15 results about "Near field imaging" patented technology

The invention discloses a multi-mode nanometer measurement system and method based on terahertz scattering type scanning near-field optical microscopy and multi-frequency electrostatic force microscopy, and belongs to the technical field of near-field imaging, the measurement system comprises an AFM main body, a terahertz source, an optical path system, a terahertz detector, a multi-frequency signal generator and two phase-locked amplifiers; terahertz waves emitted by the terahertz source reach the terahertz detector through the optical path system, and near-field optical signals are obtained. The AFM comprises a metal coating probe; the multi-frequency signal generator generates sinusoidal signals with frequencies of omega1 and omega2; a sample is placed on the scanner, and the cantilever beam is controlled to vibrate at the frequency omega 1; an alternating voltage with the frequency of omega 2 is applied to a metal coating probe arranged at the top end of the cantilever beam; laser emitted by the laser is reflected to the light spot position detector through the cantilever beam, and morphology and electrostatic force signals are obtained through the two lock-in amplifiers respectively. According to the invention, a morphology signal, an optical signal and an electrostatic force signal can be synchronously obtained through single scanning.

Various embodiments described herein provide for multi-projector (i.e., two or more) imaging devices that utilize an integrated illuminator-sight optic. Embodiments of the present disclosure minimize misalignment of non-repairable components to improve overall accuracy associated with operation of the device. Additionally, the integrated illuminator-sight optic enables embodiments disclosed herein to be disposed in a significantly smaller form factor than conventional multi-projector imaging devices. An exemplary device includes: a near field imaging lens and a far field imaging lens; an integrated illuminator-sight optic positioned between the near field imaging lens and the far field imaging lens; a near field illuminator source and a far field illuminator source positioned for projection via the integrated illuminator-sight optic; a near field imaging sensor associated with the near field imaging lens; a far field imaging sensor associated with the far field imaging lens; and a device chassis for aligning the various components for operation.

An s-SNOM subsurface defect fine imaging method and system based on polarization laser scattering guidance belong to the technical field of optical nondestructive testing, and are realized based on a laser, a polarizer, a polarization modulator, a sample to be tested, an optical splitter array, an analyzer array and a detector which are sequentially arranged along the laser propagation direction, and the sample to be tested comprises subsurface defects. Firstly, a to-be-detected sample is subjected to polarization scattering rapid detection to obtain polarization scattering data; secondly, performing quantitative analysis and risk assessment on the non-uniformity of the subsurface structure to obtain a region of interest; thirdly, performing region-of-interest extraction and detection task scheduling on the high-risk region; and finally, performing high-resolution near-field scanning imaging on the region of interest. On the basis of keeping the advantage of s-SNOM high-resolution imaging, cross-scale cooperation between polarization scattering information and near-field imaging can be realized by introducing a rapid and effective prior guiding mechanism, and efficiency and precision are both considered in large-area sample detection.

The invention specifically relates to a rapid three-dimensional near-field imaging method based on a millimeter wave MIMO antenna array system, and the method comprises the steps: selecting a scene center as a reference point in a first stage, and carrying out the conversion from multiple stations to a single station; then, a coarse imaging result of the whole scene is generated by applying 3D-RMA; in the second stage, the imaging scene is divided into blocks, and fine imaging results of all target positions are obtained by applying a 2D-RMA slicing algorithm with fast calculation for several times. The invention aims to solve the problems that the storage burden of high-dimensional data is reduced, the imaging quality is ensured, the calculation complexity is greatly reduced, the approximate error of a reference point is eliminated, the problem of near-field defocusing caused by far-field hypothesis failure is solved, and the near-field three-dimensional real-time focusing imaging is realized.

The application provides a wave band splicing terahertz near field imaging system and method based on a frequency selective surface, which comprises a terahertz spread spectrum module, a first combination module, a parabolic mirror and a near field probe.The terahertz spread spectrum module is used for generating a terahertz signal and receiving a reflection signal of a near field terahertz signal of a sample to be measured.The first combination module is used for combining the terahertz signal generated by the terahertz spread spectrum module and converging to the parabolic mirror.The parabolic mirror is used for collecting the terahertz signal incident on the frequency selective surface and converging to the tip of the near field probe.The near field probe is used for modulating the terahertz signal by exciting the terahertz signal in the vertical direction to obtain the near field terahertz signal and reflecting the near field terahertz signal to the terahertz spread spectrum module.The reflection signal of the near field terahertz signal is the same as the light path of the incident terahertz signal.The application can realize terahertz near field imaging test in a wide band range by using the multi-wave band splicing terahertz near field imaging test technology based on the frequency selective surface.

The application relates to the technical field of fast near-field imaging, in particular to a quadrilateral MIMO array fast near-field imaging method based on a GPU, which comprises the following steps: a host end issues control instructions and parameters to a high-speed signal processing board carrying an FPGA, an FPGA drives a frequency synthesizer module to generate a local oscillation signal and distributes the local oscillation signal to a quadrilateral MIMO array; the FPGA controls T / R radio frequency front-end devices, sequentially completes scanning operation of multichannel transmission and reception in a time division multiplexing mode, an ADC samples and converts collected echo signals into digital signals, and then the digital signals are transmitted to a GPU; a parallel imaging architecture is constructed in the GPU, and the whole imaging task is decomposed into several independent sub-imaging tasks; after the current sub-imaging task is completed, the current sub-image is superimposed with the last sub-image, until all the sub-imaging tasks are completed, three-dimensional imaging results of the whole imaging area are obtained, and the three-dimensional imaging results are returned to the host end for display.

