Abstract: A recording and reproducing apparatus includes a reproduction signal detection unit reproducing a two-dimensional pattern previously recorded on a holographic recording medium or user data recorded on the holographic recording medium, a reference pattern storage unit previously storing a reference pattern to be provided when the two-dimensional pattern is reproduced, a correction information generation unit comparing a reproduction reference pattern signal corresponding to the reproduced two-dimensional pattern with the stored reference pattern and removing fixed distortion contained in the reproduction reference pattern signal to generate correction information used for reproducing the reference pattern from the reproduction reference pattern signal, a correction information storage unit storing the correction information, and a distortion correction unit performing a correction calculation for a reproduction data signal using the correction information to generate corrected reproduction data from which the

Abstract: A hologram recorder/player includes recording beam modulation controller which causes a spatial light modulator to modulate the recording beam in such a way that a hologram is recorded in a plurality of blocks in a unit recording region and that each of the blocks includes recording information (DATA) and error correction code, at a time of recording. The hologram recorder/player includes incident angle variable controller which varies a reference beam incident angle to a plurality of predetermined angles with respect to the unit recording region. The recording beam modulation controller causes the modulation of the recording beam in such a way that a different hologram is generated for a page each time the reference beam incident angle is varied and that the hologram in each page is recorded in a plurality of the blocks.

Abstract: A data storage medium includes a data area used for storing data, an address area used for identifying the data area, a first mark that is formed in the address area and represents a bit string corresponding to an address, and a second mark that is formed in a vicinity of the address area and indicates a position where each of all bits in the bit string corresponding to the address is arranged.

Abstract: A recording and reproducing apparatus has a recording control section for multiplex-recording data in one of recording unit regions of a holographic recording medium; a reproducing control section for selectively reproducing the data multiplex-recorded in the recording unit region; a measuring section for causing specific data to be recorded in a recording unit region A to measure a maximum multiplex-recordable number N of the region A; a multiplicity setting section for setting (i) a multiplex-recording number M (M<N) of data to be recorded in the region A and (ii) a multiplex-recording number (N?M) of a buffer region of the region A, by using the maximum multiplex-recordable number N; and a storage section for storing the number N and the number M. When data B is to be recorded in the region A beyond multiplex-recording number M, the recording control section multiplex-records page data B in the buffer region of the region A within the range of the maximum multiplex-recordable number N.

Abstract: A recording and reproducing apparatus includes a light source to emit a laser beam, an information light beam irradiation unit to irradiate a medium with an information light beam, a reference light beam irradiation unit to irradiate the medium with a reference light beam so as to form a specific speckle pattern on the medium. The reference light beam irradiation unit comprises a diffusion board provided in the way of a light path through which the laser beam is passed and generating the reference light beam, a rotation controller to rotate the diffusion board, and an identification information detector to detect identification information previously formed on a surface of the diffusion board. The diffusion board comprises a plurality of encode storage regions in which different identification information is formed and a plurality of diffusion pattern generation regions specified by the identification information.

Abstract: In an apparatus for recording and regenerating data, a pass metric is calculated based on a likelihood converted from a previous calculation result iteratively until all pass metrics of the same data recorded many times on a recording medium are calculated, and then data recorded on the recording medium is decoded.

Abstract: This invention is a holographic recording medium including a track in which position information to specify a recording position and a reproducing position of page data is formed. The position information of the track is formed of position detection patterns. The position detection patterns each including a first detection mark row including center pits arranged at predetermined intervals; and a second detection mark row including side marks arranged at the same intervals as the intervals of the center pits, the side marks having lengths substantially corresponding to integral multiples of the intervals of the center pits. The second detection mark row is arranged adjacent to the first detection mark row such that both ends of the side marks are arranged so as to correspond to the center pits in a track width direction, and page data is recorded and reproduced on the basis of positions of the center pits or positions of the ends of the side marks.

Abstract: A recording and reproducing apparatus includes a reproduction signal detection unit reproducing a two-dimensional pattern previously recorded on a holographic recording medium or user data recorded on the holographic recording medium, a reference pattern storage unit previously storing a reference pattern to be provided when the two-dimensional pattern is reproduced, a correction information generation unit comparing a reproduction reference pattern signal corresponding to the reproduced two-dimensional pattern with the stored reference pattern and removing fixed distortion contained in the reproduction reference pattern signal to generate correction information used for reproducing the reference pattern from the reproduction reference pattern signal, a correction information storage unit storing the correction information, and a distortion correction unit performing a correction calculation for a reproduction data signal using the correction information to generate corrected reproduction data from which the

Abstract: A holographic recording medium according to the present invention includes a holographic material layer in which information is to be recorded by irradiating the same region with information light corresponding to the information to be recorded and reference light to read the recorded information. The holographic material layer is divided into a plurality of recording zones by a plurality of light shielding walls. The light shielding wall is formed of a material which does not transmit bleaching light to be applied to the recording zone in which a recording process has been performed and the recorded information is to be fixed.

