Optonor As

Statoil Asa

Statoil Petroleum As

Elkem Technology A/s

Eiolf Vikhagen

Paul Meldahl

Yngve Strom

Jan T Malmo

Johan Ole Lokberg

Karl O Bjornestol

A system is used to excite an object at a vibration frequency, in order to induce stationary or travelling waves having the vibration frequency on the surface of the object. An optical interferometer is configured to use optical interference to determine vibration amplitude and phase data of the stationary or travelling wave at each of a plurality of points on the surface, relative to a reference phase. A processing system is used to apply a spatial derivative filter to the vibration phase data, and the resulting spatial-derivative-of-phase data is processed to determine a property of the object, and is further processed to generate graphical-representation data for outputting on a display device.

Optical-interference analysis

An optical interferometer () is used to determine information about the position, gradient or motion of a surface of an object () at each of a plurality of points on the surface. An image is projected onto the surface of the object (), such that, for each of the plurality of points, the intensity or spectrum of the projected image at that point depends on the determined information about the position, gradient or motion of the surface at that point.

Optical interferometry

Method and system for measuring vibration in two or three directions in objects () by using three illumination light beams (A-C) for measurement of in-plane vibrations in two directions, where one of the three illumination light beams (A-C) is common for the two in-plane measurements, and where the three illumination light beams (A-C) are configured to provide free space at one side of the object () for easier access to the object. The method and system is further arranged for using two illumination light beams (A-B) for measuring vibrations in the object () in a third direction, which third direction is out-of-plane direction, where one illumination light beam (A) is illuminating the object () through an imaging objective () and one illumination light beam (B) is used as reference beam.

Method of vibration measurement and interferometer

A interferometer apparatus for studying the surface of an object, the apparatus comprising a source producing an object beam of coherent light, a source producing a reference beam which is coherent with the object beam, and a detector or a plurality of detectors arranged in a line or array, wherein the apparatus is arranged such that the object beam is diverging or substantially collimated, and wherein, in use the diverging or substantially collimated object beam is directed towards the surface of the object to produce a reflected object beam reflected from the surface of the object, the detector(s) is/are focused to a point beneath the surface of the object, and the reflected object beam is combined with the reference beam and detected by the detector(s). Also provided is a corresponding method for conducting an interferometric study of the surface of an object. The surface of the object may be a sea floor, and the interferometer apparatus may be for studying the movement of particles on the sea floor in response to a seismic event.

Interferometric methods and apparatus for seismic exploration

A method and apparatus for carrying out a seismic exploration. A seismic event is applied to the earth's surface, particles at the earth's surface move in response to the event and the response to the event is detected using an interferometer. The earth's surface and the interferometer move with respect to each other. The detectors of the interferometer may be arranged in an array. The detected response may be analyze.

Seismic exploration

A method of studying a surface using an interferometer, in which there is relative motion between the surface and the interferometer, the motion having a total velocity Vwhich includes a transversal or traversing component Vand a longitudinal component V. The method comprises: directing an object beam of coherent light to a measurement position at the surface, whereby there is relative motion between the surface and the measurement position; arranging an array of detectors on the interferometer in a line extending generally in the transversal direction, the detectors being arranged to detect light rays with different angular directions, representing different sensitivity directions; producing a reference beam of coherent light which is coherent with the abject beam; combining the reference beam with the reflected object beam from the surface to produce a cross interference in the speckle pattern providing information about the relative motion of the surface and the interferometer; detecting the speckle pattern and the cross interference pattern with the detectors; determining which detector in the array has zero or minimum sensitivity to the total velocity Vof the motion, thereby identifying the detector with a sensitivity direction line that is normal to V; monitoring the temporal change in which of the detectors has zero or minimum sensitivity, thereby ascertaining the change in direction of Vover time, brought about by changes in V: and determining temporal changes in V.

Method and apparatus for studying surface vibrations by moving speckle interferometer

An instrument for studying an object () comprising a movable interferometer having a laser source and a plurality of detectors () arranged in an array. The laser source is expanded and arranged to direct a converging object beam () towards a point () or line beyond the object () whereby a speckle pattern of light reflected from the object () is detected by the detector or detector array (). The point () or line at which the laser source is arranged to converge the object beam () is approximately the same distance beyond the object () as the object is spaced from the source. The speed of movement of the instrument, the sampling rate of the detectors () and size of the area () of the object illuminated by the converging laser object beam () are arranged so that sequential areas () of the object () studied overlap.

A Method for measuring vibrations in small and microscopic objects is disclosed. The method includes the steps of vibrating the object at a frequency, illuminating the object with a light source which is phase modulated at the same frequency, collecting data from a detector array, operating an algorithm to calculate the size of interference modulation between the light waves, operating an algorithm based on multiple calculation of the modulation at different vibration phases between the excitation of the object on one hand, and the reference phase modulation on the other, and operating an algorithm based on use of the result from the calculation of the second modulation, calculating amplitude values and phase values for the vibration of the surface of the object.

Method for vibration measurement and interferometer

Continuously cast metal billets are continuously passed by a symmetric light source comprising a plurality of single light sources arranged in a circle or in another way such that the light falls substantially symmetrically on the part of the surface of the metal billet which is to be detected in such a way that the surface of the metal billet which faces the light source is illuminated except for pinholes. Reflected light from the surface of the billet is detected by a linescan camera arranged centrally in relation to the light source, which camera has a scanning direction normal to the direction of movement of the metal billet, whereby pinholes are detected by registration of reflected light intensity below a preset threshold value.

Growing community of inventors

Trondheim, Norway

Eiolf Vikhagen