Patent Application
20070047042
The present invention contains subject matter related to Japanese Patent Application JP 2005-249082 filed in the Japanese Patent Office on Aug. 30, 2005, the entire contents of which being incorporated herein by reference.
1. Field of the Invention
The present invention relates to a hologram recording apparatus and a hologram recording method, in which an encoding process is conducted for audio information such as sound or music, image information such as a still image or a moving image, or information such as a text file and then the information is recorded on a hologram recording medium in a sheet shape, for example, as a plurality of element holograms, particularly to an information encoding scheme of a hologram recording apparatus and a hologram recording method.
2. Description of the Related Art
Patent Reference 1: Japanese Patent No. 2833975
For an exemplary scheme to record information on a recording medium in a sheet shape, a linear code or a two-dimensional code is named, typified by a bar code, a QR code, dot code, etc. However, these information recording media have about a few tens to a few kilobytes of an information amount capable of recording per unit area, which is very low. This is because the recording resolution of simple grayscale printing of an image has physical limitations.
In addition, for a similar recording medium in a sheet shape, a hologram recording medium is also known which records various items of data with interference fringes of object beams and reference beams. It is also known that the hologram recording medium dramatically improves recording density to allow a significant increase in capacity. For example, it is considered to be useful as a large capacity storage medium for computer data and AV (Audio-visual) contents data such as audio and video.
In recording data on the hologram recording medium, data is imaged as two-dimensional page data. Then, the imaged data is displayed on a liquid crystal panel, for example, the light transmitted through the liquid crystal panel is object beams, that is, the object beams to be an image of two-dimensional page data, and the beams are applied onto the hologram recording medium. In addition to this, reference beams are applied onto the hologram recording medium at a predetermined angle. At this time, interference fringes generated by the object beams and the reference beams are recorded as a single element hologram in a strap or in a dot. In other words, a single element hologram is what records a single item of two-dimensional page data.
For example, a hologram memory in a sheet shape is considered, and a system is considered in which computer data and AV contents data are recorded and general users use a reconstruction apparatus as a hologram reader to acquire data recorded on a hologram memory.
The hologram memory in a sheet shape is a memory that records a plurality of element holograms on the plane as the surface of a medium as though the element holograms are paved thereon, in which the hologram reader is faced to the surface of the medium to read the recorded data as the individual element holograms.
When hologram technology is used, an amount of information per unit area for recording can be improved dramatically as compared with normal printing. However, the information encoding scheme used for the bar code or QR code scheme has the purpose of recording information on normal two-dimensional printing media, which has no consideration for applications to hologram recording.
It is desirable to provide an encoding scheme preferable for information recording on a hologram recording medium, particularly to provide an information encoding scheme preferable for recording a large amount of information on a medium in a sheet shape, on which so-called holograms are printed.
A hologram recording apparatus according to an embodiment of the invention is a hologram recording apparatus which forms information into element holograms for recording, including: data page generating means for forming a two-dimensional matrix from a linear information sequence that is an encoding target and generates a data page; inner page encoding means for conducting encoding that is completed in the data page to generate an inner encoded page; interpage encoding means for conducting encoding over the inner encoded pages to generate an outer encoded page; and element hologram matrix generating means for forming the outer encoded page into a 2D code symbol, generating a physical page including the 2D code symbol, and continuously forming the physical page into element holograms to generate an element hologram matrix.
In addition, the data page generating means conducts: a raw page creation process which forms a two-dimensional matrix from a linear information sequence that is an encoding target and generates a raw page; a sector splitting process which splits the raw page into raw sectors that are units of error detection; an error detecting code adding process which adds an error detecting code to the raw sector to form sectors with error detecting codes; a scramble process which scrambles the sectors with error detecting codes to generate scrambled data sectors; and a page joining process which joins the scrambled data sectors to generate a scrambled data page to output the scrambled data page as a data page.
In addition, the inner page encoding means conducts: a data array transform process which transforms the data page outputted from the data page generating means to an arrangement that allows multidimensional encoding and generates an information data block; an inner page encoding process which performs multidimensional encoding for the information data block to generate a code data block; an inner page interleave process which rearranges the inside of the code data block in accordance with a predetermined rule to generate an interleaved code data block; and a data array inverse transform process which transforms the interleaved code data block to a page arrangement equivalent to the data page to generate an inner encoded page.
In addition, the interpage encoding means conducts: a page arrangement transform process which transforms the inner encoded page outputted from the inner page encoding means to a page arrangement that allows interpage encoding and generates an information page block; an interpage encoding process which performs interpage encoding for the information page block to generate a code page block; a page duplication process which duplicates the code page block to multiple blocks to generate duplicated page blocks; an interpage interleave process which rearranges the duplicated page blocks in accordance with a predetermined rule to generate interleaved duplicated blocks; and a page arrangement retransform process which transforms the interleaved duplicated blocks to a page arrangement equivalent to the inner encoded page to generate an outer encoded page.
