JP2007066376A - Hologram recorder and hologram recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a two-dimensional modulation system suitable for recording information to a hologram recording medium. <P>SOLUTION: The information to be recorded is converted to a two-dimensional code symbol for each prescribed unit, for each byte, for instance. Then, a rotation group, a group sub sync and a group main sync are generated in the order from the two-dimensional code symbol, the group main syncs are arrayed and a physical page is generated. Then, the physical page is made with an element hologram and recorded on a hologram material. The group sub syncs are vertically and horizontally arrayed for the group main sync constituting the physical group, and a page retrieval symbol having a main synchronization symbol is arranged at the center. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention two-dimensionally modulates sound information such as sound / music, image information such as a still image / moving image, or text file, and then records the information as an element hologram on a hologram recording medium such as a sheet type. The present invention relates to a hologram recording apparatus and a hologram recording method, and more particularly to a two-dimensional modulation method of the information.

Japanese Patent No. 2833975

  As an example of recording information on a sheet-like recording medium, a one-dimensional code or a two-dimensional code represented by a bar code, a QR code, a dot code, and the like can be given. However, in these information recording media, the amount of information that can be recorded per unit area is extremely low, about several tens to several kilobytes. This is because there is a physical limit to the recording resolution of simple image density printing.

  Similarly, as a sheet-like recording medium, a hologram recording medium that records various data by interference fringes of object light and reference light is also known. It is also known that the hologram recording medium can dramatically increase the recording density and can be significantly increased in capacity, for example, for computer data, AV (Audio-Visual) content data such as audio and video, etc. It is considered useful as a large-capacity storage medium.

  When data is recorded on the hologram recording medium, the data is imaged as two-dimensional page data. Then, the imaged data is displayed on a liquid crystal panel or the like, and the light transmitted through the liquid crystal panel is irradiated with object light, that is, object light that becomes an image of two-dimensional page data, on the hologram recording medium. In addition, the hologram recording medium is irradiated with reference light from a predetermined angle. At this time, the interference fringes generated by the object light and the reference light are recorded as one element hologram such as a dot shape or a strip shape. That is, one element hologram is a record of one two-dimensional page data.

By the way, considering a hologram memory such as a sheet, for example, a system for recording computer data, AV content data, etc., and allowing a general user to acquire data recorded in the hologram memory using a reproducing device as a hologram reader think of.
The sheet-shaped hologram memory is a recording that records a large number of element holograms on a plane as a medium surface, and data recorded as each element hologram with the hologram reader facing the medium surface. Is to be read.

  When the hologram technique is used, the amount of information that can be recorded per unit area can be dramatically improved over normal printing. However, the conventional one-dimensional or two-dimensional pattern modulation method used for barcode and QR code methods is intended for information recording on ordinary two-dimensional printed matter, and its application to hologram recording itself is not possible. Not considered.

  Therefore, an object of the present invention is to provide a two-dimensional pattern modulation method suitable for recording information on a hologram recording medium. In particular, it is a two-dimensional modulation method suitable for recording a large amount of information on a so-called hologram-printed sheet-like medium.

  The hologram recording apparatus of the present invention is a hologram recording apparatus that converts recording information into a physical page as two-dimensional page data, and records the physical page as an element hologram. Then, two-dimensional modulation means for converting binary data for each predetermined unit as recording information into a two-dimensional code symbol, synthesizing the two-dimensional code symbol, and generating a group sub-sync including a sub-synchronization pattern, and the two-dimensional Physical page generation means for generating a group main sync using the group subsync generated by the modulation means and a main synchronization symbol, and generating the physical page by a plurality of the group main syncs; and the physical page as an element hologram In this way, element hologram arraying means for generating an element hologram array is provided.

The two-dimensional modulation means generates the two-dimensional code symbol by setting a pixel at a specific corner in the two-dimensional code symbol of N × N pixels as a sub-synchronization pixel. Then, by combining the four two-dimensional code symbols as a set and performing the necessary rotation processing for each of the four two-dimensional code symbols, each sub-synchronous pixel is positioned at the four corners. A rotated group of 2N × 2N pixels is generated. Further, the four rotation groups are combined in two horizontal groups and two vertical groups, and the four sub-sync pixels collected in the central 2 × 2 pixels after the combination are the sub-sync pattern. The group subsync is generated.
In this case, the necessary rotation processing performed by the two-dimensional modulation means for each of the four two-dimensional code symbols is that the first two-dimensional code symbol is not rotated and the second two-dimensional code symbol is rotated 90 ° to the right. The third two-dimensional code symbol is rotated by 180 °, and the fourth two-dimensional code symbol is rotated by 90 ° to the left.
In addition, two pixels adjacent to the sub-synchronization pixel having a specific corner in the two-dimensional code symbol of N × N pixels are set as sub-guard pixels that protect the sub-synchronization system.
Further, the physical page generation means arranges the group main sync by arranging a page search symbol having the main sync symbol and an integer multiple of the group sub sync in the group sub sync array. And a plurality of the group main sinks are two-dimensionally arranged to generate the physical page.
The two-dimensional modulation means generates the two-dimensional code symbol as a pattern in which a black level and a white level are assigned to each of N × N pixels, and a pattern in which the white level is continuous vertically, horizontally, or diagonally. A two-dimensional code symbol of a pattern selected in accordance with a value of binary data in a predetermined unit is generated from the patterns excluding.
The main synchronization symbol is composed of a white level pixel group having a size larger than the two-dimensional code symbol of the N × N pixels.

  The hologram recording method of the present invention is a two-dimensional modulation that converts binary data for each predetermined unit as recording information into a two-dimensional code symbol, synthesizes the two-dimensional code symbol, and generates a group subsync including a sub-sync pattern A physical page generation step of generating a group main sync using the group subsync generated in the two-dimensional modulation step, a main synchronization symbol, and generating a physical page with a plurality of the group main syncs; An element hologram arraying step for generating an element hologram array by converting a physical page into an element hologram is provided.

  That is, in the present invention, information to be recorded is converted into a two-dimensional code symbol for each predetermined unit (for example, every byte). Then, a rotation group, a group subsync, and a group main sync are generated in order from the two-dimensional code symbol, and a physical page is generated by arranging the group main sync. The physical page is converted into an element hologram and recorded on the hologram material.

According to the present invention, information to be recorded is converted into a two-dimensional code symbol for each predetermined unit (for example, every byte). Then, a rotation group, a group subsync, and a group main sync are generated in order from the two-dimensional code symbol, and a physical page is generated by arranging the group main sync. By converting the physical page into an element hologram, an appropriate two-dimensional pattern can be easily converted into an element hologram.
In particular, after performing the necessary rotation processing for each two-dimensional code symbol with a pixel at a specific corner in the two-dimensional code symbol of N × N pixels as a sub-synchronous pixel and a set of four two-dimensional code symbols. Combining to produce a 2N × 2N pixel rotation group with each sub-sync pixel located at the four corners. Further, the four rotation groups are combined in two horizontal groups and two vertical groups, and the four sub-sync pixels collected in the central 2 × 2 pixels after the combination are the sub-sync pattern. The group subsync is generated. In this way, a 2 × 2 pixel sub-synchronization pattern can be generated from a two-dimensional code symbol generated by one type of two-dimensional modulation table, and a group sub-sync can be generated without performing complicated processing. .
Further, the white level region as the sub-synchronization pattern is clarified by the sub-guard pixel.

In addition, a group subsync is formed from four rotation groups, the center of which is a subsynchronization pattern, and a page search symbol having, for example, a main synchronization symbol having a 4 × 4 symbol configuration is arranged. The synchronous center position seen in the above can be configured in a uniform state in the physical page.
In addition, by prohibiting conversion to a two-dimensional array that continues vertically / horizontally / diagonally as a two-dimensional code symbol, two-dimensional run length can be limited to 6 pixels or less, and distinction from the main synchronization symbol is clear. It becomes. In particular, when the main sync symbol is composed of a group of white level pixels having a size larger than an N × N pixel two-dimensional code symbol, for example, when a continuous pattern of 8 pixels is used in the main sync symbol, The main synchronization symbol can be easily identified. In other words, it is possible to prevent erroneous detection of the main synchronization symbol in the physical page.
In addition, by setting the page search symbol to a size that is an integral multiple of the group subsync, even if the page search symbol is placed at any symbol position on the group main sync, the center of gravity position of the main sync symbol and the sub sync pattern is vertical. Regularity can be maintained on both the axis and the horizontal axis.

Hereinafter, embodiments of the present invention will be described in the following order.
[1. Recording and playback of hologram memory]
[2. Overview of overall data encoding process]
[3. Data page generation process]
[4. In-page encoding process]
[5. Inter-page encoding process]
[6. Hologram array generation process]
[7. Effects of the embodiment]

[1. Recording and playback of hologram memory]

First, a basic recording / reproducing operation of the hologram memory 3 will be described with reference to FIG.
FIG. 1A shows a state of data recording on the hologram memory 3. For example, when data such as content data or a computer program is recorded in the hologram memory 3, the entire recording data is encoded into a large number of data for one page.
One piece of data DT as an encoded unit is converted into, for example, two-dimensional barcode image data as shown in the figure, and is displayed on the liquid crystal panel 1 as a two-dimensional page data image.
The laser light L1 output from a predetermined light source, for example, converted into parallel light, passes through the liquid crystal panel 1 on which the two-dimensional page data image is displayed, and thus the object light L2 as an image of the two-dimensional page data image and Become.
The object light L2 is collected by the condenser lens 2 and collected as a spot on the hologram memory 3.
At this time, the recording reference light L3 is irradiated to the hologram memory 3 at a predetermined angle. Thereby, the object light L2 and the reference light L3 interfere with each other, and a dot-shaped element hologram is recorded by the interference fringes.
When the condenser lens 2 is used in this way, the data recorded as the element hologram becomes a Fourier image of the recording data image by the Fourier transform action of the condenser lens 2.

