1302 results about "Plane wave" patented technology

A biometric scanner is described and claimed. The scanner has a platen, an ultrasonic plane wave generator, an ultrasonic detector, and a delay layer residing between the generator and the detector.

Present configuration concerns microelectronics; for instance, compact antenna devices applied in mobile communications and other equipment operating in millimeter range. The controlled lens antenna apparatus may include antenna elements in an integrated circuit configured to transmit beams. The apparatus may also include a dielectric lens antenna configured to generate a plane wave based in the beams transmitted. The apparatus may include a plate configured to deflect the generated plane wave at a random angle.

An audio processor for converting a multi-channel audio input signal, such as a B-format sound field signal, into a set of audio output signals, such as a set of two or more audio output signals arranged for headphone reproduction or for playback over an array of loudspeakers. A filter bank splits each of the input channels into frequency bands. The input signal is decomposed into plane waves to determine one or two dominant sound source directions. The(se) are used to determine a set of virtual loudspeaker positions selected such that the dominant direction(s) coincide(s) with virtual loudspeaker positions. The input signal is decoded into virtual loudspeaker signals corresponding to each of the virtual loudspeaker positions, and the virtual loudspeaker signals are processed with transfer functions suitable to create the illusion of sound emanating from the directions of the virtual loudspeakers. A high spatial fidelity is obtained due to the coincidence of virtual loudspeaker positions and the determined dominant sound source direction(s). Improved performance can be obtained in the case where Head-Related Transfer Functions are used by differentiating the phase of a high frequency part of the HRTFs with respect to frequency, followed by a corresponding integration of this part with respect to frequency after combining the components of HRTFs from different directions.

A method for enhancing vision of an eye includes a laser delivery system having a laser beam for ablating corneal material from the cornea of the eye. Measurements are made to determine an optical path difference between a plane wave and a wavefront emanating from the retina of the eye for a location at a surface of the cornea. An optical correction is provided to the laser delivery system for the location based on the optical path difference and refractive indices of media through which the wavefront passes. The optical correction includes dividing the optical path difference by a difference between an index of refraction of corneal material and an index of refraction of air. The laser beam is directed to the location on the surface of the cornea and corneal material ablated at the location in response to the optical correction to cause the wavefront to approximate the shape of the plane wave at that location.

The invention provides a SRP-PHAT multi-source spatial positioning method. The method comprises the steps that the number and spatial positions of all microphones in a uniform circular microphone array are assumed to be unchanged in the data obtaining process at first, the isotropous microphones are evenly distributed on a circumference which has the radius r and is located on an x-y plane, the direction of arrival of a plane wave s is expressed by polar coordinates, the original point of the coordinate system is located on a circle center position of the circular array, multiple sound source signals are divided into non-overlapped time frequency point sets, each time frequency window contains only one movable source signal, and weak W orthogonal separation conditions are met; a Hamming window is selected, a controllable response power function is calculated and a target function is obtained through a SRP-PHAT algorithm, wave beams are controlled to carry out scanning in all the possible receiving directions, and the wave beams output the direction value with the maximum power to obtain the direction of a sound source, so that the DOA estimation of the multiple sound sources has the better separating performance in the strong noise and moderate reverberation acoustic environment, the real peak value is obviously outstanding, and high positioning precision is achieved.

A method for estimating near-surface material properties in the vicinity of a locally dense group of seismic receivers is disclosed. The method includes receiving seismic data that has been measured by a locally dense group of seismic receivers. Local derivatives of the wavefield are estimated such that the derivatives are centered at a single location preferably using the Lax-Wendroff correction. Physical relationships between the estimated derivatives including the free surface condition and wave equations are used to estimate near-surface material properties in the vicinity of the receiver group. Another embodiment of the invention is disclosed wherein the physical relationships used to estimate material properties are derived from the physics of plane waves arriving at the receiver group, and the group of receivers does not include any buried receivers.

