Fujitsu Corporation

Toshihiko Morita

Toshio Ito

Takao Sugawara

Masaru Sawada

Tsugito Maruyama

Shinji Kanda

Susumu Kawakami

Jun Wakitani

Yuichi Sato

Toshikazu Kanaoka

Hiroaki Okamoto

Yusuke Yasukawa

Yasushi Inamoto

Fumi Hasegawa

Motomu Takatsu

Mitsuhiko Ohta

Naoyuki Sawasaki

Kazuhito Ichihara

One set of syndromes is calculated from a first data string from among a plurality thereof including at least 2t+1 pieces of symbols as a parity string, and coefficients of an error locator polynomial from the one set of the syndromes. Whether or not a correction is successful is judged by using the coefficients of the error locator polynomial and the same calculation is performed for a second data string if a correction failure is judged. Contrarily, if a correction success is judged, an error of the first data string is corrected by using the aforementioned set of the syndromes and the coefficients of the error locator polynomial.

Error correction apparatus

An encoder divides the data in which sector data is adjacently connected to a first RS parity generated in Reed Solomon encoding into blocks to and subjects each of the blocks to cyclic Hamming encoding so as to generate Hamming parities. Subsequently, the data in which the Hamming parities are aligned in a row is subjected to Reed Solomon encoding so as to generate a second RS parity, and encoded data in which the first RS parity and the second RS parity are adjacently connected to the sector data is output. A decoder s divides the sector data and the first RS parity into n blockes and cyclic Hamming encoding, aligns the parities thereof, corrects errors in the parities by Reed Solomon decoding by the second RS parity, then corrects 1-bit errors in blockes by cyclic Hamming decoding, and further corrects errors of 2 or more bits by Reed Solomon decoding by the first RS parity.

Error correction device, encoder, decoder, method, and information storage device

A decoder decodes a code by selecting, based on a predetermined condition, a path out of paths representing a transition of each of states in a trellis diagram. A storing unit stores, when a path at time k is selected, information on a selection history of a path selected at time prior to time (k&#x2212;(a constraint length of a code)+1). A path detecting unit detects a path to be excluded from a path selection candidate, based on the information stored in the storing unit and information on a state of a transition source when a state transition occurs from time k&#x2212;1 to time k.

Decoder and decoding method for decoding a code by selecting a path out of paths in a trellis diagram

An information sequence having a code length of N (N=K+M), where K is information length and M is parity length, is encoded into a code sequence by using an LDPC code. The LDPC code is generated based on a matrix H, with M rows and N columns. The matrix H includes a check matrix Hand a check matrix H. The check matrix Hhas M rows and M columns, it is a cyclic permutation matrix, and an inverse matrix exists for the check matrix H, and its column weight is 3. The check matrix Hhas M rows and K columns.

Encoder, decoder, methods of encoding and decoding

A record reproduction apparatus includes an encoding unit that encodes sector data to be written into a recording medium, by dividing the data into a predetermined number of blocks, and an iterative decoding unit that iteratively decodes the sector data read from the recording medium, by dividing the sector data into the predetermined number of blocks.

Record reproduction method, apparatus, and circuit for using error correcting code

When a zero run, which violating G constraint of a run-length-limited (RLL) code, is detected from the data stored in a first input registerand a second input register, bits before and after the zero run is transferred to a temporary registervia a bus for zero run removalto be combined to each other. Thus, by effectively using the mechanism of bus transfer, a circuit can be simplified, thereby realizing a small circuit.

Encoder and decoder using run-length-limited code

An encoded-bit-string generating unit generates a bit string encoded by scrambling an input bit string. A direct-current-component evaluating unit selects a bit string having a predetermined width in the bit string generated by the encoded-bit-string generating unit, while shifting bits one by one, and evaluates the direct-current component in the selected bit string. A bit-string extracting unit extracts a bit string with suppressed direct-current component, based on a result of an evaluation by the direct-current-component evaluating unit.