In this way, one element hologram is recorded in the hologram memory 3, but the data DT of the encoding unit is sequentially converted into two-dimensional page data in the same manner, displayed on the liquid crystal panel 1, and recorded as an element hologram. Go.
When recording each element hologram, the position of the hologram memory 3 (hologram material) is transferred (or the recording optical system is transferred) by a transfer mechanism (not shown), and the recording position of the element hologram is set on the plane of the hologram memory 3. Then shift it slightly. Thereby, for example, recording is performed on the sheet-like hologram memory 3 so that a large number of element holograms are arranged in the plane direction. For example, in FIG. 45, one element hologram is represented by ●, and a number of element holograms are thus formed on a plane.

The hologram memory 3 in which element holograms are recorded in this way is reproduced as shown in FIG. The collimator lens 4 and the imager 5 shown in FIG. 1B are configured in a reproducing apparatus as a hologram reader.
The hologram memory 3 is irradiated with the reproduction reference light L4 at the same irradiation angle as that during recording. When the reproduction reference light L4 is irradiated, a reproduction image recorded as an element hologram is obtained. That is, an image of two-dimensional page data appears at a location conjugate with the liquid crystal panel 1 at the time of recording. This may be read by the imager 5.
That is, the reproduced image light L5 from the hologram memory 3 is collimated by the collimator lens 4 and enters the imager 5 formed by, for example, a CCD image sensor array or a CMOS image sensor array. Since the Fourier image on the hologram memory 3 is subjected to inverse Fourier transform by the collimator lens 4 and becomes an image of two-dimensional page data, the reproduced image as the two-dimensional page data image is read by the imager 5.
The imager 5 generates a reproduced image signal as an electric signal corresponding to the reproduced image. By decoding the reproduced image signal, original data, that is, data before being converted into two-dimensional page data for recording can be obtained.
By reading data similarly for a number of element holograms on the hologram memory 3, the original recorded content data and the like can be reproduced.

Note that angle multiplex recording is known as a recording method for such a hologram memory 3. Angle multiplexing is a method of multiplexing and recording element holograms at the same position on a plane by changing the angle of the recording reference light L3.
For example, if one element hologram is recorded as shown in FIG. 1A and then the irradiation angle of the recording reference light L3 is changed, another element hologram can be recorded at the same plane position on the hologram memory 3.
In other words, the plane of the hologram memory 3 can be used for multiple recording by changing the angle of the recording reference beam L3, thereby greatly increasing the recording capacity. For example, FIG. 45 shows an image in which a large number of element hologram arrangement surfaces are formed.
When reproducing the hologram memory 3 subjected to angle multiplexing recording, the reproduction reference light L4 may be irradiated at the same angle as each recording reference light angle at the time of recording. That is, the element hologram recorded by irradiating the recording reference light L3 having the first angle can be read by irradiating the reproduction reference light L4 having the same first angle, and the recording reference light L3 having the second angle. Can be read out by irradiating the reproduction reference light L4 having the same second angle.

Note that the hologram memory 3 in which data is recorded by element holograms as described above can easily be mass-replicated by close copy.
Therefore, the hologram memory 3 in which the element hologram is recorded on the hologram material as shown in FIG. 1A may be used as a hologram memory for providing it to general users as it is. It may be used to duplicate the hologram memory.
For example, computer data, AV content data, and the like are recorded on a hologram recording medium and distributed widely, so that a general user can acquire data recorded in the hologram memory 3 using a reproducing device (hologram reader 20). 1A, a hologram master medium is generated as shown in FIG. 1A, a hologram memory replicated from the master medium is distributed, and data is operated by the operation of FIG. 1B on the user side. Is preferably read out.

[2. Overview of overall data encoding process]

Hereinafter, data encoding processing for recording in the hologram memory 3 will be described. FIG. 2 shows the configuration of the recording system and the state of the encoding process in each part.
An input data stream (Input Data Stream) in FIG. 2 is stream data of original data (input data) recorded in the hologram memory 3.
As the input data, various data such as audio contents, video contents, computer programs, or computer data are assumed.

  The recording system 10 includes a scrambled data page generator (Scrambled Data Page Generator) 11 that performs data page generation processing on input data supplied as a recording target, and an inner page encoder (Inner Page Encoder) that performs intra-page encoding processing. 12, an outer page encoder (Outer Page Encoder) 13 that performs inter-page encoding processing, and a hologram unit matrix generation unit (Hologram Unit Matrix Generator) 14 that generates hologram memory 3 by performing hologram array generation processing Is done.

Input data, which is target data to be encoded, has a size of m × n bytes as one unit. Each input data in one unit of m × n bytes is indicated by D [0], D [1]... D [mn−1]. Here, m is the number of pages of data to be encoded, and n is the number of data per page.
This input data is input to the scrambled data page generator 11. The scrambled data page generator 11 scrambles the input data and generates m pages of data as scrambled data pages SDP0, SDP1,... SDPm-1. These are output as a scrambled data page stream (Scrambled Data Page Stream).

  The scrambled data pages SDP0, SDP1,... SDPm-1 are input to the inner page encoder 12. The inner page encoder 12 performs intra-page encoding processing on the input scrambled data page, and generates data for m pages as the internal encoded pages IEP0, IEP1,... IEPm-1. These are output as an inner encoded page stream.

  The stream data of the inner encoded pages IEP0, IEP1,... IEPm-1 is input to the outer page encoder 13. The outer page encoder 13 performs inter-page encoding processing on the input inner encoded page, and outputs x, y, z pages as outer encoded pages OEP0, OEP1,... OEPxyz-1. Generate data. These are output as an outer encoded page stream.

The stream data of the externally encoded pages OEP0, OEP1,... OEPxyz-1 is input to the hologram unit matrix generation unit 14. The hologram unit matrix generation unit 14 performs element hologram processing on the externally encoded page, and element holograms HU (0, 0)... HU (x-1, y-1) of xy units are recorded. A hologram unit matrix 20 is formed. This hologram unit matrix is obtained by recording element holograms on a hologram material by the operation of FIG. 1A, and may be the hologram memory 3 itself or a master medium for duplicating the hologram memory 3.
In this specification, the hologram unit matrix 20 is used as a general term indicating what is recorded so that a number of element holograms (= hologram units) are arranged on a hologram material.

FIG. 3 shows the process in each part.
FIG. 3A shows the processing of the scrambled data page generation unit 11. In the scrambled data page generation unit, a pre-process page generation process A1, a sector division process A2, an EDC addition process A3, a scramble process A4, and a page combination process A5 are sequentially performed, and a scrambled data page SDP stream (Scrambled Data Page Stream) is output.
FIG. 3B shows processing of the inner page encoder 12. In the inner page encoder 12, a data array conversion process B1, an intra-page encoding process B2, an intra-page interleaving process B3, and a data array inverse conversion process B4 are sequentially performed to generate an internal encoded page IEP stream (Inner Encoded Page Stream). Is output.
FIG. 3C shows processing of the outer page encoder 13. In the outer page encoder 13, a page arrangement conversion process C1, an inter-page encoding process C2, a page multiplexing process C3, an inter-page interleaving process C4, and a page arrangement re-conversion process C5 are sequentially performed to generate an externally encoded page OEP stream. (Outer Encoded Page Stream) is output.
FIG. 3D shows the processing of the hologram unit matrix generation unit 14. In the hologram unit matrix generation unit 14, a page ID generation process D1, a page ID encoding process D2, a synchronization signal generation process D3, a crosstalk detection symbol generation process D4, first and second two-dimensional modulation processes D5 and D6, a page A search symbol generation process D7, a physical page generation process D8, and an element hologram arrangement process D9 are performed, and recording as an element hologram as described with reference to FIG. 1 is performed, and a hologram unit matrix 20 is generated.

[3. Data page generation process]

Data page generation processing in the scrambled data page generation unit 11 will be described in detail.
FIG. 4 shows the processes A1 to A5 of the scrambled data page generator 11 shown in FIG.
A pre-processing page generation process A1 is performed on the input data to generate a pre-processing page (Row Pages).
In the sector division process A2, a pre-process sector (Raw Secors) is generated from a pre-process page (Raw Pages).
In the EDC addition processing A3, sectors with EDC (Sectors with EDC) are generated from sectors before processing (Raw Secors).
In the scramble process A4, scrambled data sectors (Scrambled Data Sectors) are generated from the sectors with EDC (Sectors with EDC).
In the page combination process A5, scrambled data pages are generated from scrambled data sectors (Scrambled Data Sectors).

Each process will be described sequentially.
First, pre-processing page generation processing A1 is performed on raw bytes as input data D [0], D [1]... D [mn-1]. Low byte means the data before processing.
The input data (low byte) is composed of m × n data groups as shown in FIG.
The pre-processing page generation process A1 sequentially divides the data group as raw bytes into n-byte data series to generate pre-processing pages (Raw Pages) shown in FIG. As shown in the drawing, m pages before processing Raw Page [0], Raw Page [1]... Raw Page [m-1] are generated. For example, the pre-process page Raw Page [0] is formed of n bytes of input data D [0]... D [n−1]. The other pre-processing pages are each n bytes.

Next, each pre-processing page Raw Page [0], Raw Page [1]... Raw Page [m-1] is divided into s pre-processing sectors by sector division processing A2. That is, as shown in FIG. 7, the pre-processing page Raw Page [0] includes the pre-processing sector Raw Secor [0] [0], Raw Secor [0] [1]... Raw Secor [0] [s-1 ] S sectors before processing. Similarly, the raw page Raw Page [1] includes s number of processes of the raw sector Raw Secor [1] [0], Raw Secor [1] [1] ... Raw Secor [1] [s-1]. Divided into previous sectors. The same applies to the raw page Raw Page [m-1].
All pre-processing pages are divided into s pre-processing sectors, so that m × s pre-processing sectors Raw Secor [0] [0]... Raw Secor [m-1] [s-1 ] Is formed as shown in FIG. In FIG. 8, the configuration of each pre-processing sector Raw Secor [0] [0]... Raw Secor [m-1] [s-1] is represented by input data.
This pre-processing sector is a processing unit of EDC (error detection code), which will be described later, and includes t bytes (t = n / s). For example, the pre-process page Raw Page [0] is formed of t bytes of input data D [0]... D [t−1].