Abstract: In a data recording apparatus, values of parity bits to be additionally provided every one predetermined length block in data obtained by demodulating the original data are determined so as to satisfy a part of or an entire the predetermined run length limitation rule in ranges of a current predetermined length block, the plurality of parity bits, and a next predetermined length block that is positioned next to the current block. The parity bits having the values are additionally provided to the current block.

Abstract: A holographic recording medium according to the present invention includes a holographic material layer in which information is to be recorded by irradiating the same region with information light corresponding to the information to be recorded and reference light to read the recorded information. The holographic material layer is divided into a plurality of recording zones by a plurality of light shielding walls. The light shielding wall is formed of a material which does not transmit bleaching light to be applied to the recording zone in which a recording process has been performed and the recorded information is to be fixed.

Abstract: In an apparatus for recording and regenerating data, a pass metric is calculated based on a likelihood converted from a previous calculation result iteratively until all pass metrics of the same data recorded many times on a recording medium are calculated, and then data recorded on the recording medium is decoded.

Abstract: The present invention provides a data recording device that can restrain the low-pass component in data to be written onto a recording medium without causing a problem in decoding the data using likelihood information. This data recording device includes: a data bit string combining unit that combines, by predetermined combining rules, a plurality of predetermined parity bit strings one by one with a data bit string obtained prior to a change to the bit order in a bit order rearranging procedure, thereby generating a plurality of composite data bit strings; and a data bit string selecting unit that selects one encoded data bit string from a plurality of encoded data bit strings generated through encoding procedures including the bit order rearranging procedure carried out for each of the plurality of composite data bit strings. Based on the selected encoded data bit string, the data recording device performs a data write operation onto the recording medium.

Abstract: The invention is a recording and reproducing apparatus for recording data on a recording medium having a holographic recording area and a buffer recording area. The recording and reproducing apparatus has a holographic recording controller which multiplexedly records user data as page data in a holographic form on the holographic recording area, a buffer recording controller which records user data on the buffer recording area, and a recording controller, upon receiving a user data write request, which controls recording of user data in the write request on which one of the holographic recording area and the buffer recording area.

Abstract: A holographic recording medium is a medium which records and reproduces data by irradiation with an information beam and a reference beam. This medium includes a user region for recording user data; and a calibration region for storing calibration data for calibrating an element which determines a recording and reproducing characteristic of a recording and reproducing apparatus for recording and reproducing data on/from the recording medium. The calibration data stored in the calibration region includes pattern information for measuring the element determining the recording and reproducing characteristic of the recording and reproducing apparatus.

Abstract: A recording and reproducing apparatus according to the present invention includes a light source for emitting a light beam, a spatial modulating part for modulating the light beam to create information light, using spatial information associated with page data A to be recorded on a holographic recording medium, an optical-path changing part for changing an optical path of the information light created by the spatial modulating part, a light detecting part for receiving the information light having the optical path changed by the optical-path changing part, and a diagnosis part for inspecting operations of recording and reproducing components including the spatial modulating part and the light detecting part, using the page data A and page data B obtained from the information light received by the light detecting part.

Abstract: A reproducing apparatus for an optical recording medium, comprising: a reference beam irradiator for irradiating an optical recording medium on which information is recorded by holography with a reference beam to generate a reproduction beam; a two-dimensional image pickup device capable of being partially read, which receives the reproduction beam; a partial reading controller for controlling partial reading of information on the two-dimensional image pickup device; and an information processor for performing a predetermined process by using the information to be partially read.

Abstract: The invention provides a data recording device comprising: an interval counter; an ? counter; and a segment counter, wherein the interval counter and the ? counter operate with a clock having a constant frequency which is independent of clock information, the interval counter is reset when division information is detected and, also, is reset and activates the ? counter when it reaches a count value corresponding to a segment length, the ? counter is reset when the division information is detected and, also, is reset and increments the count value of the segment counter when it reaches a count value corresponding to a predetermined length smaller than the segment length, and the segment counter increments its count value when the division information is detected and outputs a writing inhibition signal when it reaches a count value corresponding to the frame length.

Abstract: The present invention provides a data recording device that can restrain the low-pass component in data to be written onto a recording medium without causing a problem in decoding the data using likelihood information. This data recording device includes: a data bit string combining unit that combines, by predetermined combining rules, a plurality of predetermined parity bit strings one by one with a data bit string obtained prior to a change to the bit order in a bit order rearranging procedure, thereby generating a plurality of composite data bit strings; and a data bit string selecting unit that selects one encoded data bit string from a plurality of encoded data bit strings generated through encoding procedures including the bit order rearranging procedure carried out for each of the plurality of composite data bit strings. Based on the selected encoded data bit string, the data recording device performs a data write operation onto the recording medium.

Abstract: A data reproduction device in conformity to Viterbi decoding includes an inverted-selected path generation part for receiving a selected path and an inverted candidate, selecting and modifying the selected path corresponding to the inverted candidate so as to produce a inverted-selected path that is an inverted version of the selected path, and outputting a number of the inverted-selected paths in parallel, the number corresponding to a number of the inverted candidates selected for the selected path of a predetermined data length and a second candidate data generation part for generating second candidate data from the inverted candidate. The device further includes a data selection part for selecting between the first and the second candidate data based on error detecting results.