Topic
Laser Doppler vibrometer
About: Laser Doppler vibrometer is a research topic. Over the lifetime, 6319 publications have been published within this topic receiving 76068 citations.
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TL;DR: The objective of the present study is to characterize the effect of changes in scanning speed on texture-elicited vibrations to better understand how the exploratory movements shape the neuronal representation of texture.
Abstract: To sense the texture of a surface, we run our fingers across it, which leads to the elicitation of skin vibrations that depend both on the surface and on exploratory parameters, particularly scanning speed. The transduction and processing of these vibrations mediate the ability to discern fine surface features. The objective of the present study is to characterize the effect of changes in scanning speed on texture-elicited vibrations to better understand how the exploratory movements shape the neuronal representation of texture. To this end, we scanned a variety of textures across the fingertip of human participants at a variety of speeds (10-160 mm s-1) while measuring the resulting vibrations using a laser Doppler vibrometer. First, we found that the intensity of the vibrations-as indexed by root-mean-square velocity-increases with speed but that the skin displacement remains constant. Second, we found that the frequency composition of the vibrations shifts systematically to higher frequencies with increases in scanning speed. Finally, we show that the speed-dependent shift in frequency composition accounts for the speed-dependent change in intensity.
25 citations
TL;DR: In this article, a new technique was proposed and applied to study the frequency drift of an external-cavity semiconductor laser, locked to the transmission resonances of a thermally stabilised Fabry-Perot interferometer.
Abstract: A new technique is proposed and applied to study the frequency drift of an external-cavity semiconductor laser, locked to the transmission resonances of a thermally stabilised Fabry–Perot interferometer. The interferometer frequency drift is measured to be less than 2 MHz h-1. The laser frequency is measured using an Angstrom wavemeter, calibrated using an additional stabilised laser. It is shown that this system of laser frequency control can be used to identify Rydberg transitions in ultracold 7Li atoms.
25 citations
TL;DR: In this paper, an experimental technique is proposed to characterize a small dimensional structure surrounded by various air pressure levels, based on the logarithmic decrement method applied in the time-frequency domain using a wavelet transform of the time responses.
25 citations
Patent•
07 Mar 2001TL;DR: In this article, a modulated beat frequency generation controller was proposed to enable vibration conditions of a measured object to be measured with high accuracy independently of a laser oscillating wavelength using self-mixture of a returning beam obtained when the oscillated emitted beam is reflected by the measured object with a beam oscillated and emitted when the returning beam is received.
Abstract: To enable vibration conditions of a measured object to be measured with high accuracy independently of a laser oscillating wavelength. A vibration measuring means includes a laser resonator for oscillating a laser beam and generating beat waves through self-mixture of a returning beam obtained when the oscillated emitted beam is reflected by the measured object with a beam oscillated and emitted when the returning beam is received, a modulated beat frequency generation controller 8 for providing the beat waves with a modulated beat frequency that is higher than a Doppler frequency that is superposed on the returning beam while varying depending on a speed of the measured object, and a signal processor 21 for executing signal processing on the beat waves generated by the self-mixture in the laser resonator and outputting a result of the processing as vibration information. The signal processor 21 comprises a vibration information generator 22 for generating vibration information from the beat waves by defining variations in the frequency of the beat waves as variations in frequency from a modulated beat frequency by the amount of a Doppler frequency.
25 citations
Patent•
21 Jan 1986TL;DR: In this article, an up/down counter whose count determines the level of driving current to be applied to a laser driver which drives the semiconductor laser is used to control the output intensity of the laser beam.
Abstract: A semiconductor laser output intensity control device is provided in a laser beam scanning system, such as a laser printer. A laser beam emitted from a semiconductor laser is modulated by image information and scanned across a photosensitive member for forming an image thereon. The present output intensity control device employs an up/down counter whose count determines the level of driving current to be applied to a laser driver which drives the semiconductor laser. The up/down counter changes its count either up or down depending on the magnitude of the output intensity of the laser beam as compared with a reference level. The present device includes a control circuit which prevents the power setting operation of the laser from taking place during a scanning time period in which the photosensitive member is scanned by the laser beam.
25 citations