Subsequently, in EDC addition processing A3, EDC (error detection code) is added to each pre-processing sector Raw Secor [0] [0]... Raw Secor [m−1] [s−1].
FIG. 9 shows a configuration when u-byte EDC (error detection code) is added to each sector before processing. For example, for the pre-process sector Raw Secor [0] [0], u-byte EDC parity E [0], E [1] with respect to t bytes of input data D [0]... D [t-1]. ... E [u-1] is added, and this is regarded as a sector with EDC (Sector with EDC [0] [0]). Similarly, EDC parity is added to other pre-processing sectors. As a result, m × s sectors with EDC Sector with EDC [0] [0], Sector with EDC [0] [1]... Sector with EDC [m-1] [s-1] are formed. .

Next, in the scramble processing A4, each sector with EDC Sector with EDC [0] [0], Sector with EDC [0] [1]... Sector with EDC [m-1] [s-1] is scrambled. Processing is performed, and scrambled data sectors (Scrambled Data Sectors) shown in FIG. 10 are generated.
As can be seen from FIGS. 9 and 10, the byte data of each sector with EDC is converted to byte data SD after scramble.
For example, input data D [0]... D [t-1] and EDC parities E [0], E [1]... E constituting the sectors with EDC [0] [0] in FIG. [u-1] is scrambled to form a scrambled data sector Scrambled Data Sectors [0] [0] consisting of byte data SD [0], SD [1]... SD [v-1] in FIG. Is done. Note that the v bytes forming the scrambled data sector is the number of bytes (t + u) bytes constituting the sector with EDC.
The other sectors with EDC are also scrambled. As a result, m × s scrambled data sectors Scrambled Data Sectors [0] [0], Scrambled Data Sectors [0] [1]... Scrambled Data Sectors [m-1] [s-1] are formed. The

Page combination processing A5 is performed on the scrambled data sector. In this case, as shown in FIG. 11, the s sector is combined with one page to generate a scrambled data page SDP (Scrambled Data Pages).
That is, the scrambled data sectors Scrambled Data Sectors [0] [0]... Scrambled Data Sectors [0] [s-1] are combined to form the scrambled data page SDP0. Similarly, the scrambled data sectors are combined to form a scrambled data page SDPm-1.
FIG. 12 shows the configuration of each scrambled data page SDP0, SDP1,... SDPm-1 of m pages.
Each scrambled data page consists of r bytes. r = n + u × s bytes.
2, the scrambled data pages SDP0, SDP1,... SDPm-1 are supplied from the scrambled data page generator 11 to the inner page encoder 12.

[4. In-page encoding process]

The scrambled data pages SDP0, SDP1,... SDPm-1 obtained by the above-described data page generation processing in the scrambled data page generation unit 11 are subjected to intra-page encoding processing by the inner page encoder 12.
FIG. 13 shows the processes B1 to B4 of the inner page encoder 12 shown in FIG.
In the data array conversion process B1, information data blocks (Info Data Blocks) are generated from the scrambled data page SDP.
In the intra-page encoding process B2, code data blocks (Code Data Blocks) are generated from the information data blocks (Info Data Blocks).
In inter-page interleaving processing B3, interleaved code data blocks (Interleaved Code Data Blocks) are generated from the code data blocks (Code Data Blocks).
In the data array inverse transformation process B4, an inner encoded page is generated from the interleaved code data block (Interleaved Code Data Blocks).

Each process will be described sequentially.
The scrambled data pages SDP0, SDP1,... SDPm-1 input to the inner page encoder 12 are array-converted for intra-page encoding in the data array conversion process B1, and an information data block (Info Data Generate Blocks).
FIG. 14 shows an example in which the constituent bytes of each scrambled data page are arranged in horizontal a byte × vertical b byte in order to perform a two-dimensional product code. Note that a × b = r. The r byte is the number of constituent bytes of one scrambled data page as shown in FIG.
For example, FIG. 14 shows data SD [0]... SD [r−1] constituting the scrambled data page (Scrambled Data Page [0] = SDP0) in FIG. Information data block (Info Data Block [0]), and the array-converted data is represented by I [0] [0] [0] ... I [a-1] [b-1] [0] Yes.
In this way, the scrambled data pages SDP0, SDP1,... SDPm-1 are rearranged, and information data blocks Info Data Block [0], Info Data Block [1]. It is formed.

In the notation of I [α] [β] [γ], α represents a column index (column number), β represents a row index (row number), and γ represents a page index (page number).
The correspondence between the data SD of the scrambled data page and the array-converted I [α] [β] [γ] is I [α] [β] [γ] = SD [a · b · γ + a · β + −α ].

Next, in intra-page encoding process B2, correction parity is added to the information data block (Info Data Blocks) to generate a code data block (Code Data Blocks). FIG. 15 shows an example in which c bytes of parity P are added in the horizontal direction and d bytes of parity P are added in the vertical direction.
For example, with respect to the information data block Info Data Block [0] in FIG. 14, a c-byte parity P [a] [0] [0]... In the horizontal direction and a d-byte parity P in the vertical direction as shown in FIG. [0] [b] [0]... Is added to generate an i × j byte code data block Code Data Block [0]. i = a + c, j = b + d.
Parity P is similarly added to other information data blocks. As a result, m code data blocks Code Data Block [0]... Code Data Block [m−1] are generated.

The generated code data block Code Data Block [0]... Code Data Block [m-1] is subjected to interleaving processing that is completed within the page in interpage interleaving processing B3.
FIG. 16 shows an interleaved code data block Interleaved Code Data Block [0] ... Interleaved Code Data Block [0] obtained by interleaving each of the code data blocks Code Data Block [0] ... Code Data Block [m-1] in the page. m-1].
For example, interleaved data I [0] [0] [0]... P [i-1] [j-1] [0] constituting the code data block Code Data Block [0] shown in FIG. Is the data ICD [0] [0] [0]... ICD [i-1] [j-1] [0] in FIG. 16, which is an interleaved code data block of i × j bytes. [0].

The m interleaved code data blocks (Interleaved Code Data Blocks) generated as shown in FIG. 16 are subjected to inverse conversion of the data array to the original page unit in the data array inverse conversion process B4, and the internal encoded page IEP (Inner Encoded Pages) is generated.
FIG. 17 shows the inner encoded pages IEP0... IEPm-1. This is an example in which there are m pages of k-byte (k = i × j) internally encoded pages.
For example, the interleaved code data block Interleaved Code Data Block [0] in FIG. 16 is subjected to array reverse conversion, and k-byte inner encoded page of the data iep [0]... Iep [k−1] in FIG. IEP0. Subsequent interleaved code data blocks are similarly subjected to array inverse conversion, and become k-byte internal encoded pages IEP1 to IEPm-1 shown in FIG.
As described in FIG. 2, the inner encoded pages IEP0, IEP1,... IEPm−1 are output from the inner page encoder 12 and supplied to the outer page encoder 13.

[5. Inter-page encoding process]

The inter-coded pages IEP0, IEP1,... IEPm-1 obtained by the above-described intra-page encoding process in the inner page encoder 12 are subjected to inter-page encoding processing in the outer page encoder 13.
FIG. 18 shows processes C1 to C5 of the outer page encoder 13 shown in FIG.
An information page block (Info Page Blocks) is generated from the internally encoded page IEP in the page array conversion process C1.
In the inter-page encoding process C2, code page blocks (Code Page Blocks) are generated from information page blocks (Info Page Blocks).
In the page multiplexing process C3, a page multiplexed block (Duplicated Page Block) is generated from the code page block (Code Page Blocks).
In the inter-page interleaving process C4, interleaved duplicated blocks are generated from the duplicated page block (Duplicated Page Block).
Outer encoded pages (Outer Encoded Pages) are generated from interleaved duplicated blocks (Interleaved Duplicated Blocks) in page array reconversion processing C5.

Each process will be described sequentially.
For the internal encoded pages IEP0, IEP1,... IEPm-1, which are input to the outer page encoder 13, array conversion is performed to perform inter-page encoding in the page array conversion processing C1, and an information page block (Info Page Block) is generated.
FIG. 19 shows an example of an information page block in which inner encoded pages IEP0, IEP1,... IEPm-1 are array-converted into horizontal f pages × vertical e pages. The inter-encoded pages that have undergone layout conversion are indicated by IEP [0], IEP [1]... IEP [ef-1].

  Next, in an interpage encoding process C2, a correction parity page between pages is added to the information page block (Info Page Block) to generate a code page block (Code Page Blocks). FIG. 20 shows an example of a code page block generated by adding g-page external parity pages OPP [0]... OPP [eg-1] in the horizontal direction.

For this code page block, a page multiplexing process C3 multiplexes each page into a plurality of pages to generate a page multiplexed block (Duplicated Page Block). FIG. 21 is an example of page-multiplexed blocks in which each code page in the code page block is multiplexed by q. The code pages here are the inner coded pages IEP [0], IEP [1]... IEP [ef-1], and the outer parity pages OPP [0]... OPP [eg-1]. That's it.
As the multiplexing, the code pages IEP [0], IEP [1]... IEP [f-1], OPP [0]... OPP [g in the first row of the vertical e pages in FIG. -1] are multiplexed so as to form q rows (vertical q pages) as shown in FIG.
Similarly, each code page IEP [f], IEP [f + 1]... IEP [f + (f-1)], OPP [g]... OPP in the second row of the vertical e pages in FIG. [g + (g-1)] is multiplexed so as to have q rows (vertical q pages) as shown in FIG.
In the same manner, multiplexing is performed to generate a page multiplexed block (Duplicated Page Block) of vertical e × q pages in FIG.

This page multiplexed block (Duplicated Page Block) is subjected to interleaving processing across pages in interpage interleaving processing C4, and the interleaved page multiplexed blocks (Interleaved Duplicated Blocks) shown in FIG. Is generated.
FIG. 22 is an example of an interleaved page multiplexed block in which interleaving and array conversion are executed in the horizontal direction x page × vertical direction y page × angle multiplexing direction z page.
In FIG. 22, each page block in the angle multiplexing direction is represented as a layer, and each layer of the z page is represented by Rayer [0]... Rayer [z-1].
In the page block of each layer, each interleaved page is represented by IDP [x] [y] [z]. For example, each page in the layer Rayer [0] is IDP [0] [0] [0]... IDP [x-1] [y-1] [z].

