linear wavelength range of the proposed edge filter can be tuned by changing the chirp rate of FBG. The edge filter is further tested as a wavelength interrogator, and the experimental results are in good agreement with numerical results. The proposed fiber-optic edge filter has several unique advantages which include simple structure, cost effectiveness, high sensitivity, flexible tunability, and optical circulator is not required, and thus has interesting potential applications, especially as a wavelength interrogator in FBG foot sensors, FBG ultrasound and vibration sensors, and FBG distributed sensors, where the required wavelength ranges are very small (<0.4 nm).

Improvement of an Acknowledgement System of Customer Group Using Ultrasound Sensors

Improvement of an Acknowledgement System of Customer Group Using Ultrasound Sensors

Control of prehension for the transradial prosthesis: Natural-like image recognition system

We describe the hardware and software for the control of prehension for a dexterous transradial prosthesis. The prehension process comprises hand orientation (three degrees of freedom) and the opening of the hand in a manner that is appropriate for the shape and size of the object. The hardware consists of a standard web camera, accelerometer, ultrasound distance sensor, laser pointer and an LED illumination system. Software operating in real time estimates the shape and size of the object as well as the relative orientation of the hand with respect to the object. Based on this data, the controller generates signals that are sent to the three-dimensional (3D) wrist rotator, and drives which control fingers and thumb of the transradial prosthesis, thereby preparing the hand for palmar, lateral, or precision (2-digit or 3-digit) grasps. The choice of the grasp follows heuristics captured from healthy humans when grasping and expressed in the form of IF-THEN rules.

RECYCLING OF MIXED POLYOLEFIN WASTES

The mass of usage of secondary plastics are mostly determined by their quality and price. Therefore it was essentially to collect and evaluate the related aspects and expectations from the potential secondary-plastics users. To enable this in the frame of the W2Plastics EU7 project (Magnetic Sorting and Ultrasound Sensor Technologies for Production of High Purity Secondary Polyolefins from Waste) an adequate questionnaire was worked and sent out to automotive plastics end-product manufacturers. With the evaluation of these questionnaires basic parameters for the technology development in the frame of W2Plastics project were determined.