54 results about "Spectral compression" patented technology

The present invention relates to a system and method for providing location determination in a configured environment in which Global Navigation Satellite System Signals are not available. In this regard, local beacon systems generate spread spectrum CDMA signals that are received by spectral compression units that derive physically meaningful observations without a requirement for correlation of the intercepted energy by means of the known spreading codes. The invention can coexist with communication assets already in place, and the design allows for self calibration, which simplifies installation and usage. The invention has utility in applications in which GNSS signals are unavailable or limited, for example, in warehouse inventory management, in search and rescue operations and in asset tracking in indoor environments.

The present invention is a method and apparatus for compressing and decompressing data. In particular, the present invention provides for (de-)compressing naturalistic color-image and moving-image data, including high-precision and high-definition formats, with zero information loss, one-sample latency and in faster than real time on common computing platforms, resulting in doubled transmission, storage, and playback speed and doubled transmission bandwidth and storage capacity, and hence in doubled throughput for non-CPU-bound image-editing tasks in comparison with uncompressed formats. The present invention uses a nearly symmetrical compression-decompression scheme that provides temporal, spatial, and spectral compression, using a reversible condensing / decondensing filter, context reducer, and encoder / decoder. In the preferred embodiment of the invention, the compression filter is implemented as a cascade of quasilinear feedforward filters, with temporal, multidimensional spatial, and spectral stages, where appropriate, in that order, whose support consists of adjacent causal samples of the respective image. The decompressor cascades quasilinear feedback inverse filters in the reverse order. The filters can be implemented with mere integer addition, subtraction, and either one-dimensional table lookup or constant multiplication and binary shifting, depending on the computing environment Tables permit the data precision to be constrained throughout to that of the image samples. The encoder uses a table of prefix codes roughly inversely proportional in length to their probability, while the decoder uses chunked decode tables for accelerated lookup. In the fastest and simplest mode, the code tables are context-independent. For greater power, at the cost of a reduction in speed, the code tables are based on the temporal, multidimensional spatial, and spectral adjacent causal residue samples, where contexts with similar probability distributions are incoherently collapsed by a context reducer using one-dimensional lookup tables followed by implicitly multidimensional lookup tables, to minimize the overall table size. The invention's minimal resource requirements makes it ideal for implementation in either hardware or software.

A method for spectrally compressing data sets enables the efficient analysis of very large multivariate images. The spectral compression algorithm uses a factored representation of the data that can be obtained from Principal Components Analysis or other factorization technique. Furthermore, a block algorithm can be used for performing common operations more efficiently. An image analysis can be performed on the factored representation of the data, using only the most significant factors. The spectral compression algorithm can be combined with a spatial compression algorithm to provide further computational efficiencies.

The present invention relates to a system and method using hybrid spectral compression and cross correlation signal processing of signals of opportunity, which may include Global Navigation Satellite System (GNSS) as well as other wideband energy emissions in GNSS obstructed environments. Combining spectral compression with spread spectrum cross correlation provides unique advantages for positioning and navigation applications including carrier phase observable ambiguity resolution and direct, long-code spread spectrum signal acquisition. Alternatively, the present invention also provides unique advantages for establishing the validity of navigation signals in order to counter the possibilities of electronic attack using spoofing and / or denial methods.

Light pulses can be stopped and stored coherently, with an all-optical process that involves an adiabatic and reversible pulse bandwidth compression occurring entirely in the optical domain. Such a process overcomes the fundamental bandwidth-delay constraint in optics, and can generate arbitrarily small group velocities for light pulses with a given bandwidth, without the use of any coherent or resonant light-matter interactions. This is accomplished only by small refractive index modulations performed at moderate speeds and has applications ranging from quantum communications and computing to coherent all-optical memory devices. A complete time reversal and / or temporal / spectral compression and expansion operation on any electromagnetic field is accomplished using only small refractive index modulations and linear optical elements. This process does not require any nonlinear multi-photon processes such as four-wave mixing and thus can be implemented using on-chip tunable microcavity complexes in photonic crystals. The tuning process requires only small refractive index modulations, and moderate modulation speeds without requiring any high-speed electronic sampling.

