155 results about "Near and far field" patented technology

An apparatus and method of reproducing a 2-channel virtual sound while dynamically controlling a sweet spot and crosstalk cancellation are disclosed. The method includes: receiving broadband signals, setting compensation filter coefficients according to response characteristics of bands and setting stereophonic transfer functions according to spectrum analysis; down mixing an input multi-channel signal into two channel signals by adding head related transfer functions (HRTFs) measured in a near-field and a far-field to the input multi-channel signal, canceling crosstalk of the down mixed signals on the basis of compensation filter coefficients calculated using the set stereophonic transfer functions, and compensating levels and phases of the crosstalk cancelled signals on the basis of the set compensation filter coefficients for each of the bands.

An imaging system and method are presented. The system comprises an imaging lens unit, an imaging detector, and a birefringent element located between the imaging lens unit and the imaging detector. The system is thus configure and operable to provide in-focus imaging of objects located at both near-field and far-field ranges. Also provided is an optical device configured to be mounted on an imaging lens, being one of the following: a lens of an individual's glasses, on a contact lens, and an eye internal lens. The optical device is configured to be located between the imaging lens and the retina and comprises a birefringent element, to thereby provide in-focus imaging onto the retina of the objects located at both near-field and far-field ranges therefrom.

Radio frequency identification (RFID) devices for use in RFID-based sensors and related methods are described herein. In one implementation, an RFID sensor system includes an RFID device having a near field only RFID tag and a conductive element which functions as a far field antenna. A coupling structure selectively locates the near field only RFID tag and the conductive element in at least a first position and a second position relative to each other; wherein in the first position, the RFID device only operates in a near field, and in the second position, the RFID device operates in both the near field and a far field. The system may also include an RFID reader and controller located within the far field to read the RFID device only when the coupling structure locates the components in the second position.

The invention relates to an apparatus for skin imaging, a system for skin analysis and a method for skin analysis, using a combination of near-field and far-field skin images under different angles of illumination. The apparatus provides a tool that may be employed for rapid screening of the skin for lesions that may be indicative of skin diseases, in particular skin cancers such as melanoma.

The invention discloses a light path collimation integrated device and method for a high-power laser device. A transmission grating engraved with references is put near to the small-hole face of a space filter; the transmission grating is irradiated by parallel non-coherent illumination lights produced by a light emitting diode and an illumination collimation lens at a specific angle; a sampling light path is put in a direction of first-stage diffraction light of the transmission grating so as to form a light beam information monitor; the light beam information monitor simultaneously acquiresinformation of a near field and a far field of a light beam; the output of the light beam information monitor is connected to a computer; deviation values of the near field and far field of the lightbeam relative to the respective set positions are determined through an image processing technology; and a corresponding near field adjusting device and a corresponding far field adjusting device areselected according to the respective deviation values so as to adjust light path collimation. The light path collimation integrated device has the characteristics of integration, modularization, simple structure and high precision, and can meet a monitoring requirement of the high-power laser device on large-aperture light beam collimation.

The invention discloses a multi-channel optical-fiber laser coherence beam combination device and a coherence beam combination method based on overlapped body grating. The device comprises an optical-fiber coupler, a doping double-clad optical-fiber, a lens, a dichroiscope, a reflector, a polarization controller, a reflector, an overlapped body grating and an output coupling mirror connected in sequence at one side of the optical-fiber grating. The method is able to realize the multi-channel optical-fiber laser coherence beam combination without complex phase detection and control to each beam. The phases of each beam realize interlocking by sharing a resonator composed of the output coupling mirror and the optical-fiber grating. Each beam realizes the coherent superposition in the near-field and far-field to significantly enhance the output power and the brightness of the optical-fiber laser through the overlapped body of grating. The invention features the simple structure and complex structure without increasing as the increase of the beam combination laser, and is able to be widely applied in the field needing the large power optical-fiber laser as the light source, thereby capable of gaining the large power, high beam quality as well as compact high-energy laser system.

