Cervical Carotid Imaging With a ContinuousWave Doppler Flowmeter • A noninvasive technique for carotid arteriography using an ultrasonic directional Doppler flowmeter to image the carotid bifurcations is described. The technique uses a position sensing arm to hold the sharply focusing probe and translates the position of arterial flow onto an image storage screen. By multiple manual sweeps acro...

ultrasonic machining (usm) is a mechanical material removal process used to erode holes and cavities in hard or brittle work pieces by using shaped tools, high-frequency and an abrasive slurry. this paper addresses the concept and development of an expert system (es) for hard and brittle material, such as glass, quartz, diamond, carbides, semi conducting materials, ceramic and graphite which ca...

Time-reversed ultrasonically encoded (TRUE) optical focusing was recently proposed to deliver light dynamically to a tight region inside a scattering medium. In this letter, we report the first development of a reflection-mode TRUE optical focusing system. A high numerical aperture light guide is used to transmit the diffusely reflected light from a turbid medium to a phase-conjugate mirror (PC...

Time-reversed ultrasonically encoded optical focusing measures the wavefront of ultrasonically tagged light, and then phase conjugates the tagged light back to the ultrasonic focus, thus focusing light deep inside the scattering media. In previous works, the speed of wavefront measurement was limited by the low frame rates of conventional cameras. In addition, these cameras used most of their b...

Photoacoustic microscopy was developed to achieve volumetric imaging of the anatomy and functions of the subcutaneous microvasculature in both small animals and humans in vivo with high spatial resolution and high signal-to-background ratio. By following the skin contour in raster scanning, the ultrasonic transducer maintains focusing in the region of interest. Furthermore, off-focus lateral re...

when testing the defect by ultrasonic time of flight diffraction (TOFD), the image signal detected is often reshaped and resulted in inaccuracy of defect measurements because the probe beam has a limited range. This paper proposed an image enhancement method based on synthetic aperture focusing technique (SAFT). A mathematical model of testing image was first established based on the generation...

This paper proposes a deep learning framework for artefact identification and suppression in the context of non-destructive evaluation. The model, based on concept autoencoders, is developed enhancing ultrasound inspection defect through images obtained from full matrix capture data total focusing method. An experimental case study used to prove effectiveness method while exploring its practica...

A 1 × 16 capacitive micro-machined ultrasonic transducer linear array was designed, fabricated, and tested for underwater imaging in the low frequency range. The linear array was fabricated using Si-SOI bonding techniques. Underwater transmission performance was tested in a water tank, and the array has a resonant frequency of 700 kHz, with pressure amplitude 182 dB (μPa·m/V) at 1 m. The -3 dB ...

A new ultrasonic phased array transducer to increase the imaging resolution of the borehole wall is presented for acoustical logging. We fabricate a cylindrical phased array which is made up of 128 piezoelectric elements distributed on the surface of a cylinder uniformly. The working frequency of each element is 0.5MHz. Through the switch array, different combinations of the elements can lead a...

The time and Fourier domain Synthetic Aperture Focusing Technique (SAFT and FSAFT) have been used to improve both sensitivity and lateral resolution of ultrasonic NDT. Following acquisition of signals over the surface of the tested piece, SAFT identifies a defect by summing all the signals within a certain area (the aperture) after giving proper time-delays. FSAFT, although using the same data,...