As described above, in the interleaved duplicated blocks (interleaved duplicated blocks), the page arrangement is converted again into page units in the page arrangement re-conversion process C5, and an outer encoded page OEP (Outer Encoded Pages) is generated. .
FIG. 23 shows outer encoded pages OEP0... OEPxyz-1. This is an example where there are x, y, and z pages of k-byte outer coded pages.
The interleaved duplicated blocks (Interleaved Duplicated Blocks) in FIG. 22 are re-transformed into the page arrangement, and as shown in FIG. 23, k-byte outer coding by iep [0]... Iep [k-1] K-byte externally encoded page OEP1,... And each externally encoded page by generated page OEP0, iep [k]... Iep [k + (k-1)] are generated.
The outer encoded pages OEP0... OEPxyz-1 are output from the outer page encoder 13 as described with reference to FIG.

[6. Hologram array generation process]

The externally encoded pages OEP0, OEP1,... OEPxyz-1 are supplied to the hologram unit matrix generation unit 14, and finally the hologram unit matrix 20 is formed on the hologram material forming the hologram memory or its master medium.
FIG. 24 shows the processing of the hologram unit matrix generation unit 14. This shows the process shown in FIG. 3D in more detail.

  As shown in FIG. 24, stream data (Outer Encoded Page Stream) of outer encoded pages OEP0, OEP1,... OEPxyz-1 from the outer page encoder 13 is converted into a two-dimensional code by the first two-dimensional modulation process D6. Converted to symbols (2D Code Symbols).

The hologram unit matrix generation unit 14 generates a physical page ID (Logical Page ID) and a logical page ID (Logical Page ID) in the page ID generation process D1. The physical page ID and logical page ID are encoded by the page ID encoding process D2, and are used as a physical page ID code (Physical Page ID Code) and a logical page ID code (Logical Page ID Code).
Further, the physical page ID code and the logical page ID code are subjected to the second two-dimensional modulation processing D5, and a physical page ID code symbol (Physical Page ID Code Symbols) and a logical page ID code symbol (Logical Page) as a two-dimensional pattern. ID Code Symbols).

Further, the hologram unit matrix generation unit 14 generates main sync symbols for detecting the cut-out position of the two-dimensional symbol by the synchronization signal generation process D3.
In the hologram unit matrix generation unit 14, crosstalk detection symbols (Crosstalk Detect Symbols) are generated by the crosstalk detection symbol generation processing D4.

Physical page ID code symbols (Physical Page ID Code Symbols), logical page ID code symbols (Logical Page ID Code Symbols), main synchronization symbols (Main Sync Symbols), crosstalk detection symbols (Crosstalk Detect Symbols) are page search symbols. In combination with the generation process D7, page search symbols (Page Search Symbols) as a two-dimensional pattern are generated.
The page search symbols (Page Search Symbols) and the above-described two-dimensional code symbols (2D Code Symbols) are combined in the physical page generation process D8 to generate a physical page (Physical Pages). Each physical page is recorded in the hologram material as an element hologram in the element hologram array processing D9, and element holograms HU (0,0)... HU (x-1, y-1) as shown in FIG. A recorded hologram unit matrix 20 is formed. That is, as described with reference to FIG. 1A, while each physical page is sequentially displayed on the liquid crystal panel 1, element holograms are recorded on the hologram material by the interference fringes of the object light L2 and the recording reference light L3. At this time, by recording each physical page while changing the irradiation angle of the recording reference light L3, element holograms are formed by the angle multiplexing method.

Each process in the hologram unit matrix generation unit 14 will be described.
As the two-dimensional modulation processing D6, the externally encoded pages OEP0, OEP1,... OEPxyz-1 from the outer page encoder 13 are converted into two-dimensional code symbols (2D Code Symbols).
FIG. 25 shows two-dimensional modulation processing.
Byte data as an 8-bit binary code of D0 to D7 shown in FIG. 25A is converted into a two-dimensional code symbol as a two-dimensional pattern of 4 × 4 pixels (pixels) in FIG. For each pixel P0, P1,... Pf of this two-dimensional pattern, either the white level or the black level is selected according to the value of byte data, that is, the 8-bit value of D0 to D7.
As an example, FIG. 25C shows byte data of the value “01011010”, that is, “5Ah” (h represents hexadecimal notation), which is converted into the two-dimensional code symbol of FIG. 25D. Is done. In this example, three pixels P1, P7, and P9 are set to the white level, and the other 13 pixels are set to the black level.

Here, in order to express 8-bit byte data,
2 ⁸ = 256 [symbol]
2D code symbols are required. Here, “C” represents a combination, and the number of types of three combinations out of 13 is obtained.
13C3 = 286 [symbol]
Therefore, if the number of pixels of the two-dimensional code symbol is 13 pixels or more, the 256 combinations can be expressed.
Then, 3 pixels as 4 × 4−13 = 3 may be allocated for uses other than the representation of byte data.

Therefore, as shown in FIG. 26, among the 4 × 4 pixels, the pixel Pf is assigned as a sub-sync pixel to the auxiliary sync pattern pixel. Either a white level or a black level is assigned to the pixel Pf when a group subsync (Group-SS) described later is generated.
The pixels Pb and Pe are sub-sync guard pixels (SS-Guard Pixels) that guard the sub-sync pixels. The pixels Pb and Pe are always at the black level.
Then, as the remaining 13 pixels, pixels P0... Pa, Pc, and Pd are code pixels, and according to the byte data to be modulated, 3 of these 13 pixels are set to the white level, and 10 pixels are set to the black level. .

Here, since 13C3−2 ⁸ = 286−256 = 30 [symbol], 30 non-code symbols can be defined.
FIG. 27 is an example of 30 excluded two-dimensional symbols for the purpose of run length limitation.
The two-dimensional patterns other than 30 to be excluded are assigned to byte data values “00h” to “FFh”.
FIG. 28, FIG. 29, FIG. 30, FIG. 31, FIG. 32, FIG. 33, and FIG. 34 show two-dimensional patterns representing each of the byte data values "00h" to "FFh". That is, a modulation table from byte data to two-dimensional code symbols. In these drawings, the pixel value “0” indicates the black level, and “1” indicates the white level.
For example, as shown in FIG. 30, the byte data value “5Ah” is a two-dimensional code symbol shown in FIG. 25D because P1, P7, and P9 are assigned white level patterns.

  That is, as shown in FIG. 27, 30 patterns that are patterns in which white levels are continuous vertically, horizontally, or diagonally are excluded. Of the remaining 256 patterns, a two-dimensional code symbol is generated as a pattern selected in the modulation table of FIGS. 28 to 34 according to the value of 1-byte binary data.

As described above, 1-byte data is converted into a 4 × 4 pixel two-dimensional code symbol. From four bytes, that is, four 4 × 4 pixel two-dimensional code symbols, a group R (Group-R: Group Rotated ...) is generated.
FIG. 35 shows group R generation processing.
FIGS. 35 (a), (b), (c), and (d) show 4 bytes as byte data A, byte data B, byte data C, and byte data D, respectively.
Each byte data is converted into a 4 × 4 pixel two-dimensional pattern in accordance with the modulation table described above. The two-dimensional patterns generated according to the values of byte data A, B, C, and D are shown in FIGS. 35 (e), (f), (g), and (h).
The four two-dimensional patterns are rotated as follows.
Two-dimensional pattern of byte data A: no rotation → FIG. 35 (i).
Two-dimensional pattern of byte data B: right 90 ° rotation → FIG. 35 (j).
Two-dimensional pattern of byte data C: 180 ° rotation → FIG. 35 (k).
Two-dimensional pattern of byte data D: Left 90 ° rotation → FIG. 35 (l).
Then, the four symbols of FIGS. 35 (i), (j), (k), and (l) are combined to generate an 8 × 8 pixel group R shown in FIG. 35 (m).

From the 4-byte data, the group R is formed as described above. Four patterns of the group R are combined to generate a group sub-sync (Group-SS: Group Sub-Sync).
FIG. 36 shows a group subsync generation method.
36 (a), (b), (c), and (d), four groups R are shown. 36A shows a group R generated from byte data A, B, C, and D, FIG. 36B shows a group R generated from byte data E, F, G, and H, and FIG. Is a group R generated from byte data I, J, K, and L. FIG. 36D is a group R generated from byte data M, N, O, and P.
The four groups R are combined to generate a 16 × 16 pixel group subsync as shown in FIG. At this time, the white level is assigned to the pixel Pf in the two-dimensional pattern of 4 × 4 pixels for the byte data C, H, I, and N, so that 2 × gathered at the center of the group subsync as shown in the figure. Four pixels Pf of two pixels form a white area for four pixels. This is the subsync pattern.
Further, by assigning a black level to the pixels Pf of other byte data A, B, D, E, F, G, J, K, L, M, O, P, white pixels on the group subsync Suppress the frequency of

The above group subsyncs are formed by the two-dimensional modulation process D6, and provided to the physical page generation process D8 in FIG.
That is, in the two-dimensional modulation processing D6, the two-dimensional code symbol is generated by setting the pixel Pf at a specific corner in the 4 × 4 pixel two-dimensional code symbol as a sub-synchronization pixel.
Next, by combining the four two-dimensional code symbols as a set and performing the necessary rotation processing for each of the four two-dimensional code symbols, each sub-synchronized pixel Pf is placed at the four corners. An 8 × 8 pixel rotation group (group R) is generated.
Further, four rotation groups (group R) are combined in two horizontal groups and two vertical groups, and are combined into 2 × 2 pixels in the center after the combination, and four white synchronized sub-sync pixels Pf. However, the group subsync is generated so that the subsync pattern is obtained.

On the other hand, a page search symbol is generated by the page search symbol generation processing D7 in FIG. 24. The page search symbol is a physical page ID code symbol, a logical page ID code symbol, as shown in FIG. (Logical Page ID Code Symbols), main synchronization symbols (Main Sync Symbols), and crosstalk detection symbols (Crosstalk Detect Symbols). This page search symbol is formed of 32 × 32 pixels, that is, the number of pixels corresponding to four group subsyncs.
Each symbol in the page search symbol will be described later. In the physical page generation process D8, the page search symbol and the group subsync are combined to form a group main sync (Group Main-Sync). Further, a set of the group main sync is set as a physical page.