The invention provides a multi-target near-and-far field mixed source positioning method and belongs to the field of the array signal processing technology. According to the method, firstly, a symmetric and homogeneous linear sensor array is arranged to receive a target signal, and then the observation signal form of a near-and-far field mixed source is determined. Secondly, a special third-order cyclic matrix is constructed based on the output of a properly selected sensor, and a direction matrix thereof only contains the azimuth information of a far-field source and the azimuth information of a near-field source. Thirdly, the eigenvalue of the third-order cyclic matrix is decomposed, so that a corresponding noise sub-space is obtained. Fourthly, a cyclic autocorrelation matrix based on the observation data of the entire matrix is calculated, and the eigenvalue of the cyclic autocorrelation matrix is decomposed. In this way, a corresponding noise sub-space is obtained. Fifthly, an already estimated azimuth is substituted to the two-dimensional MUSIC spectrum peak searching process, so that the estimation on the distance of the near-field source is realized. The application of four-order cumulants is avoided, and the calculation complexity of the algorithm is effectively reduced. The operation time of the algorithm is shortened. Meanwhile, the cyclic steady interference and the steady background noise are effectively suppressed. Moreover, the extra parameter matching process is avoided.

An audio headset may comprise a case, near field microphone and far field microphone. A speaker, processor, memory, battery, charging interface and cradle detection circuit may be mounted to the case. Processor-executable instructions embodied in the memory, may be configured to implement a battery charging method. The headset may be shut off in response to placement of the headset in a charging cradle. The far-field microphone is turned on but not the near-field microphone. The battery may then be charged from the cradle. A headset having near-field and far-field microphones may be used to distinguish between user speech and competing sounds by generating signals from the sounds detected by each microphone and comparing the strengths of the signals. The signals may be processed as user speech if they are of comparable strength. Otherwise, the near-field signal may be processed as user speech and the far-field signal as competing sounds.

Radio frequency identification (RFID) devices, and methods of manufacture are described herein. In one implementation, an RFID device comprises a near field only RFID tag that does not function as a far field RFID tag and is pre-manufactured; and a conductive element independent from the near field only RFID tag and configured to function as a far field antenna, wherein the conductive element extends a length and includes a central region and includes at least one distal region defining a voltage end of the conductive element. The near field only RFID tag and a distal region of the conductive element are coupled in proximity to each other such that the RFID device functions in both a near field and a far field.

A lens position sensor for infrared or other types of cameras, which is particularly useful in lens assemblies that have relatively limited axial travel between near field and far field lens focus positions. The camera includes a magnet or other stimulator coupled to a rotatable lens that extends within a magnet plane where the magnet plane is not normal to the optical axis of the lens. A magnetic or other sensor senses the position of the magnet, which is indicative of the lens position.

The invention discloses a large-scale antenna field directional diagram measuring system and method for multi-rotor unmanned aerial vehicles. The system includes a multi-rotor unmanned aerial vehiclesubsystem, a signal source link subsystem, a receiving link subsystem and a data processing subsystem. A multi-rotor unmanned aerial vehicle is used to fly at near and far field areas of a to-be-measured antenna according to a set cruise mission; through remote real-time control on a signal source link module, an electromagnetic wave signal in the air can be swept and received in real time; and through the screening, error compensation and data fitting on a received level signal, final directional diagram information can be generated, and the maximum radiation direction, 3dB lobe width, sidelobe level, front-to-back ratios and corresponding position information can be given. On-the-spot directional diagram performance measuring of large-scale antennas under service status can be realized,so that accurate measured data can be provided for fault diagnosis; the system is convenient in operation, high in degree of automation and simple in dismounting; and single sortie flight can accomplish the testing of multifrequency directional diagrams.

The invention provides a comprehensive real-time calibration method for a multi-channel digital anti-interference antenna system, which can effectively increase output signal to noise ratio of the system. The method is implemented by the following technical scheme and comprises the following steps: connecting an antenna array surface, channels and a signal processing plate between a power supply and a computer to form a self-calibration antenna system; transmitting a near-field signal and a far-field signal by using a transmitting antenna and a standard antenna at different time, calculating difference between amplitude and phase of two groups of signals output by a receiving channel and storing the difference value into FLASH; controlling the channels and the signal processing plate by using a computer through a serial port so as to be in a calibration state and performing system calibration by comparing the amplitude and the phase of the signal of each channel by a calibration algorithm stored in a field programmable gate array (FPGA); and providing analog inertial navigation information to the signal processing plate by using the computer through the serial port, automatically adjusting the main beam of the antenna according to the inertial navigation information by an anti-interference algorithm in the FPGA, and inhibiting the antenna to receive each external interference signal. According to the method, high efficiency and sustainability of system operation are guaranteed.

This invention relates to devices and processes for geophysical prospecting, subsurface fluid monitoring and, more particular, to the use of interferometric techniques using Control Source Electromagnetic (“CSEM”) and Magnetoturelic (“MT”) signals to create images of sub-surface structures and fluids.