In addition, the element hologram matrix generating means conducts: a first two-dimensional modification process which two-dimensionally modifies the outer encoded page outputted from the interpage encoding means to generate a two-dimensional code symbol; a page ID creation process which generates a logical page ID for the inner encoded page and generates a physical page ID for the outer encoded page; a page ID encoding process which adds an error correction parity to the logical page ID and the physical page ID to generate a logical page ID code and a physical page ID code; a second two-dimensional modification process which two-dimensionally modifies the logical page ID code and the physical page ID code to generate a logical page ID code symbol and a physical page ID code symbol; a synchronization signal creation process which creates a main sync symbol; a crosstalk detect symbol creation process which creates a crosstalk detect symbol that detects crosstalk between adjacent element holograms; a page search symbol creation process which joins the logical page code symbol, the physical page code symbol, the main sync symbols and the crosstalk detect symbol to one another to generate a page search symbol; a physical page creation process which joins the two-dimensional code symbol to the page search symbol to generate a physical page; and an element hologram matrixing process which continuously forms the physical pages into element holograms to form an element hologram matrix.
A hologram recording method according to an embodiment of the invention includes the steps of: forming a two-dimensional matrix from a linear information sequence that is an encoding target and generating a data page; conducting encoding that is completed in the data page and generating an inner encoded page; conducting encoding over the inner encoded pages to generate an outer encoded page; and forming the outer encoded page into a two-dimensional code symbol, generates a physical page including the two-dimensional code symbol, and continuously forming the physical page into element holograms to generate an element hologram matrix.
More specifically, according to an embodiment of the invention, a data page is generated from a linear information sequence that is an encoding target, and inner encoding and outer encoding are conducted for the data page. Then, after outer encoding, a physical page as two-dimensional data is generated from the data to form the physical page into an element hologram matrix.
According to an embodiment of the invention, the data page is generated from the linear information sequence that is an encoding target, inner encoding (inner page encoding) and outer encoding (interpage encoding) are conducted for the data page to generate the physical page as two-dimensional data, and the physical page is formed into the element hologram matrix, whereby an encoding scheme can be implemented which is preferable for information recording on a hologram recording medium.
Particularly, in the data page creation process, data to be element holograms is split into sectors to add the error detecting code thereto, whereby the reliability of finally corrected data can be determined in units of sectors.
In addition, the scramble process is conducted for the sectors added with the error detecting codes. More specifically, the logical page is scrambled. When this is done, the descriptions of the recorded data cannot be read easily from the physical page optically read in reconstruction. Therefore, it is preferable in view of the security and copyright protection of contents data and computer data to be recorded on a hologram recording medium.
In addition, in the inner page encoding process, an error correcting code is added in units of the logical pages. Therefore, error detection and correction can be done in units of the logical pages.
In addition, the interleave process which is completed inside the logical page is conducted to distribute symbol error caused by the intensity fluctuations and geometrical shifts in the physical page throughout the physical page.
In addition, inter page encoding is conduced in the interpage encoding process to eliminate a necessity to read all pages in reading. More specifically, even though all the pages are not read, loss correction is conducted for the unread pages to reproduce all the logical pages. Accordingly, the implementation of efficient scan and improved data read performance in reconstruction can be intended.
In addition, the page duplication process is conducted to allow a closed stack element hologram matrix, and thus the read operation of element holograms can be facilitated.
In addition, in the hologram matrix creation process, the logical page ID uniquely allocated to the inner encoded page and the physical page ID uniquely allocated to the outer encoded page are added, whereby the physical reconstruction position can be first grasped by the physical page ID in reconstruction of the physical page from the element holograms, and the logical reconstruction position can be grasped at which the physical page is developed as the logical page on the memory in the reconstruction apparatus. Accordingly, the conditions to read the element holograms can be properly established.
Hereinafter, an embodiment of the invention will be described in the following order.
First, the basic operations of recording and reconstruction of a hologram memory 3 will be described with reference to
One item of data DT as an encoded unit is converted into image data in a two-dimensional bar code, for example, as shown in the drawing, and is displayed as an image of two-dimensional page data on a liquid crystal panel 1.
Laser beams L1 outputted from a predetermined light source and formed into parallel light beams, for example, pass through the liquid crystal panel 1 on which the image of two-dimensional page data is displayed, and then the beams are turned to object beams L2 as an image of the two-dimensional page data.
The object beams L2 are condensed by a condenser lens 2, and are gathered as a spot on the hologram memory 3.
At this time, onto the hologram memory 3, record reference beams L3 are applied at a predetermined angle. Thus, the object beams L2 interfere with the reference beams L3, and an element hologram in dots is recorded by interference fringes thereof.
In addition, as described above, when the condenser lens 2 is used, data recorded as the element hologram is a Fourier image of an image of the recorded data due to the effect of Fourier transform by the condenser lens 2.
