34 results about "Laser vibrometry" patented technology

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 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.

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.

An optical system provides information about tangential vibration components of a surface at remote location. The optical system includes a light source assembly that emits first and second beams, each having one or more wavelengths and one or two polarizations. The first and second beams are directed to the interrogated surface. A detector system is positioned to detect a third beam formed by at least a portion of the first and second beams being reflected from the interrogated surface. The first, second and third beams having incident and reflection angles relative to the interrogated surface that do not lay in a same plane. The detector system positioned remotely from the interrogated surface, and providing information on a phase change in the third beam relative to the first and second beam. The phase change is indicative of at least one surface vibration vector component of the interrogated surface. The detector system is a 90 degree optical hybrid balanced detector with four photodiodes.

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 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 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.

The invention discloses an electric control compression testing machine and testing method for in-situ imaging by using high-energy X-rays. A high-precision servo motor is adopted for actuation; the rotary motion of the motor is converted into the up-and-down linear motion of the lower clamp by utilizing a two-stage worm gear reducer; a sample is fixed through the upper clamp and the lower clamp,compressive stress is applied to the sample through displacement control of the lower clamp, loads and displacement borne by the sample in the testing process are collected in real time through the miniature dynamic force sensor and the laser vibrometer, and closed-loop control over the testing machine is achieved through the control unit. The testing machine disclosed by the invention is an in-situ compression material testing device which has the characteristics of high precision, large load, small size, light weight, capability of realizing monotonous compression and the like; good compatibility with a synchrotron radiation light source test platform can be realized, the requirements of a sample platform on weight and size are met, and the internal structure and typical defects of a material under various monotonous loading stress levels can be monitored in real time.

An acoustic sensing device includes a housing having an internal cavity filled with a vibration decoupling medium. An acoustic window formed of an acoustically transparent material is mounted in the housing. This mounting can be by antivibration mounts to prevent housing noise from affecting the acoustic window. A scanning laser vibrometer is positioned within the housing and directed to detect vibrations of the acoustic window. Antivibration mounts are joined between said scanning laser vibrometer and said housing. In further embodiments, the scanning laser vibrometer detects vibrations at a plurality of locations on the acoustic window forming a virtual array.