Limited-view acquisition suffers from artefacts and loss of resolution for reconstruction-based Photoacoustic Imaging (PAI). In this paper, a completely new acquisition and reconstruction scheme is reported to achieve artefact-free imaging from limited-view acquisition. The method employs spatially and temporally varying random optical illumination instead of the uniform illumination used in co...

Ultrasonic pulse-echo methods are versatile, effective procedures for inspecting welds in steel structures. However, the ultrasonic methods conventionally used have two disadvantages: inspection must be performed manually by a skilled technician, and the signal obtained at the time of one inspection provides no “memory” to be used at the time of a later inspection. Our research involves the dev...

The measurement principle of the transit time difference method of the ultrasonic flowmeter is presented. The hardware structure and realization method are introduced. The software function and work mode are overviewed. In order to enhancing flowmeter's precision and stability a Xilinx CoolRunner CPLD and a Texas Instruments microcontroller from MSP430 family are applied in high precision timin...

Ultrasonic pulse-echo methods are versatile, effective procedures for inspecting welds in steel structures. However, the ultrasonic methods conventionally used have two disadvantages: inspection must be performed manually by a skilled technician, and the signal obtained at the time of one inspection provides no “memory” to be used at the time of a later inspection. Our research involves the dev...

The Radiation Force Balance (RFB) technique is well established and most widely used for the measurement of total ultrasonic power radiated by ultrasonic transducer. The technique is used as a primary standard for calibration of ultrasonic transducers with relatively fair uncertainty in the low power (below 1 W) regime. In this technique, uncertainty comparatively increases in the range of few ...

Piezoceramics have been the dominant transducer technology in ultrasound medical imaging for several decades. Recent progress in surface micromachined capacitive ultrasonic immersion transducers makes them an alternative transducer technology, especially in highly integrated twodimensional arrays. This paper demonstrates that the surface micromachined capacitive ultrasonic immersion transducer ...

A simple method for imaging ultrasonic fields in clear media is introduced. A modulated laser source is used to project the ultrasonic field onto a CCD camera. By use of the source-synchronized lock-in detection scheme, 2D images of the amplitude and phase distributions can be determined simultaneously. This technique is experimentally demonstrated with a 1-MHz and a 3.5-MHz ultrasonic transduc...

The fluids speed measurement, particularly the air speed measurement is very important for industrial and laboratory applications. The ultrasonic method is among the most common methods used for determining the air speed. The basic principle to measure a fluid speed, using an ultrasonic transducer, is based on the modification of the apparent propagation speed of an ultrasonic signal caused by ...