A probe useful for introducing therapeutic materials between the neural sheath and contained neurovascular tissue provides a near field imaging device permitting final positioning of the probe to be conducted with submillimeter accuracy and a vacuum channel allowing the probe to be attached to the neural sheath to withdraw it and provide a defect through which therapeutic agents can be introduced.

The application relates to a high-repetition-frequency strong-field terahertz coupling near-field imaging system, and belongs to the technical field of terahertz time-domain spectroscopy. The system solves the problem of low terahertz source power and single-pulse energy in a near-field probe scanning system in the prior art, and comprises a femtosecond laser light source (1) for providing femtosecond pump laser; a non-polarized beam splitter (3) for splitting the pump laser provided by the femtosecond laser light source (1) into two beams, which are respectively provided to the light path of the pump laser and the light path of detection light, and converting one of the pump lasers into terahertz radiation through the light path of the pump laser; and a sample scanning module comprising a terahertz near-field probe (20) for receiving the terahertz radiation to perform terahertz scanning and imaging on a sample surface.

A device comprising an image sensor for capturing a stream of asynchronous data representing per-pixel changes in radiance within a scene over an acquisition cycle and processing circuitry communicatively coupled to at least one light source positioned to illuminate at least an area of the scene, the processing circuitry configured to modulate output of the at least one light source over the acquisition cycle.

This invention discloses a sparse near-field SAR imaging method based on high-order total variation with multiple constraint exponents, belonging to the field of radar imaging technology. The method includes the following steps: S1, sampling the scene and preprocessing the scene echo data; S2, calculating the NFCS approximate observation operator; S3, constructing a hybrid sparse near-field SAR imaging model; S4, initializing the parameters of the hybrid sparse near-field SAR imaging model and the NFCS approximate observation operator; S5, updating the hybrid sparse near-field SAR imaging model to complete hybrid constraint sparse near-field SAR imaging; and S6, outputting the imaging results. The method proposed in this invention can accurately reconstruct the target scattering intensity amplitude information, avoiding the underestimation of target scattering point intensity by L1 regularization, while also suppressing speckle noise and avoiding artifacts. It takes into account both the sparsity of the target and the differences in target scattering intensity, improving the imaging performance of complex scenes.

A device comprising an image sensor for capturing a stream of asynchronous data representing per-pixel changes in radiance within a scene over an acquisition cycle and processing circuitry communicatively coupled to at least one light source positioned to illuminate at least an area of the scene, the processing circuitry configured to modulate output of the at least one light source over the acquisition cycle.

This invention belongs to the field of radar imaging technology, specifically relating to a near-field BP imaging method based on antenna pattern gain compensation. The specific process is as follows: Step 1, measure the actual antenna pattern under anechoic conditions; Step 2, calculate the pixel value of any point in the imaging area based on the BP imaging method; Step 3, calculate the angle between any pixel in the imaging area and the transmitting and receiving antennas; Step 4, based on the measured antenna pattern and the angle between the antenna and the pixel, calculate the actual gain obtained from radar echoes from different directions in each channel, i.e., the actual gain obtained by the transmitting and receiving antennas; Step 5: Construct a gain compensation matrix using the actual gains obtained by each transmitting and receiving antenna, and use the gain compensation matrix to compensate for each pixel in the imaging area.

The application discloses a s-SNOM sub-surface defect fine imaging method and system based on polarization laser scattering guidance, belongs to the technical field of optical nondestructive testing, and is realized based on a laser, a polarizer, a polarization modulator, a to-be-detected sample, a light splitter array, a polarimeter array and a detector which are sequentially arranged along a laser propagation direction, and the to-be-detected sample contains a sub-surface defect. Firstly, polarization scattering fast detection is carried out on the to-be-detected sample to obtain polarization scattering data; secondly, quantitative analysis and risk assessment are carried out on sub-surface structure non-uniformity to obtain a region of interest; thirdly, region of interest extraction and detection task scheduling are carried out on a high-risk region; and finally, high-resolution near-field scanning imaging is carried out on the region of interest. On the basis of maintaining the high-resolution imaging advantage of the s-SNOM, the prior guidance mechanism is introduced, cross-scale cooperation between polarization scattering information and near-field imaging can be realized, and efficiency and precision are taken into account in large-area sample detection.

This invention discloses a terahertz autocorrelation near-field imaging spectroscopy system, relating to the interdisciplinary field of micro-nano photonics and terahertz photoelectric detection. The system includes: a terahertz emitter, an optical path adjustment unit, a scattering near-field scanning microscope, a terahertz receiver, a current amplifier, a lock-in amplifier, and a processor. This invention employs autocorrelation near-field imaging spectroscopy, which can obtain the time-domain information of terahertz waves by performing autocorrelation measurements on terahertz pulses. The autocorrelation near-field imaging spectroscopy method in this invention also has the ability to enhance signal intensity and suppress background noise. By controlling the optical path difference and adjusting the optical path, the two signals are accumulated to achieve a modulation of the probe resonance effect, which is beneficial for studying the resonance characteristics of the sample itself.

The embodiment of the invention provides a near-field sparse antenna array arrangement and signal joint optimization method, device and equipment. The method comprises the following steps: firstly, according to a transmitting antenna array, a receiving antenna array and a to-be-imaged area, constructing an analytic expression relationship between a relative error and an equivalent channel matrix condition number in a near-field imaging system; then, on the basis of the analytic expression relation, a joint optimization problem with the purpose of minimizing the equivalent channel matrix condition number is constructed; then solving a joint optimization problem to obtain the arrangement position of the optimized antenna array and the optimized transmitting signal parameters; and finally, according to the optimized arrangement position of the antenna array and the optimized emission signal parameters, determining the antenna array arrangement and emission signal parameters of the near-field imaging system. Through the method, the near-field imaging quality is enhanced.