Optical Sound Measurement

Optical coherence tomography enables accurate measurement of equine cartilage thickness for determination of speed of sound

Background and purpose - Arthroscopic estimation of articular cartilage thickness is important for scoring of lesion severity, and measurement of cartilage speed of sound (SOS)-a sensitive index of changes in cartilage composition. We investigated the accuracy of optical coherence tomography (OCT) in measurements of cartilage thickness and determined SOS by combining OCT thickness and ultrasoun...

Optical measurement of the speed of sound in air over the temperature range 300-650 K.

Using laser-induced thermal acoustics (LITA), the speed of sound in room air (1 atm) is measured over the temperature range 300-650 K. Since the LITA apparatus maintains a fixed sound wavelength as temperature is varied, this temperature range simultaneously corresponds to a sound frequency range of 10-15 MHz. The data are compared to a published model and typically agree within 0.1%-0.4% at ea...

Measurement of sound propagation in glass wool

Sound velocity measurement using transfer function method

Abstract The transfer function of a piezoelectric transducer, buffer rod and sample assembly is used to measure the sound velocity of solid materials. From the recorded transfer function, pulse echo patterns at frequencies of the passband of the input signal are reproduced after convoluting with monochromatic RF input signals. The time delay is obtained by performing pulse echo overlap and phas...

Psychological measurement for sound description and evaluation

Several domains of application require one to measure quantities that are representative of what a human listener perceives. Sound quality evaluation, for instance, studies how users perceive the quality of the sounds of industrial objects (cars, electrical appliances, electronic devices, etc.), and establishes specifications for the design of these sounds. It refers to the fact that the sounds...