The present invention relates to a system and method for positioning and navigation using hybrid spectral compression and cross correlation signal processing of signals of opportunity, which may include Global Navigation Satellite System (GNSS) as well as other wideband energy emissions in GNSS obstructed environments. Examples of these signals of opportunity include but are not limited to GPS, GLONASS, cellular Code Division Multiple Access (CDMA) communications signals, and 802.11 Wi-Fi. Combining spectral compression with spread spectrum cross correlation enables extraction of code and carrier observables without the need to implement the tracking loops (e.g. Costas tracking loop) commonly used in conventional GNSS receivers. For applications where dynamics and transmission medium may make it difficult to continuously track carrier phase, the hybrid approach of the present invention has significant utility.

The present invention relates to a system and method using hybrid spectral compression and cross correlation signal processing of signals of opportunity, which may include Global Navigation Satellite System (GNSS) as well as other wideband energy emissions in GNSS obstructed environments. Combining spectral compression with spread spectrum cross correlation provides unique advantages for positioning and navigation applications including carrier phase observable ambiguity resolution and direct, long-code spread spectrum signal acquisition. Alternatively, the present invention also provides unique advantages for establishing the validity of navigation signals in order to counter the possibilities of electronic attack using spoofing and / or denial methods.

A method for spatially compressing data sets enables the efficient analysis of very large multivariate images. The spatial compression algorithms use a wavelet transformation to map an image into a compressed image containing a smaller number of pixels that retain the original image's information content. Image analysis can then be performed on a compressed data matrix consisting of a reduced number of significant wavelet coefficients. Furthermore, a block algorithm can be used for performing common operations more efficiently. The spatial compression algorithms can be combined with spectral compression algorithms to provide further computational efficiencies.

A speech enhancement system that improves the intelligibility and the perceived quality of processed speech includes a frequency transformer and a spectral compressor. The frequency transformer converts speech signals from the time domain to the frequency domain. The spectral compressor compresses a pre-selected portion of the high frequency band and maps the compressed high frequency band to a lower band limited frequency range. The speech enhancement system may be built into, may be a unitary part of, or may be configured to interface other systems that process audio or high frequency signals.

The invention discloses a hyper-spectral compression imaging method and a system thereof. The method comprises the following steps: carrying out first dispersion after imaging and collimation of an object; focusing an optical signal after dispersion and carrying out space intensity modulation; focusing the modulated optical signal again and carrying out second dispersion; focusing the optical signal after second dispersion, carrying out detection by a detector, carrying out acquisition by a computer, carrying out data resolution, and recovering a three-dimensional data cube of a shot object; wherein the first dispersion and the second dispersion are linear dispersion which are realized by employing a Prism-Grating-Prism device, dispersion directions of the first dispersion and the second dispersion are opposite, and the space intensity modulation is realized by employing a spatial light modulator. According to the invention, data amount is reduced, realization of data resolution of high fidelity is facilitated, and miniaturization design and imaging diversification of an imaging system are facilitated.

The present invention relates to a method for demodulating reference Chirp ultra- wideband system group based on active frequency spectrum compression code which can solve problems of serious ultra-wideband wireless transfers multi-path interference, difficult miniaturisation, poor coexisting performance and low communication distance. The method includes steps as follows: generating a waited-module baseband signal, information bit transmitted in code element period for processing data mould, data by-pass road in code element period and orthogonal code word in reference by-pass processing orthogonal code moulding in data by-pass road and reference by-pass road, processing coalition to the signal in data by-pass and reference by pass with addition, then multiplicating, moulding the multiplicated signal for generating transmitted signal, and transmitting by antennae, processing oblique pulse compressing under condition of gauss white noise, demoulding orthogonal code to the signal, processing multiplication demoulding orthogonal code for the signal compressed by active frequency spectrum with orthogonal code, and processing information judgement to the result. The method is advancedand scientific which can solve efficient communication problem in middle remote distance ultra- wideband system.