The invention relates to a multimodal orbital angular momentum multiplexing system and method. The system comprises a transmitting device and a receiving device which are in mutual communication connection. The transmitting device comprises a bit level processing module, a constellation mapping module, an orbital angular momentum modulation module, a digital domain orbital angular momentum multimodal multiplexing module, a DAC module, an upper conversion module and a ring array transmitting antenna. The receiving device comprises a ring array receiving antenna, a down conversion module, an ADC module, a digital domain orbital angular momentum demodulation and demultiplexing module and a detection decoding module. According to the system and the method, a vortex electromagnetic wave multimodal OAM (Orbital Angular Momentum) multiplexing communication technology of which physical feature is clearly different from that of a traditional plane wave is realized; the spectral efficiency and the transmission rate are multiplied; and the improvement space and potential of the modal multiplexing quantity is further expanded. The system and the method can be applied to the multimodal OAM multiplexing communication system in a microwave or millimeter wave band.

An apparatus forms a weight for each signal path associated with an antenna of a plurality of antennas around a test zone in an over-the-air chamber by a comparison of a desired target electric field based on a radio channel model and an electric field obtainable by the plane waves associated with the test zone, the plane waves being transmittable by the antennas and being based on at least one basis waveform in each signal path.

A subjective refraction technique uses a plane wave light source including substantially a point as a viewing target. The refraction method provide for a number of distinct identifiable end points. By finding such end points the process leads to an aberration-corrected vision. A defocus corrector assembly (DCA) includes a lens that is moveable along an optical axis between a patient's eye and the point light source for adjusting defocus power until the patient indicates that the blurry image has become a relatively focused line image. An astigmatism corrector assembly (ACA) which is capable of continuously variable in its amplitude is provided including a pair of astigmatism plates for adjusting astigmatism power and axis angle. The ACA is adjusted until the patient indicates that the line image has become a substantially round image. A reference marker provides displayed items including a sweep line overlapping at the point source and having an orientation which is adjustable. The patient may subjectively control the sweep angle of the sweep line and indicate that the sweep line is aligned with the sharp line image of the point source, thereby providing axis angle data of astigmatism errors of the patient's eye.

A method for producing a durable electromagnetic and radio frequency interference shield between two or more structural members of a wall or enclosure and a shielded shelter produced using the method. In one embodiment, joints between structural members are preferably filled with an electrically conductive filler. A base coat of a metal spray that adheres well to the filler and structural member is then applied. At least one layer of a metal spray with magnetic field attenuation properties such as steel, and at least one layer of a metal spray that has plane wave attenuation properties such as tin are applied to the base coat. Optionally, a coat of protective or conductive paint is then applied to the top surface of the metal spray layers. An enclosure with shielded joints according to the present invention has superior shielding capability and durability over the art.

The invention relates to a method using three-dimensional mechanics characteristics and tissue specific imaging of blood vessels and plaques for detection. The method is on the basis of a multi-beam focus wave and superfast plane wave alternative transmitting sequence and can also be extended to a line-by-line scan imaging manner; the forms and the functions of the blood vessels and the plaques are evaluated and imaged respectively from the aspects of the radial-direction, circumferential and axial-direction three-dimensional mechanics characteristics, blood vessel wall shear rate, plaque form and tissue characterization, and the like; the new method which is provided for detection of the vulnerable plaques of a carotid artery is regarded as the improvement of the existing method.

Vector Doppler Imaging (VDI) improves on conventional Color Doppler Imaging (CDI) by giving speed and direction of blood flow at each pixel of a display generated by a computing system. Multiple angles of Plane wave transmissions (PWT) via an ultrasound transducer conveniently give projected Doppler measurements over a wide field of view, providing enough angular diversity to identify velocity vectors in a short time window while capturing transitory flow dynamics. A fast, aliasing-resistant velocity vector estimator for PWT is presented, and VDI imaging of a carotid artery with a 5 MHz linear array is shown using a novel synthetic particle flow visualization method.

