125 results about "Linear code" patented technology

A method and apparatus whereby a fingerprint verifier has a mechanism to slide a prism over an imaged area of a camera. The position of the prism being determined by a binary absolute linear code on a sliding mechanism imaged by the same camera at the side of the fingerprint wherein the images are knitted together to simulate a large CCD.

An M code envelope detector receives an incoming binary offset carrier (BOC) signal, such as the M code signal, and generates inphase BOC and quadraphase BOC signals, separated by an offset, that have respective ambiguous correlation envelopes, that when combined, provide a near unimodal correlation function with respect to code phase error of the BOC signal having an inherent multimodal autocorrelation function, with the near unimodal correlation envelope being tracked by early and late code replicas at broad one chip phases for providing unambiguous but nonlinear code phase error tracking, which detector is then further improved with the use of code replicas having narrow partial chip phases, such as ⅛ chip phases, for providing near linear code phase error tracking for unambiguous and accurate code tracking of the BOC signal.

Improved method of encoding and repairing data for reliable storage and transmission using erasure codes, which is efficient enough for implementation in software as well as hardware. A systematic linear coding matrix over GF(2^q) is used which combines parity for fast correction of single erasures with the capability of correcting k erasures. Finite field operations involving the coding and repair matrices are redefined to consist of bitwise XOR operations on words of arbitrary length. The elements of the matrix are selected to reduce the number of XOR operations needed and buffers are aligned for optimal processor cache efficiency. Decode latency is reduced by pre-calculating repair matrices, storing them in a hashed table and looking them up using a bit mask identifying the erasures to be repaired.

The present invention relates to a decoding method and a decoder, a program, a recording-and-reproducing apparatus and a method, and a reproducing apparatus and a method that are suitable for decoding encoded data encoded by using a linear code on ring R. A low-density processing unit performs parity-check-matrix low-density processing, performs linear combination for rows of a parity check matrix included in an obtained reception word, and generates a parity check matrix according to the linear-combination result, thereby reducing the density of the parity check matrix used for decoding, at step S21. Then, at step S22, an LDPC decoding unit performs decoding by using a sum product algorithm (SPA) by using the parity check matrix whose density is reduced through the processing performed at step S21. Where the processing at step S22 is finished, the LDPC decoding unit finishes decoding for the reception word. The present invention can be used for an error-correction system.

A method of decoding soft input information related to a transmitted word of a linear block code (n, k) and providing hard or soft output information is disclosed. The method comprises the steps of forming a reliability vector from the input information, identifying (n−k) linearly independent least reliable symbols and k most reliable symbols, converting a parity check matrix of the linear block code to a pseudo-systematic form with respect to the least reliable symbols, calculating extrinsic information and composite information for the most reliable symbols using the soft input information and the pseudo-systematic parity check matrix, and calculating extrinsic information for the least reliable systems using composite information for the most reliable symbols.

An encoder uses output symbol subsymbols to effect or control a tradeoff of computational effort and overhead efficiency to, for example, greatly reduce computational effort for the cost of a small amount of overhead efficiency. An encoder reads an ordered plurality of input symbols, comprising an input file or input stream, and produces output subsymbol. The ordered plurality of input symbols are each selected from an input alphabet, and the generated output subsymbols comprise selections among an output subsymbol alphabet. An output subsymbol is generated using a function evaluator applied to subsymbols of the input symbols. The encoder may be called one or more times, each time producing an output subsymbol. Output subsymbols can then be assembled into output symbols and transmitted to their destination. The functions used to generate the output subsymbols from the input subsymbols can be XOR's of some of the input subsymbols and these functions are obtained from a linear code defined over an extension field of GF(2) by transforming each entry in a generator or parity-check matrix of this code into an appropriate binary matrix using a regular representation of the extension field over GF(2). In a decoder, output subsymbols received by the recipient are obtained from output symbols transmitted from one sender that generated those output symbols based on an encoding of an input sequence (file, stream, etc.).

An electroluminescent (EL) panel with 2T1C subpixels is compensated for initial nonuniformity (“mura”). The current of each subpixel is measured at a selected time to provide a status signal representing the characteristics of the subpixel. A compensator receives a linear code value and changes it according to the status signals. A linear source driver drives the panel with the changed code values.