Encoder and decoder

A recording and reproducing apparatus having an ECC-less error correction function, includes an erasure detector generating an erasure flag indicating erasure of a read signal; and an iterative decoder having two soft-in/soft-out (SISO) decoders, i.e., an inner decoder and an outer decoder, and correcting the erasure by inputting the erasure flag einto the inner decoder and performing erasure compensation in the inner decoder. As the erasure compensation in the inner decoder, channel information is masked while the erasure flag is on. The erasure of data due to a media defect is detected inside the iterative decoder, and the second erasure flag is inputted into the inner decoder to perform erasure compensation in the inner decoder.

Recording and reproducing apparatus, signal decoding circuit, error correction method and iterative decoder

A recording and reproducing apparatus includes an RLL encoder that encodes an information bit string to a code bit string and a RLL decoder that decodes the code bit string to the information bit string. The RLL encoder encodes the information bit string to the code bit string of a run-length-limited code at a high encoding rate satisfying a plurality of conditions of constraint regarding a string of successive zeros. The RLL decoder decodes the code bit string encoded by the RLL encoder to the information bit string.

Recording and reproducing apparatus

An information recording/reading apparatus employs a preamble to reproduce a clock used when recording information in a recording medium and reads the information out of the recording medium at a timing synchronized with a read signal. The preamble is split and recorded by replacing a middle portion of the preamble with data and a sync byte. While a first buffer is employed to delay signal data read out of the recording medium, a frequency offset detector detects a frequency offset using the split preamble.

Method of and apparatus for recording/reading information, circuit for recording/reading signal

In a Maximum A posteriori Probability decoding (MAP decoding), a correlation and a deviation of noises for past and future states which depend on input signal patterns in past N bits and future Q bits are calculated by training by a noise correlation arithmetic operating unitand they are stored. Upon reproduction, in a white noise arithmetic operating unit, white noise values for the past and future states in which colored noises are converted into white noises are obtained by using the stored correlation and deviation of the noises. In an input signal arithmetic operating unit, an input signal (channel information) &#x39b;c(y|S) of the MAP decoding is calculated from the white noise values and the deviation for the past and future states. A likelihood in the MAP decoding is obtained from the input signal.

Information recording and reproducing apparatus and method and signal decoding circuit having improved noise processing characteristics

A local region image tracking apparatus continuously tracks an arbitrary local region within a search image which is described by search image data by comparing the search image data and reference image data related to the arbitrary local region having a size of am pixels by bn pixels with respect to input image data, where the search image has a size larger than am pixels by bn pixels, and,, b, m and n are natural numbers. The local region image tracking apparatus includes correlation computing circuit for computing a correlation between reference image data related to a reference image having a size of m pixels by n pixels and the search image data a plurality of times while moving a position of the reference image with respect to the search image, and for outputting correlation values respectively indicating a computed correlation, and a correlation value accumulating circuit for accumulating the correlation values output from the correlation computing circuit, and for outputting a correlation value indicative of a correlation between the search image data and reference image data related to an equivalent of a reference image having a size of am pixels by bn pixels.

Image tracking apparatus for tracking an image within a local region to continuously track a moving object

An image processing process wherein an image is divided into small areas, a polar transformation is applied to the image in each of the small areas, and image processing is performed based on the result of the polar transformation. Further, each of a plurality of images is divided into small areas, a polar transformation is applied to the image in each of the small areas for each of the plurality of images, and correlation is obtained between the results of the polar transformation for the plurality of images. One-dimensional filter processing is applied to the polar-transformed output.

Process and apparatus for extracting and recognizing figure elements

An image-feature tracking apparatus for tracking an object includes a feature deriving part for deriving at least one feature in an image of the object, and a matching operation part for matching two frames of the image defined at different times in the image of the object and producing an approximate motion vector of the feature. The apparatus further includes a motion-vector correcting part for correcting the approximate motion vector provided in the matching operation part based on a position of the feature derived in the feature deriving part. In the image-feature tracking apparatus, from a corrected motion vector provided in the motion-vector correcting part, a position of the object is detected.

Growing community of inventors

Kawasaki, Japan

Toshihiko Morita