An object of disclosed technology is to control lasing wavelengths so that a wavelength shift does not occurs. Another object is to permit wavelengths of a light source for wavelength division multiplexing optical-fiber communication system to be variable in response to an ITU-TS grid. A means for achieving the objects is as follows: locating an etalon in a light path of diode laser light, which is a parallel plane wave changed by a collimator lens; generating a wavelength error signal from a difference between both of divided pieces of light from transmitted light or reflected light; and locking a wavelength of a diode laser device according to the wavelength error signal.

The invention provides a reflection array antenna beam scanning antenna based on a rotation phase shift surface technology. The reflection array antenna beam scanning antenna comprises a feed source antenna (401) and a reflection array panel (301); the reflection array panel (301) comprises a partial wave beam micro-strip reflection array layer (101) and a high transmittance phase shift surface layer (201); the partial wave beam micro-strip reflection array layer (101) is a micro-strip reflection array panel capable of achieving feed source wave beam deflection and the high transmittance phase shift surface layer (201) is a phase shift surface panel capable of achieving plane wave beam deflection. The partial wave beam micro-strip reflection array layer (101) and the high transmittance phase shift surface layer (201) are stacked through certain air space so that the reflection array panel (301) can be assembled. The positive feeding type is adopted by a feed source antenna (401). The central axis of the reflection array panel (301) serves as an axis and two layers are rotated respectively so that scanning of antenna beams can be achieved. The reflection array antenna beam scanning antenna based on the rotation phase shift surface technology is simple in structure, easy to manufacture, capable of responding to any polarized electromagnetic wave, suitable for sending and receiving the polarized electromagnetic waves and capable of bearing high power.

The invention provides a saw tooth structure plane waveguide visual optical display device for enhancing reality. The saw tooth structure plane waveguide visual optical display device for enhancing the reality comprises an image display light source, a collimating lens group, a lengthways expansion structure, a coupling reflection plane, a plane waveguide substrate, a saw tooth grove structure and a prism effect elimination cover piece, wherein the image display light source sends out needed display light waves, the collimating lens group collimates light source light waves, the lengthways expansion structure expands a view field in the vertical direction, the coupling reflection plane couples the light waves after being expanded into the plane waveguide substrate, the plane waveguide substrate transmits the light waves which are coupled into the plane waveguide substrate in total reflection mode, a saw tooth structure is used for view field expansion in the horizontal direction and coupling output of the light waves, and the cover piece is used to eliminate ghost shadows and improve definition of an image. The saw tooth structure plane waveguide visual optical display device for enhancing the reality has the advantages of easily expanding a horizontal view field and the vertical view field, and being light and thin in waveguide, compact in structure, simple in processing technology and low in cost, and not only can be worn for display, but also can be used in fields of scene training simulation, medical ear mirrors, naked eye 3D (three dimensional) display, mobile display and the like.

The invention discloses a millimeter wave folding-type reflective array antenna integrated with a plane feed source. The millimeter wave folding-type reflective array antenna is of a layered structure and is sequentially provided with a polarization grid, a reflective array and the plane feed source from top to bottom. On the basis of a plane substrate integration waveguide structure, a substrate integration waveguide gap array antenna is used as the feed source for conducting feed on folding-type reflection, phase compensation is obtained on a reflection face, spherical waves are converted to plane waves, and therefore the antenna which is high in gain and efficiency and stable in beam pointing is realized. Under the Q-LINKPAN application background and directing at the development demands of a plane-integration and miniaturized long-distance wireless communication system, the low-section antenna which is high in gain and efficiency and capable of being integrated with a plane millimeter wave circuit is realized, the millimeter wave folding-type reflective array antenna has the advantages of being simple in structure, compact in size and low in cost, and the requirements for plane circuit integration are met.