The invention provides methods and apparatus for transmitting and receiving a source data block in a wireless communication system using hybrid automatic retransmission request protocol. According to the scheme provided by the invention, at transmitting side, the source data block or part of source data block that is not decoded correctly at receiving side is divided into a plurality of data segments, each the plurality of data segments may be paded with known data to expand the data segments to be a predetermined lengthen, the data segment is encoded with linear code to be a data packet including the data segment and a redundancy information segment or including only redundancy information, and after that the encoded data packets are transmitted. At the receiving side, when each of the received data packets includes a data segment and a redundancy information segment, decoding is performed directly based on the received data packet, decoding is performed based on the received redundancy information segment and an data segment and redundancy information segment extracted from buffered data packets with a first and second chance to restore the data segment that is not decoded correctly in previous decoding processing. With the additional decoding chance, the scheme provided by the invention can improve decoding probability and thus the transmission efficiency of the system.

The present invention provides a decoding apparatus for carrying out a decoding process on a ring-R linear code. The decoding apparatus includes coded-word holding means for acquiring a coded word with a code length reduced by omission of some symbols from the coded word and for holding the coded word; known-information addition means for attaching a reliability level of each of the symbols omitted from the coded word to reduce its code length as known symbols each having a known value to the coded word held by the coded-word holding means as known information; and repetitive decoding means for repeatedly carrying out a decoding process using belief propagation on the coded word including the known information attached to the coded word by the known-information addition means.

This invention discloses a method and system for generating a private key and a corresponding public key. These keys can be used for encrypting a message into a cipher-text for transmission through an insecure communication channel, and for decrypting said ciphertext into a clear plaintext. The goal of the present invention is to provide encryption and decryption methods of the McEliece type which are capable of improving the security level of a post-quantum cryptosystem. In one embodiment, this object is achieved by three methods: a method for creating a public key from a private linear code generator matrix, a method for encrypting a message into a ciphertext and a method for decrypting the cipher-text into a plaintext. The key generation and encryption methods of the present invention comprises the following steps:

• • selecting an [n, k] linear code generator matrix G_s=[g₀ , . . . , g_n] over GF(q) as the private key, where k, w, n and q are positive integers and where g₀ , . . . , g_n−1 are length k column vectors; selecting k×1 random matrices C₀ , . . . , C _w−1; selecting a k×k non-singular matrix S; selecting an (n+w)×(n+w) matrix A; selecting an (n+w)×(n+w) permutation matrix P; and setting the public key as G=S[g₀ , . . . , g_n−w, C₀ , . . . , g_n−1, C_n−1]AP.
  • receiving the public key G, which is a k×(n+w) matrix over a finite field GF(q); generating an error vector e having elements in GF(q) and having a predetermined weight t; and encrypting a message vector m, to a ciphertext vector y=mG+e.

The main difference between the proposed cryptosystem and known variants of the McEliece cryptosystem consists in the way the private generator matrix is disguised into the public one by inserting and mixing random columns within the private generator matrix.

The invention relates to a quasi-cyclic low-density parity-check (QC-LDPC) code and a correcting and linear coding method thereof. The variable nodes of the LDPC code, the dimensionality of which is greater than 2, are informational nodes; and the variable nodes the dimensionality of which is 2 form a big end-to-end ring on a bipartite graph. The correcting method comprises the following implementation steps: randomly selecting one edge on the big ring the dimensionality of which is 2, cutting off the edge, and filling 0 in the corresponding position of a low-density check matrix, thereby acquiring a corrected structure of the code. The linear coding method of the corrected code comprises the following implementation steps: firstly, multiplying an input information vector s and a part of the check matrix the load of which is greater than 2 as a vector by a matrix to acquire an intermediate vector u; directly intercepting the corresponding position of the intermediate vector u to acquire a coding vector the variable node dimensionality of which is 1; computing bit by bit from a start bit according to the characteristics of the big ring on the bipartite graph to acquire a coding vector the variable node dimensionality of which is 2; and combining the two coding vectors to finally form a coding vector.

A communication method using random linear coding is disclosed. The communication method using a random linear code comprises receiving first code blocks randomly linear-coded from a transmitter; demodulating the first code blocks using a decision distance determined in accordance with a channel status; determining whether an error has occurred in the first code blocks, using the decision distance, and transmitting a NACK signal to the transmitter, the NACK signal including information of the number of the code blocks where an error has occurred. Since a block error rate can be controlled in accordance with channel status, throughput can be improved.