FIG. 38A shows the group main sync. The group main sync is formed by arranging eight group subsyncs in the horizontal direction and eight in the vertical direction.
However, in this case, 64 group subsyncs can be arranged, but 2 × 2 group subsyncs (32 × 32 pixels) at an arbitrary position are left blank and page search symbols are inserted. FIG. 38 shows an example in which page search symbols as shown in FIG. 37 are arranged in pixels (32 × 32 pixels) for four central group subsyncs.
That is, a page search symbol having a main synchronization symbol is arranged in the array of group subsyncs. The page search symbol is composed of an integer multiple of 16 × 16 pixel group subsyncs.
The group main sync configured as described above is formed of 128 × 128 pixels, and the breakdown includes 60 group subsyncs and one page search symbol.
As described above, one group sub-sync has 16 × 16 pixels and includes 16 bytes of 1-byte data expressed by 16 pixels. Therefore, the group main sync has 16 × 60 = 960 bytes (960 bytes) as data. Symbol).
In the group main sync, the positions of the center of gravity of the main sync symbol and the sub sync pattern (= four pixels of white level at the center of the group sub sync) are regular in both the vertical and horizontal directions.

Such a group main sync further arranged in a two-dimensional plane is a physical page. FIG. 39 shows a configuration example of a physical page.
Here, the group main sinks Group-MS [0] [0]... Group-MS [p-1] [q-1] are arranged so that there are p groups in the horizontal direction and q groups in the vertical direction. An example in which pages (Physical Pages) are formed is shown.
In the physical page generation process D8 of FIG. 24, such a physical page is formed, and this is provided to the element hologram arrangement process D9. That is, the physical page is displayed on the liquid crystal panel 1 as the two-dimensional page data of FIG.

In the physical page of FIG. 39, even-numbered group main syncs and odd-numbered group main syncs are shown as “EVEN” and “ODD” in each group main sync. Then, odd-numbered group main syncs / even-numbered group main syncs are alternately arranged in both the vertical and horizontal directions.
The even-numbered group main sync and the odd-numbered group main sync have different main synchronization symbols in the page search symbol. For example, since the page search symbol of FIG. 37 is inserted into the even-numbered group main sync, the result is as shown in FIG. On the other hand, a page search symbol as shown in FIG. 38B is inserted into the odd-numbered group main sync. As can be seen by comparing FIGS. 38A and 38B, the patterns of the main synchronization symbols are different.

Examples of physical pages are shown in FIGS. 40, 41, 42, 43, and 44. FIG. In this example, p = 4 and q = 3, and a physical page in which group main syncs of 4 groups in the horizontal direction and 3 groups in the vertical direction are arranged is illustrated. Since one group main sync is 128 × 128 pixels, this physical page is composed of 512 × 384 pixels.
FIG. 40 is an example of a preamble page.
FIG. 41 shows an example of increment data modulation.
FIG. 42 shows an example of random data modulation.
FIG. 43 shows an example of 00h fixed data modulation.
FIG. 44 shows an example of FFh fixed data modulation.

  Such physical pages are sequentially displayed on the liquid crystal panel 1 as described with reference to FIG. 1A, and the object light L2 and the recording reference light L3 that form an image of the physical page interfere with each other, and the interference fringes are one element. Recorded as a hologram. As each physical page is sequentially recorded as an element hologram, an element hologram is formed on the plane of the hologram material as indicated by ● in FIG. In this way, a hologram unit matrix in which element holograms are two-dimensionally arranged is formed.

Next, the main synchronization symbol formed in the synchronization signal generation process D3 in FIG. 24 will be described. As described above, the main synchronization symbol included in the page search symbol has its two-dimensional pattern properly used for the odd-numbered group main sync and the even-numbered group main sync.
FIG. 46A shows the main synchronization symbol added to the even-numbered group main sync, and FIG. 46B shows the main synchronization symbol added to the odd-numbered group main sync.
The main synchronization symbol of the even-numbered group main sync in FIG. 46 (a) is a 16 × 16 pixel two-dimensional pattern in which the center 8 × 8 pixels are at the white level and all the surrounding pixels are at the black level. It is a pattern.
In the main synchronization symbol of the odd-numbered group main sync in FIG. 46B, a white level pixel is assigned so as to have a ◇ shape (diamond) at the center in a 16 × 16 pixel two-dimensional pattern.
As described above, the main synchronization symbol is composed of a white level pixel group having a size larger than the 4 × 4 pixel two-dimensional code symbol.

FIG. 47 shows reproduction waveforms for even-numbered and odd-numbered main synchronization symbols. In FIG. 47, the trajectories irradiated with the reproduction reference light L4 during reproduction are shown as the scan trajectories S1, S2, and S3, respectively, and the reproduction waveforms obtained corresponding to the scan trajectories S1, S2, and S3, respectively. (Monochrome pattern detection waveform) is shown as reproduction waveforms P1, P2, and P3. As a reproduction waveform, an H level signal is obtained for a white level pixel.
As can be seen from this figure, depending on the pattern of even-numbered and odd-numbered main synchronization symbols, different reproduction waveforms are obtained depending on the scan position. That is, by determining the H level width as the reproduction waveform for each main synchronization symbol, the reproduction position (scan position) with respect to the recording pattern can be easily detected.

Although the two types of examples of the main synchronization symbol are shown in FIGS. 46A and 46B, three or more types of main synchronization symbols may be set and assigned to each group main sync. Further, the two-dimensional pattern as the main synchronization symbol is not limited to the patterns shown in FIGS. As described above, the pattern type of each main synchronization symbol may be set as a two-dimensional pattern in which different reproduction waveforms can be obtained according to the scan trajectory.

Next, the physical page ID code symbol and the logical page ID code symbol generated by the page ID generation process D1, the page ID encoding process D2, and the two-dimensional modulation process D5 of FIG. 24 will be described.
FIG. 48 shows the processing of the logical page ID. The logical page ID is an internal encoded page IEP (IEP [0], IEP [1],..., Which constitutes the code page block shown in FIG. 20 before the page multiplexing process C3 in the outer page encoder 13 is performed. An identification number uniquely assigned to IEP [ef-1]) and the external parity page OPP (OPP [0]... OPP [eg-1]).

FIG. 48A shows an example of a logical page ID, and in this example, an example in which a unique address of 8 bytes is added is shown. LID [0]... LID [7] indicates each 1-byte value constituting the logical page ID. As the page ID generation process D1, an 8-byte address value is generated by the LID [0]... LID [7].
Parity is added to the 8-byte address value in the page ID encoding process D2. FIG. 48B shows an example in which parity (LIDP [0]... LIDP [3]) for 4-byte error detection and correction is added to an 8-byte logical page ID.

The logical page ID code to which the parity is added is converted into a logical page ID code symbol by two-dimensional modulation processing D5. FIG. 48C shows a logical page ID code symbol.
The value of each byte LID [0]... LID [7] and LIDP [0]... LIDP [3] is converted into a two-dimensional pattern corresponding to the value in 16 pixels of 4 × 4, respectively. They are arranged in a logical page ID part as an area of pixels and vertical 16 pixels. Further, as shown in the figure, the four-pixel area and the 16-pixel area for the four symbols at the right end are all black guard portions that are black level pixels. This black guard portion is an area for securing a symbol interval with adjacent crosstalk detection symbols as shown in FIG.

FIG. 49 shows the processing of the physical page ID. The physical page ID is an internal encoded page IEP (IEP [0]) that forms the page multiplexed page block (Duplicated Page Block) of FIG. 21 after the page multiplexing process C3 in the outer page encoder 13 is performed. , IEP [1]... IEP [ef-1]) and an external parity page OPP (OPP [0]... OPP [eg-1]).
That is, even if the pages are logically identical, independent physical page IDs are added to the pages copied by the page multiplexing process C3.

FIG. 49A shows an example of a physical page ID. In this example, an example in which a unique address of 8 bytes is added is shown. PID [0]... PID [7] indicates each 1-byte value constituting the physical page ID. As the page ID generation process D1, an 8-byte address value is generated by PID [0]... PID [7].
Parity is added to the 8-byte address value in the page ID encoding process D2. FIG. 49B shows an example in which 4-byte error detection and correction parity (PIDP [0]... PIDP [3]) is added to the 8-byte physical page ID.

The physical page ID code to which the parity is added is converted into a physical page ID code symbol by two-dimensional modulation processing D5. FIG. 49 (c) shows a physical page ID code symbol.
The value of each byte PID [0]... PID [7] and PIDP [0]... PIDP [3] is converted into a two-dimensional pattern according to the value in 16 pixels of 4 × 4, respectively. It is arranged in a physical page ID part as an area for pixels and 12 pixels vertically. Further, as shown in the drawing, the area of 16 pixels in the horizontal direction and 4 pixels in the vertical direction corresponding to the four symbols at the lower end is a black guard portion in which all pixels are black level. This black guard portion is an area for securing a symbol interval with adjacent crosstalk detection symbols as shown in FIG.

Next, the crosstalk detection symbol generated by the crosstalk detection symbol generation processing D4 in FIG. 24 will be described.
FIG. 50 shows a rule for embedding a crosstalk detection symbol number in each element hologram arranged as a hologram unit matrix. In FIG. 50, one element hologram is indicated by a circle, and the number in the element hologram indicates a crosstalk detection symbol number. The crosstalk detection symbol number indicates the pattern type of the crosstalk detection symbol.

First, two types of element hologram arrangement methods are conceivable: a square lattice in FIG. 50A and a staggered lattice in FIG. 50B. As shown in FIGS. 50A and 50B, nine types of crosstalk detection symbol numbers “0” to “8” are assigned to these two-dimensional arrays.
FIG. 51 shows a crosstalk detection symbol. The crosstalk detection symbol is configured as 18 horizontal pixels × 18 vertical pixels.
As can be seen from FIG. 37, the horizontal 16 × vertical 2 pixels and the leftmost horizontal 2 × vertical 16 pixels of the top two rows of the crosstalk detection symbol are a logical page ID code symbol and a physical page ID code symbol. Thus, the page search symbol becomes a 32 × 32 pixel pattern.

