35 results about "Laser vibrometry" patented technology

An apparatus for measuring at least one parameter associated with a fluid flowing within a pipe comprises an optical measurement device and a signal processor. The optical measurement device provides output signals indicative of unsteady pressures within the fluid at two or more axial locations along the pipe in response to light reflected from an outer surface of the pipe. The signal processor provides an output signal indicative of at least one parameter associated with the fluid in response to the output signals. The optical measurement device may include, for example, an electronic speckle pattern interferometer, a Fabry-Perot device, and / or a laser vibrometer. The at least one parameter may include at least one of: density of the fluid, volumetric flow rate of the fluid, mass flow rate of the fluid, composition of the fluid, entrained air in the fluid, consistency of the fluid, size of particles in the fluid, and health of a device causing the unsteady pressures to be generated in the pipe.

A system and method for generating ultrasound images of a subject without physically contacting the subject is provided. A photoacoustic excitation source may be employed that directed into a scanning mirror to transmit acoustic disturbances into a patient to induce propagating photoacoustic waves. The acoustic disturbances are translated along the patient in a defined direction to cause coherent summation of the propagating photoacoustic waves and, thereby, a resultant acoustic and / or elastic wave to probe structures within the patient. Vibrations created by the backscatter of the resultant wave are detected at the surface of the patient and ultrasound images of the structures within the patient are generated. Detection of the vibrations may be performed using a laser vibrometer. The excitation and detection systems may be used separately or in combination.

The invention is a system for acquiring and mapping the location of a human target within a targeted zone defined by boundaries. The system includes a remote sound detection component, which may be a laser vibrometer, capable of placement at a remote safe distance without physical attachment at the targeted zone which detects sound from within the targeted zone, thereby generating a sound signal accurately representing characteristics of the detected sound. Further, a sound processing computer receives and analyzes the sound signal to determine the location of the sound relative to the targeted zone and generates a location signal representing the location of the sound. A target display is provided for receiving the location signal and outputting an accurate visual representation at the location of the target relative to the boundaries of the targeted zone.

Provided are an alignment method and an alignment apparatus, in which the number of times to carry out alignment operation is reduced to reduce damage of a substrate and a mask and improve the productivity of evaporation using the mask. Vibrations in the direction of gravity of a substrate immediately after the substrate is brought in are measured by a laser vibrometer. Based on the obtained vibration data, a vibration control portion generates an antiphase vibrational wave. After the vibrational wave is applied to the substrate to reduce the vibrations of the substrate, the alignment between the substrate and a mask is carried out.

The present invention generally relates to improved non-destructive thickness measurement systems and methods. Embodiments of the present invention utilize quarter wave resonant frequency to measure the thickness of high-temperature pipe walls. In one embodiment, an improved non-destructive thickness measurement system is provided that utilizes Gaussian white noise to produce maximum mechanical resonance in the pipe wall and laser vibrometers to detect the pipe wall's maximum displacement.

Methods and apparatus for exciting a structure and determining its structural integrity. In particular, methods of nonlinear analysis are used to compare first and second response datasets, each dataset resulting from a different excitation amplitude that the other dataset.

A method and system are provided for inspecting a surface of an object with an optical scanner and a laser vibrometer. The method includes the steps of: (a) mapping at least a portion of the object surface using the optical scanner; (b) projecting a beam of light from the laser vibrometer onto the object surface at a measurement point; (c) locating the measurement point relative to the object surface using the optical scanner; and (d) measuring a position of the object surface using the laser vibrometer to determine, for example, a deflection of the object surface.

A method and system for remotely inspecting the integrity of a structure. This can be performed by a method creating a vibratory response in the structure from a remote location and then measuring the vibratory response of the structure remotely. Alternatively, this can be performed by a system for remotely measuring the integrity of a structure using a vehicle and an artificial neural network, where the vehicle is equipped with a vibratory response device. The vibratory response can be produced by infrasonic and audio frequencies that can be produced by at least a vehicle, motor, or sound recording. The vibratory response can be measured with a laser vibrometer or an audio recording device.

A system and method for noncontact ultrasound imagery capable of generating images in a manner that is safer for eyes and skin is provided. A photoacoustic excitation source may be employed to direct light signals with wavelengths of 1400-1600 nanometers into the patient to generate acoustic disturbances that induce propagating photoacoustic waves. The acoustic disturbances may be translated in defined directions to cause coherent summation of the propagating photoacoustic waves and, thereby, generate a resultant acoustic and / or elastic wave to probe structures within the patient. Vibrations created by the scatter of the resultant wave are detected at the surface of the patient and ultrasound images of the structures within the patient may be generated. Detection of the vibrations may be performed using a laser vibrometer. The excitation and detection systems may be used separately or in combination. Ultrasound images can be generated without physically contacting the patient.

