50 results about "Hadamard code" patented technology

A highly bandwidth-efficient communications method is disclosed that enables remote stations to synchronize in time and frequency to their serving base station. The invention enables a base station and its remote stations in a cell to synchronize in a noisy environment where signals interfere from other base stations and remote stations in other cells. The base station forms a forward synchronization burst that includes a plurality of tone frequencies arranged in a distinctive orthogonal frequency division multiplexed pattern unique to the base station. The unique pattern enables a remote station to distinguish the base station's bursts from other signals present in a crowded area. The distinctive orthogonal frequency division multiplexed pattern can be a Hadamard code pattern, for example. When the a base station has received a signal on a reverse link from a remote station, having significant interference, the base station selectively forms a request signal requesting the remote station to respond with a reverse synchronization burst that includes a plurality of tone frequencies arranged in the same distinctive orthogonal frequency division multiplexed pattern. The base station then transmits the forward synchronization burst and the request signal at a base station reference instant of time to the remote station. The reverse synchronization signals selectively occupy time slots in the transmission frame from the remote station to the base station, that would otherwise be occupied by channel control or traffic signals. Only when the base station requests the remote station to respond with a reverse synchronization burst, does this burst preempt the time slot from its other uses.

A system and methods are provided for imaging an object, based on activating an array of discrete X-ray sources in a prescribed temporal pattern so as to illuminate the object with a beam varying in spatial orientation, and detecting X-rays of the beam after interaction with the object and generating a detector signal. An image of the object may then be constructed on the basis of the time variation of the detector signal. The discrete X-ray sources may be moved during the course of inspection, moreover, the prescribed temporal pattern may constitute a Hadamard code. The discrete sources may be carbon nanotube x-ray sources.

In one embodiment, a Walsh-Hadamard decoder can have a hardware efficient Fast Hadamard Transform (“FHT”) engine. In one embodiment, the FHT engine can include an input to receive an input sequence to be decoded into a Walsh-Hadamard codeword. The FHT engine can further include a controller to correlate the received input sequence with a plurality of Walsh-Hadamard codewords using two add / subtract modules. In one embodiment, the two add / subtract modules operate in parallel.

The invention discloses a large-visual-field high-resolution microscopic imaging method based on optimal Hadamard codes. The large-visual-field high-resolution microscopic imaging method includes generating a required optimal Hadamard code matrix by a computer, taking an LED array as a microscope light source, displaying optimal Hadamard code patterns, shooting a series of low-resolution microscopic images of a to-be-tested sample at different illumination angles by a camera, solving the low-resolution microscopic image of the to-be-tested sample under single-angle illumination according to the optimal Hadamard code matrix, and compositing the large-visual-field low-resolution microscopic images into a large-visual-field high-resolution image by the aid of a frequency domain aperture synthesis technology. The large-visual-field high-resolution microscopic imaging method has the advantages that required exposure time of the camera can be shortened, system image collection speed can be increased, noise can be suppressed, and quality of image collected by a system can be improved.

An encoder includes an outer repetition encoder, an interleaver for permuting encoding from said outer repetition encoder; and an inner encoder for encoding information from the interleaver to provide a repeat zigzag-Hadamard code. In an exemplary embodiment, a common bit of a zigzag-Hadamard segment of encoding from said inner encoder is a repetition of a last parity bit of a previous zigzag-Hadamard segment of encoding from said inner encoder and said common bit is punctured.

The invention relates to a hadamard transform imaging spectrometer based on a bridge type grating light modulator, and the spectrometer provided by the invention can be applied to a linear array detector or single point detector. The hadamard transform imaging spectrometer comprises a receiving optical system, a chromatic dispersion element, an imaging mirror, a bridge type grating light modulator array, a focusing mirror and a detector, wherein the radiation information of a target is imaged on the chromatic dispersion element in lines by the receiving optical system according to different time sequences; after being split by the chromatic dispersion element, the radiation information is imaged on the programmable bridge type grating light modulator array by the imaging mirror; the bridge type grating light modulator array is programmed and driven according to a hadamard coding template, thereby allowing lights with different wavelengths to pass through in a manner of specific combination; the lights are focused on the detector by the focusing mirror; and finally, the space dimensional information and spectrum dimensional information of the target are acquired by performing the hadamard inverse transformation. The hadamard transform imaging spectrometer has the advantages of small volume, light weight, low cost, high speed and high signal to noise ratio. The hadamard transform imaging spectrometer can be widely applied to the fields of aerial remote sensing, industry, agriculture, biomedicine, matter analysis and classification, universal and astronomic surveillance, environment and disaster monitoring, atmospheric detection, searching and tracking for military targets, and the like.