The above horizontal 18 pixels × vertical 18 pixels have a total of 9 areas of 3 vertical areas × 3 horizontal areas with 6 pixels × 6 pixels as one area.
The crosstalk detection symbol in FIG. 51 indicates the crosstalk detection symbol number with four central pixels in nine 6 × 6 pixel regions within 18 horizontal pixels × 18 vertical pixels as white levels.
As shown in FIG. 50, a crosstalk detection symbol number is assigned to one element hologram. Each crosstalk detection symbol has four pixels in a region corresponding to the crosstalk detection symbol number in the pattern of FIG. Only the white level is set and all others are set to the black level.
FIG. 52 shows nine types of crosstalk detection symbols with crosstalk detection symbol numbers “0” to “8”.
For example, in the crosstalk detection symbol (Symbol [0]) of the crosstalk detection symbol number “0”, only four pixels indicated by “0” in FIG. 51 are white level, and the others are all horizontal 18 pixels. × It becomes a pattern of 18 vertical pixels.
Further, the crosstalk detection symbol (Symbol [1]) of the crosstalk detection symbol number “1” has 18 pixels horizontally, in which only 4 pixels indicated by “1” in FIG. 51 are white level and all others are black level. × It becomes a pattern of 18 vertical pixels.

  FIG. 52 also shows a crosstalk detection symbol to be added to a special page such as a preamble. In the crosstalk detection symbol added to the preamble or the like, all pixels have a black level pattern.

As described above, the crosstalk detection symbol is generated as a two-dimensional pattern of 9 regions (1 region = 6 × 6 pixels) in total by 3 regions × 3 regions by the crosstalk detection symbol generation process D4. In particular, a two-dimensional pattern in which one of the nine regions is a region including white level pixels and the other regions are all black level pixels.
Then, nine types of crosstalk detection symbols with crosstalk detection symbol numbers “0” to “8” are set by setting the region including the white level pixels in the nine regions.

Depending on the crosstalk detection symbol generation process D4, a plurality of types of crosstalk detection symbols (crosstalk detection symbol number “0”) are arranged in each element hologram arranged in the element hologram arrangement process D7 according to the position of each element hologram. ”To“ 8 ”), the crosstalk detection symbols of the respective numbers are output in a predetermined order so that the crosstalk detection symbols of the assigned numbers are included.
Further, adjacent element holograms output crosstalk detection symbols of respective numbers in a predetermined order so that different types of crosstalk detection symbols are given.

An example of how to use the crosstalk detection symbol will be described.
FIG. 53 shows an example of a crosstalk detection symbol reproduction image when the element holograms are arranged in a square lattice as shown in FIG. As shown in FIG. 53 (j), a circle indicates an element hologram, and a number in the circle indicates a crosstalk detection symbol number assigned to the element hologram. In addition, the dashed circles A to I indicate the tracking position during reproduction, that is, the center of the spot of the reproduction reference light L4.
This is a tracking example centering on the element hologram of the crosstalk detection symbol number 4.

When the reproduction is performed at the tracking position A in FIG. 53 (j), the intermediate position of the four element holograms to which the crosstalk detection symbol numbers 0, 1, 3, and 4 are assigned is reproduced. As shown in FIG. 53 (a), the reconstructed image is a reconstructed image obtained by combining the crosstalk detection symbols of the crosstalk detection symbol numbers 0, 1, 3, and 4, and the crosstalk detection symbol numbers 0, 1, 3, and 4 are combined. The white level portion corresponding to 4 is detected with a brightness of 25%.
When reproduced at the tracking position B in FIG. 53 (j), the intermediate position of the two element holograms of the crosstalk detection symbol numbers 1 and 4 is reproduced, so that the reproduced image of the crosstalk detection symbol is shown in FIG. As shown in b), a reproduction image is obtained by combining the crosstalk detection symbols of the crosstalk detection symbol numbers 0 and 4, and the white level portions corresponding to the crosstalk detection symbol numbers 0 and 4 have a brightness of 50%, respectively. Is detected.
When the reproduction is performed at the tracking position C in FIG. 53 (j), the intermediate position of the four element holograms of the crosstalk detection symbol numbers 1, 2, 4, and 5 is reproduced. As shown in FIG. 53C, the white level portions corresponding to the crosstalk detection symbol numbers 1, 2, 4, and 5 are detected with a brightness of 25%.
When reproduced at the tracking position D in FIG. 53 (j), the intermediate position between the two element holograms of the crosstalk detection symbol numbers 3 and 4 is reproduced, so that the reproduced image of the crosstalk detection symbol is shown in FIG. As shown in d), the white level portions corresponding to the crosstalk detection symbol numbers 3 and 4 are detected with a brightness of 50%, respectively.
When reproduced at the tracking position E in FIG. 53 (j), the position directly above the element hologram of the crosstalk detection symbol number 4 is reproduced, so that the reproduced image of the crosstalk detection symbol is as shown in FIG. 53 (e). Thus, the white level portion corresponding to the crosstalk detection symbol number 4 is detected with 100% brightness.

Similarly, when playback is performed at the tracking position F in FIG. 53 (j), white level portions corresponding to the crosstalk detection symbol numbers 4 and 5 are detected with a brightness of 50%, respectively, as shown in FIG. 53 (d). The
When playback is performed at the tracking position G in FIG. 53 (j), the white level portions corresponding to the crosstalk detection symbol numbers 3, 4, 6, and 7 are each 25% bright as shown in FIG. 53 (g). Detected.
When playback is performed at the tracking position H in FIG. 53 (j), white level portions corresponding to the crosstalk detection symbol numbers 4 and 7 are detected with 50% brightness, respectively, as shown in FIG. 53 (h).
When the reproduction is performed at the tracking position I in FIG. 53 (j), the white level portions corresponding to the crosstalk detection symbol numbers 4, 5, 7, and 8 are each 25% bright as shown in FIG. 53 (i). Detected.

  As described above, the relationship between the element hologram array and the tracking position is reflected in the reproduced image of the crosstalk detection symbol.

  FIG. 54 also shows a crosstalk detection symbol reproduction image example when the element holograms are arranged in a square lattice as shown in FIG. This is an example of tracking centering on the element hologram of the crosstalk detection symbol number 8.

When the reproduction is performed at the tracking position A in FIG. 54 (j), the intermediate position of the four element holograms to which the crosstalk detection symbol numbers 4, 5, 7, and 8 are assigned is reproduced. As shown in FIG. 54A, the reconstructed image is a reconstructed image in which the crosstalk detection symbols of the crosstalk detection symbol numbers 4, 5, 7, and 8 are combined, and the crosstalk detection symbol numbers 4, 5, 7, A white level portion corresponding to 8 is detected with a brightness of 25%.
When the reproduction is performed at the tracking position B in FIG. 54 (j), the intermediate position between the two element holograms of the crosstalk detection symbol numbers 5 and 8 is reproduced, so that the reproduction image of the crosstalk detection symbol is shown in FIG. As shown in b), the white level portions corresponding to the crosstalk detection symbol numbers 5 and 8 are detected with a brightness of 50%, respectively.
When the reproduction is performed at the tracking position C in FIG. 54 (j), the intermediate position of the four element holograms of the crosstalk detection symbol numbers 5, 3, 8, and 6 is reproduced. As shown in FIG. 54 (c), the white level portions corresponding to the crosstalk detection symbol numbers 5, 3, 8, and 6 are detected with a brightness of 25%, respectively.
When reproduced at the tracking position D of FIG. 54 (j), the intermediate position of the two element holograms of the crosstalk detection symbol numbers 7 and 8 is reproduced, so that the reproduced image of the crosstalk detection symbol is shown in FIG. As shown in d), the white level portions corresponding to the crosstalk detection symbol numbers 7 and 8 are detected with a brightness of 50%, respectively.
When reproduced at the tracking position E in FIG. 54 (j), the position directly above the element hologram of the crosstalk detection symbol number 8 is reproduced, so the reproduced image of the crosstalk detection symbol is as shown in FIG. 54 (e). Thus, the white level portion corresponding to the crosstalk detection symbol number 8 is detected with 100% brightness.

Similarly, when playback is performed at the tracking position F in FIG. 54 (j), white level portions corresponding to the crosstalk detection symbol numbers 8 and 6 are detected with 50% brightness, respectively, as shown in FIG. 54 (d). The
When playback is performed at the tracking position G in FIG. 54 (j), the white level portions corresponding to the crosstalk detection symbol numbers 7, 8, 1, and 2 are each 25% bright as shown in FIG. 54 (g). Detected.
When playback is performed at the tracking position H in FIG. 54 (j), white level portions corresponding to the crosstalk detection symbol numbers 8 and 2 are detected with a brightness of 50%, respectively, as shown in FIG. 54 (h).
When playback is performed at the tracking position I in FIG. 54 (j), the white level portions corresponding to the crosstalk detection symbol numbers 8, 6, 2, and 0 are each 25% bright as shown in FIG. 54 (i). Detected.

  As described above, the relationship between the element hologram array and the tracking position is reflected in the reproduced image of the crosstalk detection symbol.

FIG. 55 shows a representative example of tracking for an element hologram array of a square lattice, including cases other than the tracking position centering on the element holograms of the crosstalk detection symbol numbers 4 and 8 as shown in FIGS.
Similarly in FIG. 55, the crosstalk detection symbol number is indicated by a number in the element hologram. The tracking positions are indicated by broken circles indicated by A to Z and a to j.

As a representative example of tracking, considering the case of reproducing just above an element hologram (just tracking) and the case of reproducing an intermediate position of a plurality of element holograms (half tracking), as shown in FIG. There are a total of 36 tracking states of ~ j. A reproduced image in the case of the 36 tracking states is shown in FIG.
Although an individual description at each tracking position is avoided, as can be understood in the same manner as in the case of FIGS. 53 and 54, when the reproduced image of the crosstalk detection symbol is reproduced immediately above a certain element hologram, The white level portion corresponding to the crosstalk detection symbol number assigned to the element hologram is detected with 100% brightness. In the half tracking state for two element holograms, the reproduced image of the crosstalk detection symbol has a brightness of 50% in the white level portion corresponding to the two crosstalk detection symbol numbers assigned to the two element holograms. Is detected. Further, in the half tracking state for four element holograms, the reproduced image of the crosstalk detection symbol has a brightness of 50% in each of the white level portions corresponding to the four crosstalk detection symbol numbers assigned to the four element holograms. Is detected.
In reality, there is a delicate intermediate state between the just tracking state and the half tracking state. In such a case, it appears as a brightness balance of the white level portion of the crosstalk detection symbol.