The infrasound generating device based on a displacement-feedback type vibration exciter comprises a displacement-feedback type vibration exciter system, an infrasound generating chamber (3) and a laser vibrometer (1); the displacement feedback mechanism is adopted in the vibration exciter (2). The piston (31) is driven by the vibration exciter to move in a sinusoidal manner in the cavity (35) of the airtight infrasound generating chamber (3) and the standard infrasonic pressure signal with low harmonic distortion can be achieved. The displacement of the moving part (22) of the vibration exciter (2) can be measured by the laser vibrometer (1) through the measurement beam (15) injecting into the vibration exciter (2) through the optical channel running through the vibration exciter and the standard infrasonic pressure can also be obtained. The value of the standard sound pressure produced by the infrasound generating chamber is calculated. Such value is used as the calibration reference for the infrasound sensors (4) to be calibrated in order to achieve the primary calibration of the infrasound sensors. The standard infrasonic sensor can be installed inside the infrasound generating chamber (3) and the output of the standard infrasonic sensor can be used as the reference for the infrasonic sensor (4) to be calibrated in order to achieve the secondary calibration of the infrasound sensors. This invention has the advantages of technical maturity, high feasibility, easy to realize, high calibration accuracy and so on.

Methods for tracking the relative velocity between a vehicle and a target that uses both a measured velocity as well as an estimate of the velocity that is based on tracking the peaks in a laser vibrometer return signal.

A laser vibrometer makes non-contact measurements of vibrations of a target. A laser produces a laser beam, and a beamsplitter splits the laser beam into a reference beam and a first target beam. A first frequency shifter / splitter splits the first target beam into a pair of target beams each having a frequency different than a frequency of the other target beams. The target beams are reflected from the target to a detector, and the reference beam is combined with the target beams such that the detector receives the target beams and reference beam together.

A laser vibrometer for measurement of ambient chemical species includes a laser that produces a beam that is split into a reference readout beam and a signal readout beam. A probe laser beam is tuned to an absorption feature of a molecular transition, and generates acoustic signals when incident on a gaseous species via the photo acoustic effect. The scattered acoustic signals are incident on a thin membrane that vibrates. The readout laser beam reflected from the vibrating membrane is mixed with the reference beam at the surface of a photo-EMF detector. Interferrometric fringes are generated at the surface of the photo-EMF detector. Electric current is generated in the photo-EMF detector when the fringes are in motion due to undulations in the signal readout beam imparted by the vibrating membrane. A highly sensitive photo-EMF detector is capable of detecting picoJoules or less laser energy generated by vibrating processes.

A laser vibrometer for measurement of ambient chemical species includes a laser that produces a beam that is split into a reference readout beam and a signal readout beam. A probe laser beam is tuned to an absorption feature of a molecular transition, and generates acoustic signals when incident on a gaseous species via the photo acoustic effect. The scattered acoustic signals are incident on a thin membrane that vibrates. The readout laser beam reflected from the vibrating membrane is mixed with the reference beam at the surface of a photo-EMF detector. Interferrometric fringes are generated at the surface of the photo-EMF detector. Electric current is generated in the photo-EMF detector when the fringes are in motion due to undulations in the signal readout beam imparted by the vibrating membrane. A highly sensitive photo-EMF detector is capable of detecting picoJoules or less laser energy generated by vibrating processes.

A measuring method to determine the noise emission of an electric motor is proposed in which the vibrational excitation of the running electric motor is measured by a laser vibrometer device and this measured vibrational excitation is correlated with a noise level.

A generalized magnetoelectric effect energy conversion method based on a cantilever beam comprises the following steps of 1, fixing one end of a PVDF piezoelectric film, fixing the cantilever beam structure to the middle of a Helmholtz coil and the middle of the two poles of an electromagnet, such that the direction of an alternating-current magnetic field is perpendicular to the direction of a direct-current magnetic field, 2, setting an alternating-current magnetic field emitted by a Helmholtz coil to obtain a relationship between the output voltage of the PVDF sample and the direct-current magnetic field, 3, setting a magnetic field generated by the direct-current magnetic field generator, obtaining a current response by using a current amplifier and a lock-in amplifier, and obtaining a relationship between the output voltage of the PVDF sample and the frequency of the alternating-current magnetic field, 4, testing vibration parameters of the PVDF piezoelectric film by using a laser vibrometer system consisting of a sensor and a laser controller, and verifying that the researched electromagnetic effect is an electromagnetic coupling phenomenon through mechanical coupling interaction. The device has the characteristics of accurate and convenient magnetoelectric effect energy conversion.

A laser vibrometer for measuring the vibratory characteristics of an object and more specifically, a moving object, has an improved signal to noise ratio due to multiple channels. A laser is split into a plurality of channels and then for each channel split again into a reference beam and a probe beam. The probe beam is directed at the object and the back scattered reflections are collected and compared to the reference beam to determine the vibratory characteristics of the object. The received signals from the multiple channels are different, sequential and non-overlapping.

A non-invasive system for detection of explosives and contraband in a vehicle includes at least one laser vibrometer for measuring vehicle vibrations at one or more points on the vehicle while the vehicle is operating. One laser vibrometer can be sequentially directed to various points on the vehicle according to a predetermined single point or pattern. Or, a plurality of laser vibrometers could be used to simultaneously illuminate the vehicle. After measurement, the vehicle vibrations are compared to a database of reference vibrations, which that were taken of similar vehicles that were known to be contraband-free. The measured vibrations are compared to the vibrations pattern for the same type of vehicle. If the vibration patterns exhibit differences in frequency peaks that exceed predetermined parameters, the system alerts the operator. A more detailed inspection of the vehicle can then be accomplished.