Disclosed herein is a method of driving a touch panel having driving lines, sensing lines, and node capacitors between neighboring driving lines and sensing lines. The method includes pairing two neighboring driving lines, setting the pairs such that each of the pairs is driven using driving signals having an opposite phase, shuffling positions of the pairs so that at least one set of neighboring pairs includes different driving lines, classifying or combining at least two shuffled pairs into one group, generating Hadamard codes based on the pairs in each group, and simultaneously driving the driving lines in each of the generated Hadamard codes.

The invention provides a low density parity code (LDPC)-Hadamard code-assisted iteration carrier synchronization scheme, which can realize accurate synchronization and correct decoding even under the condition of extremely low signal to noise ratio. In the scheme, two modules, namely a LDPC-Hadamard code decoder and a carrier synchronizer are provided, wherein the carrier synchronizer estimates frequency offset and phase offset by using soft information output by the decoder, performs carrier compensation on a received signal by using estimated values of the frequency offset and the phase offset, transmits a compensated signal to the decoder for decoding and outputs soft information. After iteration is performed repeatedly, carrier synchronization and LDPC-Hadamard code decoding can be realized at the same time. The biggest advantage of the scheme is that: a low-bit-rate code (an LDPC-Hadamard code) is taken as an error correcting code, so that accurate carrier synchronization and correct decoding can be realized under the condition of extremely low signal to noise ratio. A coding and decoding structure of the LDPC-Hadamard code is mainly introduced, and an LDPC-Hadamard code-assisted iteration carrier synchronization method is provided in combination with the decoding structure of the LDPC-Hadamard code. At last, an embodiment is given.

A method for selecting a signal to noise ratio for a communications code includes obtaining extrinsic information transfer (EXIT) information for a repeat-zigzag Hadamard (RZH) code responsive to a Hadamard order and a signal to noise ratio, determining code parameters for an irregular repeat zigzag Hadamard (IRZH) code for a corresponding code rate in response to the obtained EXIT values, and repeating the step of obtaining the EXIT information for a different signal to noise ratio if the corresponding code rate is other than a selected rate. The corresponding code rate is related to a bit error rate. In a preferred embodiment, the step of obtaining EXIT information includes one of obtaining an EXIT curve for repeat-zigzag Hadamard code by Monte Carlo simulation using serial decoding or obtaining an EXIT function for parallel decoding of the repeat-zigzag Hadamard code by using equations.

A coded mass spectrometer incorporates a spatial or temporal code to reduce the resolution / sensitivity dichotomy inherent in mass spectrometry. The code is used to code one or more portions of a mass spectrometer. Coding patterns, such as Hadamard codes, Walsh codes, and perfect code sequences can be used. The coding can be spatial, for example, by using an aperture mask and / or temporal, for example, by coded injection of ions for analysis.

The correction of the light frequency of a light source may not be needed, a transmission belt is not increased, but a plurality codes are used. The light frequency width of the light source is set to be FSR and the code length of all codes are set to be FSR and is enabled to be provided with the orthogonality. Each light intensity frequency characteristic of an nth optical coded signal is set to be Cn(f)=[1+cos(2pion sf / FSR+r pion / 2) / 2(s is an integer of 1-the maximum code / 2, r=0or1)], the orthogonality is given between the optical encoding signal, or continuous light frequency code chips are distributed to the arrangement of code chips which form the optical encoding signal in turn, the light frequency of each code chip '1'is output, and codes such as a Hadamard code word (0101) and (0011) of a repeated second order and a filter with optical filter characteristics of a connecting code which connects the Hadamard code word are used to enable light source light to obtain the optical optical encoding signal. A coding light frequency region (31) and a decoding light frequency region (32) are covered on a drifting region of light source frequency. Delta F1and Delta F2 in the graph 13 are drifts of the light source frequency.

The device can be used for generating, in the framework of a CDMA communications terminal, both Walsh-Hadamard channeling codes and OVSF channeling codes. The device comprises a code generator preferably configured for generating Walsh-Hadamard codes. When the device is used for generating Walsh-Hadamard codes, the corresponding index values, applied to an input of the device, are sent to the input of the code generator. Generation of OVSF codes envisages, instead, that the corresponding indices, sent to an input of the device, undergo mapping, which enables generation, starting from the OVSF code, of the corresponding index identifying a string of symbols that is identical within the Walsh-Hadamard code. In this way each string of OVSF code symbols is generated, so producing, by means of the code generator, the generation of the identical string of symbols included in the Walsh-Hadamard code.