Next, a reproduction image of a crosstalk detection symbol when element holograms are arranged in a staggered pattern as shown in FIG. 50B will be described.
In FIG. 57 (j), element holograms arranged in a staggered pattern are indicated by ◯, and crosstalk detection symbol numbers assigned by numbers are indicated. The tracking positions are indicated by broken circles A to I. FIG. 57 shows an example of tracking centering on the even-numbered element hologram of the crosstalk detection symbol number 4.

When the reproduction is performed at the tracking position A in FIG. 57 (j), the intermediate position of the three element holograms to which the crosstalk detection symbol numbers 0, 1, and 4 are assigned is reproduced. As shown in FIG. 57A, a reproduction image is obtained by combining the crosstalk detection symbols of the crosstalk detection symbol numbers 0, 1, and 4, and the white level corresponding to the crosstalk detection symbol numbers 0, 1, and 4 is obtained. Each part is detected with a brightness of 33%.
When reproduced at the tracking position B in FIG. 57 (j), the intermediate position between the two element holograms assigned with the crosstalk detection symbol numbers 1 and 4 is reproduced. As shown in FIG. 57B, the white level portions corresponding to the crosstalk detection symbol numbers 1 and 4 are detected with a brightness of 50%.
When the reproduction is performed at the tracking position C in FIG. 57 (j), the intermediate position of the three element holograms to which the crosstalk detection symbol numbers 1, 2, and 4 are assigned is reproduced. As shown in FIG. 57 (c), the white level portions corresponding to the crosstalk detection symbol numbers 1, 2, and 4 are detected at a brightness of 33%.
When the reproduction is performed at the tracking position D in FIG. 57 (j), the intermediate position of the three element holograms to which the crosstalk detection symbol numbers 0, 3, and 4 are assigned is reproduced. As shown in FIG. 57 (d), white level portions corresponding to crosstalk detection symbol numbers 0, 3, and 4 are detected at a brightness of 33%.
When the reproduction is performed at the tracking position E in FIG. 57 (j), the position directly above the element hologram to which the crosstalk detection symbol number 4 is assigned is reproduced. Therefore, the reproduction image of the crosstalk detection symbol is as shown in FIG. As in e), the white level portion corresponding to the crosstalk detection symbol number 4 is detected with 100% brightness.

Similarly, when playback is performed at the tracking position F in FIG. 57 (j), the white level portions corresponding to the crosstalk detection symbol numbers 2, 4, and 5 have a brightness of 33%, respectively, as shown in FIG. 57 (f). Detected.
When playback is performed at the tracking position G in FIG. 57 (j), white level portions corresponding to the crosstalk detection symbol numbers 4, 3, and 7 are detected with a brightness of 33%, respectively, as shown in FIG. 57 (g). The
When playback is performed at the tracking position H in FIG. 57 (j), white level portions corresponding to the crosstalk detection symbol numbers 4 and 7 are detected with 50% brightness, respectively, as shown in FIG. 57 (h).
When playback is performed at the tracking position I in FIG. 57 (j), white level portions corresponding to the crosstalk detection symbol numbers 4, 5, and 7 are detected with a brightness of 33%, respectively, as shown in FIG. 57 (i). The
As described above, the relationship between the element hologram array and the tracking position is reflected in the reproduced image of the crosstalk detection symbol.

FIG. 58 is an example of a reproduced image when the odd-numbered element hologram as the crosstalk detection symbol number 4 is centered in the same staggered lattice arrangement.
When the reproduction is performed at the tracking position A in FIG. 58 (j), the intermediate position of the three element holograms to which the crosstalk detection symbol numbers 1, 3, and 4 are assigned is reproduced. As shown in FIG. 58 (a), a cross-talk detection symbol number 1, 3, and 4 cross-talk detection symbols are combined to form a reproduced image, and a white level corresponding to the cross-talk detection symbol numbers 1, 3, and 4. Each part is detected with a brightness of 33%.
When reproduced at the tracking position B in FIG. 58 (j), the intermediate position between the two element holograms assigned with the crosstalk detection symbol numbers 1 and 4 is reproduced. As shown in FIG. 58B, the white level portions corresponding to the crosstalk detection symbol numbers 1 and 4 are detected with a brightness of 50%.
When the reproduction is performed at the tracking position C in FIG. 58 (j), the intermediate position of the three element holograms to which the crosstalk detection symbol numbers 1, 5, and 4 are assigned is reproduced. As shown in FIG. 58C, the white level portions corresponding to the crosstalk detection symbol numbers 1, 5, and 4 are detected with a brightness of 33%.
When the reproduction is performed at the tracking position D in FIG. 58 (j), the intermediate position of the three element holograms to which the crosstalk detection symbol numbers 3, 4, and 6 are assigned is reproduced. As shown in FIG. 57 (d), the white level portions corresponding to the crosstalk detection symbol numbers 3, 4, and 6 are detected with a brightness of 33%, respectively.
When reproduced at the tracking position E in FIG. 58 (j), the position directly above the element hologram to which the crosstalk detection symbol number 4 is assigned is reproduced, so that the reproduced image of the crosstalk detection symbol is shown in FIG. As in e), the white level portion corresponding to the crosstalk detection symbol number 4 is detected with 100% brightness.

Similarly, when playback is performed at the tracking position F in FIG. 58 (j), the white level portions corresponding to the crosstalk detection symbol numbers 5, 4, and 8 have a brightness of 33%, respectively, as shown in FIG. 58 (f). Detected.
When playback is performed at the tracking position G in FIG. 58 (j), white level portions corresponding to the crosstalk detection symbol numbers 4, 6, and 7 are detected with a brightness of 33%, respectively, as shown in FIG. 58 (g). The
When playback is performed at the tracking position H in FIG. 58 (j), white level portions corresponding to the crosstalk detection symbol numbers 4 and 7 are detected with 50% brightness, respectively, as shown in FIG. 58 (h).
When playback is performed at the tracking position I in FIG. 58 (j), white level portions corresponding to the crosstalk detection symbol numbers 4, 8, and 7 are detected at a brightness of 33%, respectively, as shown in FIG. 58 (i). The
As described above, the relationship between the element hologram array and the tracking position is reflected in the reproduced image of the crosstalk detection symbol.

  FIG. 59 shows a representative example of tracking for an element hologram arrangement in a staggered pattern. In the case of a staggered lattice, as shown in FIG. 59 (a), the element hologram columns to which the crosstalk detection symbol numbers 1, 4, and 7 are assigned are the columns of the crosstalk detection symbol numbers 0, 3, 6 and the crosstalk. An odd column (Odd Column) shifted by 0.5 element hologram intervals on the upper side from the detection symbol numbers 2, 5, and 8 and an even column (0.5 column hologram intervals shifted by the lower side as shown in FIG. 59 (b)). Even Column) is divided into two cases.

FIG. 60 shows reproduced images in each of 36 tracking states A to Z and a to j in the case of the odd number column in FIG. 59 (a).
In addition, FIG. 61 shows reproduced images in each of 36 tracking states A to Z and a to j in the case of the even-numbered column in FIG. 59B.
As can be understood in the same manner as in FIGS. 57 and 58, when the reproduced image of the crosstalk detection symbol is reproduced immediately above a certain element hologram, the crosstalk detection symbol assigned to that element hologram is used. The white level portion corresponding to the number is detected with 100% brightness. In the half tracking state for two element holograms, the reproduced image of the crosstalk detection symbol has a brightness of 50% in the white level portion corresponding to the two crosstalk detection symbol numbers assigned to the two element holograms. Is detected. Further, in the half tracking state for three element holograms, the reproduced image of the crosstalk detection symbol has a white level portion corresponding to the three crosstalk detection symbol numbers assigned to the three element holograms at a brightness of 33%. Is detected.
Of course, in this case as well, there is actually a delicate intermediate state between the just tracking state and the half tracking state. In such a case, it appears as a brightness balance of the white level portion of the crosstalk detection symbol.

As described above, the crosstalk detection symbol can be used to determine the tracking state during reproduction.
Then, as described with reference to FIG. 24, the crosstalk detection symbol, the main synchronization symbol, the physical page ID code symbol, and the logical page ID code symbol are combined to generate a page search symbol.
Also, the page search symbol and the group subsync are combined to generate a group main sync. A plurality of group main syncs are combined to form a physical page, and one element hologram is formed based on the physical page.
A hologram unit matrix 20 is formed by arranging the element holograms two-dimensionally.

[7. Effects of the embodiment]

In the above embodiment, the following effects can be obtained.
In the embodiment, after generating a data page from input data as a one-dimensional information sequence to be encoded, and further performing internal encoding and external encoding on the data page, a physical page as two-dimensional data Is generated, and this physical page is arranged in an element hologram arrangement, thereby realizing an encoding method suitable for information recording on the hologram recording medium.

In particular, in the sector division processing A2 and the EDC addition processing A3 in the scrambled page data generation unit 11, the data of the element hologram is divided into sectors and EDC is added to thereby improve the reliability of the final corrected data in units of sectors. I can judge.
In addition, by scrambling the logical page in the scramble process A4 in the scrambled page data generation unit 11, it is possible to make it impossible to estimate the recording data from the optically read physical page. This is suitable from the viewpoint of security of content data, computer data, etc. recorded in the hologram memory 3 and copyright protection.

Further, by adding an error correction code in units of logical pages in the data array conversion process B1 and the intra-page encoding process B2 in the inner page encoder 12, it becomes possible to detect and correct errors in units of logical pages.
In addition, as inter-page interleaving processing B3, inter-leave processing for completion within a logical page is performed, whereby symbol errors due to variations in brightness, geometrical deviation, etc. within the physical page can be distributed throughout the physical page.

  Further, by performing the inter-page encoding process C2 by the outer page encoder 13, it is not necessary to read out all pages when reproducing the hologram unit matrix 20 (when reproducing the hologram memory 3 on which the hologram unit matrix 20 is formed). For example, when 16 parity pages are added to 112 logical pages, if 77.5% of all logical pages have been read, erasure correction is performed on unread pages. All logical pages can be completely reproduced. As a result, efficient scanning at the time of reproduction can be realized and data reading performance can be improved.

  Also, by performing the page multiplexing process C3 with the outer page encoder 13, a closed stack type element hologram arrangement becomes possible, and the element hologram reading operation becomes easy.