A general method for extracting an electromagnetic or other wave-propagated signal of a desired source from the overall received waveform containing the sum of signals from a multitude of such sources, independently of signal contents and modulation. The method comprises the steps of first expanding the spectrum of the received sum of signals in proportion to their source distances so as to spectrally isolate the signal from the desired source, selecting the isolated signal spectrum using a bandpass filter, and finally, spectrally compressing the selected signal back to its original band of frequencies. The distance dependent expansion is performed by scanning the phase gradient of the signal spectrum. Related method for computing the spread of source distances by measuring low and high frequency bounds of the expanded sum of signals or subbands, or by plotting the expanded sum of signals or subbands on a graph.

The invention discloses an SAR imaging quick backward projection method based on image spectrum compression, which comprises the following steps: firstly, performing direction blocking operation on full aperture of a synthetic aperture radar for dividing into N sub-apertures, wherein N is a positive integer; determining a first-stage sub-aperture imaging grid in a rectangular coordinate system, and performing coherent accumulation on an echo signal s(x,r) after a distance pulse pressure by means of a projection algorithm BPA, thereby obtaining N sub-aperture rough images of first-grade sub-apertures; in the rectangular coordinate system, performing directional frequency spectrum compression on the N sub-aperture rough images of the first-grade sub-apertures; then setting direction interval and distance interval of a next-grade sub-aperture imaging grid, performing coherent accumulation to the N sub-aperture coarse images of the first-grade sub-apertures after directional frequency spectrum compression successively in a paired manner, obtaining the sub-aperture coarse image of a next-grade sub-apertures; and finally, performing directional frequency spectrum compression and coherent accumulation for finally obtaining a full-aperture image.

The invention discloses a hyper-spectral compression perception reconstruction method based on nonlocal total variation and low-rank sparsity, and mainly solves the problems in the prior art that reconstruction accuracy is low and the effect is poor after compressed sampling of hyper-spectral data. The hyper-spectral compression perception reconstruction method comprises the steps that 1. the hyper-spectral data are inputted and vectorized; 2. the vectorized hyper-spectral data are sampled so that sampling data are obtained; 3. initial reconstruction of the sampling data is performed; 4. the initially reconstructed data are clustered; 5. the sampling data are classified according to the type of image elements so that various types of sampling data are obtained; 6. a secondary reconstruction model is constructed; and 7. The secondary reconstruction model is solved according to various types of sampling data so that the optimal data of secondary reconstruction are obtained, and the data act as the final reconstruction data. The idea of nonlocal total variation and clustering is introduced on the basis of low-rank sparse reconstruction so that the hyper-spectral compression perception reconstruction method has advantages of high reconstruction accuracy and great effect and can be used for hyper-spectral data imaging.

The invention discloses a portable high-resolution optical fiber CARS microscopic excitation source device and an implementation method. The device sequentially comprises a femtosecond optical fiber laser light source (1), a beam splitter (2), an electronically-controlled phase delayer (3), an analyzer (4), a photonic crystal fiber (5), a multimode fiber (6), a single mode fiber (7), an electronically-controlled delay line (8), a beam combiner (9), an output port (11) and a control module (10) according to the sequence from input to output. The portable high-resolution optical fiber CARS microscopic excitation source device has the advantages that the optical fiber structure is adopted, environment anti-interference performance is high, and the device is portable and has the ability to be quickly connected with a commercialized microscope to enable a CARS imaging function to be achieved; chirp processing can be carried out on pulsed light by means of the combined optical fiber structure, the stable and reliable spectral compression is achieved, and the spectral resolution is improved.

The present invention provides a system, apparatus, and method for efficient optical amplification and transmission of a data-encoded optical signal within a networking device, such as a transmitter or receiver. In various embodiments of the invention, an optical duobinary signal or hybrid duobinary signal is generated and shaped in preparation for amplification of the optical signal by an SOA. The deleterious impact of SOA fast gain dynamics may be reduced by taking advantage of characteristics of a duobinary or hybrid duobinary signal (e.g., a relatively lower pulse amplitude and no phase encoded data) and shaping the optical duobinary pulse (e.g., smoothing amplitude swings within the signal and spectral compression).