The invention discloses a threshold value processing method of Hadamard code modulation correlation imaging. The segmentation threshold is determined according to the gray histogram characteristics ofthe reconstructed image obtained by Hadamard matrix modulation correlation imaging, then, the target image is segmented by using the determined segmentation threshold, and the image after the threshold segmentation is subjected to morphological filtering. The morphological filtering comprises the following steps: firstly, the image after the threshold segmentation is subjected to etching operation to eliminate the point noise in the image, and then the binary target image contour is obtained by dilation operation; at last, the outline of the target image is used to enhance the image after thethreshold segmentation, and the point noise around the target image is removed to obtain a clear image. The threshold value processing method of the invention has high feasibility, obtains nearly 8dBoptical image enhancement, has good effect on binary images and gray images, and effectively promotes the practicality of the correlation imaging technology.

The invention discloses a carrier synchronization method based on coding and pilot frequency joint assistance. The method comprises the steps that: first, an LDPC-Hadamard code with a short code length and low code rate is designed, an optimal pilot frequency structure is designed based on a valuation theory, a carried rough synchronization method is designed based on correlation functions and ideas, and the valuation precision can reach a Cramer-Rao bound (CRB); and then soft demodulation and decoding operation are carried out on a roughly synchronized signal, soft modulation is carried out on soft information which is output after decoding, and the fine synchronization of carrier is carried out with the soft modulation signal based on expectation maximum algorithm. Simulation shows that the high-order QAM carrier synchronization method based on coding and pilot frequency joint assistance can greatly improve the carrier synchronization accuracy and scope, reduce the decoding times of a decoder, and work in deep space, a satellite and other communication systems with low signal-to-noise ratio.

The invention provides a cascading Hadamard code-aided iterative carrier synchronization scheme under an environment with an extremely low signal to noise ratio (SNR). By using the scheme, even under the environment with an extremely low SNR, accurate synchronization and correct decoding can be realized, and more importantly, the synchronization range is enlarged. In the invention, a transmittingend and a receiving end are utilized. The transmitting end is used for coding low density parity check (LDPC)-Hadamard cascading codes and adding pilot frequency. At the receiving end, different fromthe conventional simple pilot frequency unicode-aided carrier method, the method provided by the invention comprises the following steps: firstly, carrying out Hadamard code related search by using the orthogonality of Hadamard codes to pre-estimate a wide range of frequency offset and compensate the frequency offset, thus the frequency offset is greatly compensated in the process; secondly, extracting the pilot frequency of the compensated information for coarsely synchronizing; carrying out fine synchronization by utilizing the ideas of decoding iteration and maximum likelihood; and finally, carrying out decoding judgment.

A memory circuit, such as an embedded DRAM array, stores information as groups of bits or data using information coding in storage and retrieval data, instead of each bit being stored separately. Write data words can be mapped to storage format words that are stored and defined by a Hadamard matrix. The storage format word is stored as charge levels in an addressable memory location. For retrieving stored data, charge levels are read from the storage cells and interpreted to a valid storage format word. Hadamard code maximal likelihood decoding can be used to derive a read data word corresponding to a previously written write data word. The write data word is then output as the result of a read of the selected addressable location, or a portion thereof. The mapping can be two or more Hadamard matrix mappings concatenated for each of a plurality of storage format words.

The invention is directed toward a variable spectral phase encoder. The variable spectral phase encoder includes a plurality of switches and at least one encoder. The encoder is coupled between a first switch and second switch among the plurality of switches. The first switch selectively routes an optical signal to some combination of fixed encoders such that their collective product applies one of the Hadamard sequences to the optical signal.

The invention discloses an electricity structure for improving the DMD Hadamard transformation spectrograph coding efficiency, and belongs to the technical field of photoelectric instrument manufacturing. In order to solve the problem that in the prior art, a Hadamard transformation spectrograph is quite long in encoding and collecting time and controls an FPGA to prestore Hadamard coding stripe data in a FLASH, the electricity structure is provided. A Cortex-M3 sends a coding beginning instruction to the FPGA through an RS-232, after the FPGA receives the instruction, 255-frame coding stripe data in the FLASH are read in a DDR2 internal storage, a DAD drives a DMD to play coding stripes for coding of spectra, when the DMD is stabilized, the FPGA sends a synchronizing signal to trigger the Cortex-M3 to collect spectrum signals, signals collected by a detector are amplified by a direct-current amplifying circuit and converted through an ADC to obtain digital signals, finally, the measured signals are stored in the Cortex-M3, and decoding is performed after coding is completed.