  Further, the page ID generation processing D1 in the hologram unit matrix generation unit 14 causes the logical page ID uniquely assigned to the internally encoded page and the physical page ID uniquely assigned to the externally encoded page. When a physical page is reproduced from an element hologram, the physical reproduction position can be first ascertained by the physical page ID. Further, the reproduction apparatus side uses this physical page as a logical page. It is possible to grasp the logical reproduction position developed on the RAM.

In the two-dimensional modulation processing D6, as shown in FIG. 26, the two-dimensional code symbol includes a sub-sync pixel and a sub-guard pixel, as shown in FIG. One set of two-dimensional modulation tables (FIGS. 28 to 34) is generated by performing a rotational combination of a set of four symbols to generate a group R, and further generating a group subsync from four groups R as shown in FIG. 2 × 2 pixel sub-synchronization pattern can be generated from the two-dimensional symbol generated in (1). Depending on the sub-guard pixel, a white level region as a sub-synchronization pattern is clarified.
Furthermore, as shown in FIG. 38, a group subsync is composed of four groups R, the center is a subsynchronization pattern, and the main synchronization symbol is a 4 × 4 symbol configuration. The observed synchronization center position can be made uniform within the physical page.

  Also, the 30 patterns shown in FIG. 27 are excluded. That is, during the two-dimensional symbol generation process, conversion to a two-dimensional pattern in which white levels are continuous vertically / horizontally / diagonally is prohibited. As a result, the two-dimensional run length can be limited to 6 pixels or less, and the distinction from the continuous pattern of 8 pixels used in the main synchronization symbol can be facilitated.

The page search symbol is an integer multiple of the group subsync. The group subsync is 16 × 16 pixels, and the page search symbol is 32 × 32 pixels. That is, there are four page search symbols for the group subsync. In this way, even if the page search symbol is arranged at an arbitrary symbol position on the group main sync, the centroid position of the main sync symbol and the sub sync pattern can maintain regularity on both the vertical and horizontal axes. .
In addition, as described with reference to FIGS. 46 and 47, the even-numbered main synchronization symbol is square and the odd-numbered main synchronization symbol is rhombus. It can be easily detected.

As described with reference to FIGS. 50 to 61, each element hologram formed as the hologram unit matrix 20 includes a type of crosstalk detection symbol corresponding to the position on the array. Therefore, the tracking state can be determined based on the information of the crosstalk detection symbol detected at the time of reproduction.
In particular, adjacent element holograms must be assigned different crosstalk detection symbol numbers, that is, adjacent element holograms must be different crosstalk detection symbols, so that the tracking state during physical page playback is detected as crosstalk. It can be detected from the brightness variation of the symbol.

  Although the embodiment has been described above, the processing procedures and patterns described in the embodiment are merely examples, and various modifications are envisaged within the scope of the present invention.

It is explanatory drawing of the recording / reproducing of the hologram memory of embodiment of this invention. It is explanatory drawing of a structure and process of the hologram recording system of embodiment. It is explanatory drawing of the process of each part of the hologram recording system of embodiment. It is explanatory drawing of a process of the scrambled page data generation part of embodiment. It is explanatory drawing of the input data of embodiment. It is explanatory drawing of the pre-process page production | generation process of embodiment. It is explanatory drawing of the sector division | segmentation process of embodiment. It is explanatory drawing of the sector before a process of embodiment. It is explanatory drawing of the EDC addition process of embodiment. It is explanatory drawing of the scrambled data sector of embodiment. It is explanatory drawing of the page combination process of embodiment. It is explanatory drawing of the scrambled data page of embodiment. It is explanatory drawing of the process of the inner page encoder of embodiment. It is explanatory drawing of the data sequence conversion process of embodiment. It is explanatory drawing of the encoding process in a page of embodiment. It is explanatory drawing of the interleaving process in a page of embodiment. It is explanatory drawing of the internal coding page of embodiment. It is explanatory drawing of the process of the outer page encoder of embodiment. It is explanatory drawing of the page arrangement | sequence conversion process of embodiment. It is explanatory drawing of the encoding process between pages of embodiment. It is explanatory drawing of the page multiplexing process of embodiment. It is explanatory drawing of the interleaving process between pages of embodiment. It is explanatory drawing of the external encoding page of embodiment. It is explanatory drawing of a process of the hologram unit matrix production | generation part 14 of embodiment. It is explanatory drawing of the two-dimensional code symbol modulation of embodiment. It is explanatory drawing of the two-dimensional code symbol of embodiment. It is explanatory drawing of the two-dimensional code symbol which embodiment excludes. It is explanatory drawing of the two-dimensional modulation table of embodiment. It is explanatory drawing of the two-dimensional modulation table of embodiment. It is explanatory drawing of the two-dimensional modulation table of embodiment. It is explanatory drawing of the two-dimensional modulation table of embodiment. It is explanatory drawing of the two-dimensional modulation table of embodiment. It is explanatory drawing of the two-dimensional modulation table of embodiment. It is explanatory drawing of the two-dimensional modulation table of embodiment. It is explanatory drawing of the group R production | generation of embodiment. It is explanatory drawing of the group subsync production | generation of embodiment. It is explanatory drawing of the page search symbol of embodiment. It is explanatory drawing of the group main sink of embodiment. It is explanatory drawing of the physical page of embodiment. It is explanatory drawing of the physical page of the preamble of embodiment. It is explanatory drawing of the physical page of the increment data of embodiment. It is explanatory drawing of the physical page of the random data of embodiment. It is explanatory drawing of the physical page of 00h fixed data of embodiment. It is explanatory drawing of the physical page of FFh fixed data of embodiment. It is explanatory drawing of the hologram unit matrix of embodiment. It is explanatory drawing of the main synchronous symbol of embodiment. It is explanatory drawing of the main synchronous symbol and reproduction | regeneration signal of embodiment. It is explanatory drawing of the logical page ID code symbol of embodiment. It is explanatory drawing of the physical page ID code symbol of embodiment. It is explanatory drawing of the element hologram arrangement | sequence of embodiment. It is explanatory drawing of the crosstalk detection symbol of embodiment. It is explanatory drawing of the crosstalk detection symbol of each number of embodiment. It is explanatory drawing of the reproduced image of the crosstalk detection symbol of embodiment. It is explanatory drawing of the reproduced image of the crosstalk detection symbol of embodiment. It is explanatory drawing of the tracking position of embodiment. It is explanatory drawing of the reproduced image of the crosstalk detection symbol of embodiment. It is explanatory drawing of the reproduced image of the crosstalk detection symbol of embodiment. It is explanatory drawing of the reproduced image of the crosstalk detection symbol of embodiment. It is explanatory drawing of the tracking position of embodiment. It is explanatory drawing of the reproduced image of the crosstalk detection symbol of embodiment. It is explanatory drawing of the reproduced image of the crosstalk detection symbol of embodiment.

Explanation of symbols

3 hologram memory, 10 recording system, 11 scrambled page data generation unit, 12 inner page encoder, 13 outer page encoder, 14 hologram unit matrix generation unit, 20 hologram unit matrix

Claims (8)

In a hologram recording apparatus that converts recording information into a physical page as two-dimensional page data, records the physical page as an element hologram,
Two-dimensional modulation means for converting binary data for each predetermined unit as recording information into a two-dimensional code symbol, synthesizing the two-dimensional code symbol, and generating a group subsync including a sub-synchronization pattern;
Physical page generation means for generating a group main sync using the group subsync generated by the two-dimensional modulation means and a main synchronization symbol, and generating the physical page by a plurality of the group main syncs;
Element hologram arraying means for generating an element hologram array by converting the physical page into an element hologram,
A hologram recording apparatus comprising: The two-dimensional modulation means is
Generating the two-dimensional code symbol by setting a specific corner pixel in the two-dimensional code symbol of N × N pixels as a sub-synchronous pixel;
By combining the four two-dimensional code symbols as a set and performing the necessary rotation processing for each of the four two-dimensional code symbols, each sub-synchronization pixel is positioned at the four corners. A 2N × 2N pixel rotation group
Further, the four rotation groups are combined in two horizontal groups and two vertical groups, and the four sub-sync pixels collected in the central 2 × 2 pixels after the combination are the sub-sync pattern. The hologram recording apparatus according to claim 1, wherein the group subsync is generated. The necessary rotation processing performed by the two-dimensional modulation means for each of the four two-dimensional code symbols is as follows:
The first 2D code symbol is unrotated,
Rotate the second 2D code symbol 90 ° to the right,
Rotate the third two-dimensional code symbol by 180 °,
Rotate the fourth 2D code symbol 90 degrees to the left,
The hologram recording apparatus according to claim 2, wherein:   The two pixels adjacent to the sub-synchronization pixel having a specific corner in the two-dimensional code symbol of N × N pixels are sub-guard pixels that protect the sub-synchronization system. Hologram recording device. The physical page generating means arranges the group main sync by arranging a page search symbol having the main sync symbol and an integer multiple of the group sub sync in the group sub sync array. Generate
2. The hologram recording apparatus according to claim 1, wherein the physical page is generated by two-dimensionally arranging a plurality of the group main syncs. The two-dimensional modulation means generates the two-dimensional code symbol as a pattern in which a black level and a white level are assigned to each of N × N pixels,
A two-dimensional code symbol of a pattern selected according to a binary data value in a predetermined unit is generated from patterns excluding a pattern in which white levels are continuous vertically, horizontally, or diagonally. 1. The hologram recording apparatus according to 1.   7. The hologram recording apparatus according to claim 6, wherein the main synchronization symbol is configured by a white level pixel group having a size larger than the two-dimensional code symbol of the N × N pixels. As a hologram recording method for converting the recording information into a physical page as two-dimensional page data and recording the physical page as an element hologram,
A two-dimensional modulation step of converting binary data for each predetermined unit as recording information into a two-dimensional code symbol, synthesizing the two-dimensional code symbol, and generating a group subsync including a sub-sync pattern;
A physical page generation step of generating a group main sync using the group subsync generated in the two-dimensional modulation step and a main synchronization symbol, and generating a physical page with the plurality of group main syncs;
An element hologram array step for generating an element hologram array by converting the physical page into an element hologram; and
A hologram recording method comprising:

Images