The invention relates to a high-resolution remote sensing image airplane detecting method based on high-level feature extraction of a depth boltzmann machine. The method comprises the steps that at first, a picture is divided into a plurality of segments, then scale-invariant feature transformation (SIFT) is utilized for extracting key points in the segments, the key points serve as low-level features of the segments, then a local restriction linear coding algorithm is utilized for coding the low-level features to obtain medium-level features, then the three-layer depth boltzmann machine is utilized for obtaining high-level features of the segments from the medium-level features, then the high-level features are utilized for training a support vector machine classifier, finally the classifier is used for detecting an airplane of the detected picture, and the airplane detection result high in accuracy and robustness can be obtained.

A decoding device for a linear code on a ring R, the decoding device including: a plurality of storage media; and a processing section; wherein the processing section uses a part of reliability of all symbols at a previous time to update reliability of each symbol in a process of iterative decoding for increasing the reliability of each symbol, and further retains a part used to update retained reliability information and a part unused to update the retained reliability information on two separate storage media.

A class of n×l nonlinear block codes, termed Go-CDMA codes are constructed using column-reduced and row-reduced Hadamard orthogonal matrices, termed Go-CDMA matrices. Here n,l are positive integers: n chips of user data are transmitted in frames of size l≦αn, where α is the frame expansion factor. The codes map n-vectors containing binary message data to binary or multi-level l-vectors for transmission, where l≧n. The codes are invertible maps for the binary message data, and when there is no message data in some input vector elements, and noise added between the coding and decoding, there is some error correction. The coding uses integer arithmetic and integer quantization operations, preferably certain sign operations. Go-CDMA codes may be implemented in CDMA communication systems to improve performance on many measures over conventional CDMA and TDMA systems. The coding and decoding may include scrambling and descrambling the Go-CDMA coded signal based on random codes.

The invention provides a system LT code compiling method based on the superposition degree. The method comprises the following compiling steps: conducting initialization, defining input nodes S, middle nodes I and redundancy check nodes R, constructing a BP translatability matrix in advance, and utilizing S=I G<ENC> to generate the I; generating the R by the I in a distribution mode through the superposition degree; using the S and the R as output nodes to be sequentially sent out. SPDD degree distribution is designed and optimized for the middle nodes of system coding, a DD doping level component is arranged in a superposition mode on the basis of WRSD degree distribution, the full coverage probability on information nodes is effectively ensured, and meanwhile the method has the advantages of ensuring linear code compiling complexity and partial recovery of the middle nodes and theoretically proving the asymptotic performance of the SPDD.

Disclosed is an apparatus for encoding data into linear codes on a ring R, including: as many shift registers as the length of information input thereto, the shift registers having a plurality of memory elements; a shift adding unit for adding values which are cyclically input depending on a check matrix for the linear codes, from the shift registers; a storage unit for storing parity values of the linear codes; and an accumulative adding unit for adding a sum from the shift adding unit and the parity values of the linear codes stored in the storage unit to each other to determine new parity values of the linear codes, and supplying the new parity values to the storage unit.

The invention discloses an image classification method based on an RGB-D fusion feature and sparse coding. The method comprises following steps of (1) extracting dense SIFT features and PHOG features of a color image and a depth image; (2) carrying out feature fusion on the extracted features of the images by use of a linear serial connection form so as to obtain four kinds of different fusion features finally; (3) using the K-means++ clustering method to carry out clustering processing on the different fusion features so as to obtain four kinds of different vision dictionaries; (4) carrying out local restriction linear coding on each vision dictionary to obtain different image expressing sets; and (5) using the linear SVM to classify the different image expressing sets and using a vote decision method to decide final classification conditions of the obtained classification results. According to the invention, the method is high in classification precision.

The invention relates to a video coding code rate control method based on a Rho domain, which pertains to the technical field of multimedia communication; the invention comprises the steps as follows: the bit rate of a group of pictures (GOP) is confirmed according to a given target code rate, and the bit rate distribution of frame-level is further respectively confirmed according to three frames which are an I-frame (Intra-frame frame), a P-frame (unidirectional predictive frame) and a B-frame (bidirectional predictive frame); the characteristic parameters of the previous frames of the same type are checked to predict the slope parameter Theta of a linear code rate model, model interception difference Delta c, the ratio s of motion vector code rate and entropy coding code rate that is quantified by residual coefficient, and zero coefficient proportion Rho that meets the code rate limit is calculated; a Rho-QP mapping table is referred to obtain a quantization parameter (QP) which is used for coding the current video frame. The code rate control method of the invention is simple and practical, and has excellent performance and the original video coding standards.