An algorithm calculates spectral compression / expansion filter coefficients using a value proportional to a reciprocal of a feedback / feedforward signal and stores the coefficients to a lookup table. The lookup table is indexed by a pre-selected set of coefficient bits to generate a filter coefficient function. A first portion of the lookup table stores a plurality of discrete values at index points of a line segment corresponding to a filter coefficient function approximation, so as to generate an initial discrete value corresponding to the filter coefficient function at a value of the high order bits and a second portion stores a plurality of slope values, which indicates a slope of the filter coefficient function. A linear circuit interpolates / decimates an approximation of the compression / expansion filter coefficient function based on the slope value, the initial discrete value and a preselected set of low order bits of the reciprocal value.

Light pulses can be stopped and stored coherently, with an all-optical process that involves an adiabatic and reversible pulse bandwidth compression occurring entirely in the optical domain. Such a process overcomes the fundamental bandwidth-delay constraint in optics, and can generate arbitrarily small group velocities for light pulses with a given bandwidth, without the use of any coherent or resonant light-matter interactions. This is accomplished only by small refractive index modulations performed at moderate speeds and has applications ranging from quantum communications and computing to coherent all-optical memory devices. A complete time reversal and / or temporal / spectral compression and expansion operation on any electromagnetic field is accomplished using only small refractive index modulations and linear optical elements. This process does not require any nonlinear multi-photon processes such as four-wave mixing and thus can be implemented using on-chip tunable microcavity complexes in photonic crystals. The tuning process requires only small refractive index modulations, and moderate modulation speeds without requiring any high-speed electronic sampling.

The invention provides an efficient frequency-division multiplexing waveform generation method based on zero-trailing DFT extension, and belongs to the technical field of the information and communication. The efficient frequency-division multiplexing waveform is high in spectrum effect, low in out-of-band leakage and low in peak-to-average ratio. The method comprises the following steps: step one, performing zero-filling on the head and tail of a sending end modulation symbol to acquire a time domain sending symbol sequence, performing DFT extension transform of N points on the time domain sending symbol sequence to obtain a frequency domain signal vector; step two, filing (1-a)N / a zeros at the tail of the obtained frequency domain signal vector, and performing sub-carrier mapping on the zero-filled frequency domain signal vector; and step three, performing IFFT transform of K points on the signal vector after the sub-carrier mapping, abandoning last (1-a)N / a data of the acquired frequency domain signal vector after the transformation, wherein the rest N data is the time domain sending symbol vector with the zero-trailing feature, and the formed waveform is the generated efficient frequency-division multiplexing waveform; a represents the spectrum compression factor, and a is equal to N / K.

A general method for extracting an electromagnetic or other wave-propagated signal of a desired source from the overall received waveform containing the sum of signals from a multitude of such sources, independently of signal contents and modulation. The method comprises the steps of first expanding the spectrum of the received sum of signals in proportion to their source distances so as to spectrally isolate the signal from the desired source, selecting the isolated signal spectrum using a bandpass filter, and finally, spectrally compressing the selected signal back to its original band of frequencies. The distance dependent expansion is performed by scanning the phase gradient of the signal spectrum. Related method for computing the spread of source distances by measuring low and high frequency bounds of the expanded sum of signals or subbands, or by plotting the expanded sum of signals or subbands on a graph.

The invention discloses a polarization and hyper-spectral compression imaging method and system. The polarization and hyper-spectral compression imaging system is provided with an objective lens, a polarization modulator, a collimating lens, a first linear dispersion device, a first convex lens, a spatial modulation mask plate, a second convex lens, a second linear dispersion device, a lens and adetector in sequence along the direction of light transmission, wherein the objective lens is used for imaging a target on the polarization modulator. The polarization and hyper-spectral compression imaging method comprises the following steps: imaging the target on the polarization modulator, collimating the emergent light, carrying out first dispersion on the collimated emergent light, carryingout spatial modulation on the dispersed light signal, carrying out second dispersion, projecting the light on the detector, collecting data by using a computer, completing data calculation, and restoring four-dimensional data information of the target. The invention realizes the hyper-spectral instantaneous compression imaging of three-dimensional data cubes in a certain vision field under the control of polarization modulation, greatly reduces the quantity of data received by the detector, improves the signal-to-noise ratio of the system and is especially beneficial to the target imaging of weak light intensity and strong dispersion.