A computer-implemented method of processing a query vector and a data vector), comprising: generating a set of masks and a first set of multiple signatures and a second set of multiple signatures by applying the set of masks to the query vector and the data vector, respectively, and generating candidate pairs, of a first signature and a second signature, by identifying matches of a first signature and a second signature. The set of masks comprises a configuration of the elements that is a Hadamard code; a permutation of a Hadamard code; or a code that deviates from a Hadamard code or a permutation of a Hadamard code in less than 40% of its elements.

The invention relates to a super low bit rate code auxiliary carrier wave synchronization method for deep space communication. According to the method, combination design for a pilot frequency and a super low bit rate code parameter can be carried out at a sending end, coarse synchronization is carried out at a reception end by employing the pilot frequency, the super low bit rate code is further combined to facilitate carrier waves to realize precise synchronization, and thereby large-scale carrier wave synchronization under the super low signal-to-noise ratio is realized. The method is advantaged in that the method works under the super low signal-to-noise ratio, and the carrier wave synchronization scope is large. According to the method, construction of a system, a low bit rate and a short code length LDPC-Hadamard code is mainly illustrated on the basis of the pilot frequency and coding combined auxiliary synchronization algorithm, combination and synchronization of the pilot frequency, the low bit rate and the short code length LDPC-Hadamard code are mainly analyzed, the detailed flow chart is provided, moreover, performance of the method is analyzed.

A method for generating and transmitting a cell ID code for cell recognition is disclosed. The first 16-bit cell ID codes for 2-bit FBI field are generated from 16-bit Hadamard codes, and the first and ninth bits of the Hadamard codes are punctured, to thereby generate the second 14-bit cell ID code for the 2-bit FBI field. The puncturing is performed by a network or a terminal.

A method and apparatus for generating a code in an asynchronous code division multiple access mobile communication system is provided. Specifically, the method and apparatus are for use in a transmitter in a mobile communication system which has multiple code groups having inherent code indices in response to each of slots, which selects one code group from among the multiple code groups, and which generates a second synchronization code corresponding to any one slot from among multiple slots, which are included in the selected code group. The method and apparatus determine position information designating a Hadamard code necessary for generating the second synchronization code by performing the steps of (1) in response to any one slot, outputting a value, which is obtained by subtracting 1 from a code index included in the selected code group, as a binary bit row; and (2) selecting one bit row, which employs the binary bit row as an upper bit and employs a binary code “0000” as a lower bit, as position information which designates the Hadamard code.

The invention discloses a kidney segmentation method in a CT image based on deep learning. The method comprises the following steps: inputting a CT image group; carrying out normalization processing on each image in the image group; generating a position coding graph of the kidney, and superposing the position coding graph with each image; carrying out convolution on all the images, determining aninterested position area, carrying out pixel Hadamard code product on all the processed images, and obtaining segmented images; binarizing the image at the output end; and carrying out Hadamard codeproduct on the obtained image and each image after normalization processing, and determining and outputting the image of which the kidney part is segmented. According to the method, the position codesare added when the neural network is used for training the images, so that the problem that the spleen and the kidney are difficult to distinguish can be well distinguished and solved; besides, an attention mechanism is used, so that the network fitting convergence speed is higher, the network can pay attention to the kidney position area, and therefore, spleen interference is eliminated.

A method and apparatus are disclosed for modulating a communication signal in a code division multiple access (CDMA) environment using orthogonal N by N Hadamard spread spectrum codes Orthogonal spreading codes are used that have lengths that are not a power-of 2 to provide additional channel variability for various multimedia applications and increase the flexibility of the number of channels / bandwidth relationship. The Hadamard codes are multiples of 4 (4n) and demonstrate a good cross-correlation property, making them very useful in the flexible design of code division multiple access (CDMA) systems. A transmitter encodes each of to N data streams (N not being a power of 2), to be transmitted using a 4n codeword, Ni. The received signal is passed through a filter matched to the characteristics of the appropriate codeword, Ni, and PN spreading sequence.