The invention relates to a fast BP imaging method for a parallel double-base spotlight mode SAR, comprising the following steps: acquiring full aperture echo data of the parallel double-base spotlightmode SAR; dividing the full aperture data into a plurality of non-overlapping subaperture data blocks, projecting the subaperture data after distance compression to a global rectangular coordinate system by using a double-base BP integration, and obtaining an initial resolution image of a first-stage subaperture; compressing the subaperture image spectrum by using a spectral compression function;performing azimuth multiple upsampling on compressed data; restoring the original signal form of the subaperture image by using the conjugated form of the spectral compression function; performing coherent superposition on the restored subaperture image to obtain a subaperture image with improved resolution; repeating the step S30 to S60 for the image with improved resolution until a full resolution image is obtained. Compared with an imaging algorithm, the fast BP imaging method for a parallel double-base spotlight mode SAR has the advantages that a high-quality image can be obtained, the calculation amount is greatly reduced, and the operation efficiency is further improved.

A normalized frequency spectrum compression-based long focal length focusing lens is disclosed and is used for realizing ultra long focal length focusing focal spots via compression of Fourier frequency spectrum of a focusing device relative to spatial cut off frequency. The lens has an annular metal-medium structure, auxiliary design wavelength and auxiliary design focal length are calculated, amplitude distribution and phase distribution of the lens are optimized, ultra diffraction focusing of ultra long focal length is realized, and transverse dimensions of the focal spots are enabled to besmaller than diffraction limits in a scope in which focal depth is greater than 100 time wavelength. Via use of the lens disclosed in the invention, design complexity and a calculation quantity of ultra long focal length long focal length and ultra diffraction lenses can be greatly reduced, and difficult problems that ultra long focal length and ultra diffraction focal spots are hard to realizedvia a conventional lens design method can be solved. The focusing lens is great in application prospects in the fields of particle control, super-resolution optical microscopy, high density data storage and the like. Besides an optical wave band, the use of the lens can also be expanded to other wave bands of electromagnetic waves; the lens disclosed in the invention can be widely applied to design and realization of electromagnetic wave function devices.

The invention provides a center-symmetric acoustic vector circular array fast spatial spectral compression super-resolution orientation estimation method. The method comprises the steps that sensors on the upper and lower half rings of an acoustic vector circular array are arranged in a specific order respectively, and acoustic signals are collected to construct a satisfactory steering vector; then based on the average sound intensity anti-noise principle of acoustic vector sensors, a covariance matrix is constructed by using the method of combined processing of sound pressure and vibration velocity, which reduces the dimension of a vector matrix steering vector matrix and improves the anti-noise ability; a new spatial spectrum function is constructed from the spatial spectrum of a real source and a virtual source 180-degree away from the real source to carry out half-spectral search to compress the spatial spectrum of the acoustic vector circular array; and finally, through the discriminant constructed in the invention, the true sound source orientation is quickly determined. According to the invention, the spatial spectrum of the vector circular array is compressed for the firsttime, which greatly improves the operation efficiency while ensuring high resolution; and fast and efficient super-resolution orientation estimation of the acoustic vector circular array is realized.

The invention relates to a robust speech recognition method and system based on speech enhancement and improved PNSC. Speech signals are obtained through a microphone, speech enhancement and feature extraction are carried out on the speech signals after the speech signals are preprocessed, and in a signal space, enhancement is carried out by means of a speech enhancement algorithm combining the auditory masking effect and a priori signal-to-noise ratio; in a feature space, feature values of the speech signals are extracted more accurately by means of a feature extraction algorithm improving perception non-uniform spectral compression, the speech signals are trained and recognized through a dynamic time wrapping algorithm, a speech recognition result is converted into a bottom layer drive instruction of an intelligent wheelchair, a corresponding control function is called, and the intelligent wheelchair is driven to move according to the speech signals. By means of the method and system, the recognition rate of the system in a noise environment is increased, precise control over the intelligent wheelchair is achieved, the aim of achieving speech interaction between a user and the intelligent wheelchair is achieved, and the method has good universality in a specific human speech recognition system.