As described above, a single element hologram is recorded on the hologram memory 3. Data DT of an encode unit is sequentially converted into two-dimensional page data in the similar manner, displayed on the liquid crystal panel 1, and recorded as an element hologram one by one.
In recording each of the element holograms, the position of the hologram memory 3 (hologram material) is moved by a transport mechanism, not shown, (or a recording optical system is moved) , the recording position of the element holograms is slightly shifted on the plane of the hologram memory 3. Thus, recording is conducted such a way that a plurality of element holograms are arranged on the hologram memory 3 in a sheet shape, for example, in the plane direction. For example, in
For the hologram memory 3 on which the element holograms are thus recorded, reconstruction is performed as described in
Onto the hologram memory 3, reconstruction reference beams L4 are applied at the same application angle as that in recording. When the reconstruction reference beams L4 are applied, a reconstructed image can be obtained that is recorded as the element holograms. In other words, an image of two-dimensional page data appears at the place conjugated with the liquid crystal panel 1 when recorded. It is sufficient to read the image by the imager 5.
More specifically, reconstructed image beams L5 from the hologram memory 3 are formed into parallel light beams by the collimator lens 4, and enter the imager 5 formed of a CCD imaging device array or a CMOS imaging device array, for example. The Fourier image on the hologram memory 3 is transformed in inverse Fourier transform by the collimator lens 4, and formed into an image of two-dimensional page data. Thus, the reconstructed image as the image of two-dimensional page data is read by the imager 5.
The imager 5 generates a reconstructed image signal as an electrical signal in accordance with the reconstructed image. A decoding process is conducted for the reconstructed image signal, whereby original data is obtained, that is, data before converted to the two-dimensional page data for the purpose of recording.
A plurality of the element holograms on the hologram memory 3 is similarly, continuously read, whereby the recorded original contents data can be reproduced.
In addition, for a recording scheme for the hologram memory 3 like this, angle multiplexing recording is known. Angle multiplexing is a scheme that the angle of the record reference beams L3 is varied to record element holograms at the same positions on the plane in a multiplexed manner.
For example, when a single element hologram is recorded as shown in
In other words, multiplexed recording can be performed using the plane of the hologram memory 3 as multiple planes by varying the angle of the record reference beams L3, whereby the recording capacity can be increased greatly. For example, it is an image that the element hologram matrix plane as shown in
In the reconstruction of the recorded hologram memory 3 after angle multiplexing recording, it is sufficient that the reconstruction reference beams L4 are applied at the same angle as each angle of the record reference beams when recorded. More specifically, the element hologram that is recorded by applying the record reference beams L3 at a first angle can be read by applying the reconstruction reference beams L4 at the same first angle, and the element hologram that is recorded by applying the record reference beams L3 at a second angle can be read by applying the reconstruction reference beams L4 at the same second angle.
In addition, the hologram memory 3 on which data is recoded with element holograms described above can be easily copied in mass production by contact copy.
Therefore, the hologram memory 3 on which element holograms are recorded on a hologram material as shown in
For example, when such a system is considered that computer data or AV contents data is recorded on a hologram recording medium for wide distribution as well as a general user uses a reconstruction apparatus (a hologram reader 20) to acquire data recorded on the hologram memory 3, a hologram master medium is created as shown in
2. Outline of Overall Data Encoding Processes
Hereinafter, data encoding processes for recording data on the hologram memory 3 will be described.
An input data stream shown in
For input data, various items of data can be considered such as audio contents, video contents, computer programs or computer data.
A recording system 10 is configured to have a scrambled data page generator 11 which conducts a data page creation process for input data supplied as a record target, an inner page encoder 12 which conducts an inner page encoding process, an outer page encoder 13 which conducts an interpage encoding process, and a the hologram unit matrix generator 14 which conducts a hologram matrix creation process to create a hologram memory 3.
The input data to be target data for encoding has the size of m×n bytes as a unit. Each item of input data in a unit of m×n bytes is expressed by D[0], D[1], . . . , D[mn−1], where m is the number of pages of data for encoding, and n is the number of items of data per page.
The input data is inputted to the scrambled data page generator 11. The scrambled data page generator 11 conducts a scramble process for the input data, and creates m pages of data, scrambled data pages SDP0, SDP1, . . . , SDPm−1. Then, it outputs them as a scrambled data page stream.
The scrambled data pages SDP0, SDP1, . . . , SDPm−1 are inputted to the inner page encoder 12. The inner page encoder 12 conducts the inner page encoding process for the inputted scrambled data pages, and creates m pages of data, inner encoded pages IEP0, IEP1, . . . , IEPm−1. Then, it outputs them as an inner encoded page stream.
The stream data of the inner encoded pages IEP0, IEP1, IEPm−1 is inputted to the outer page encoder 13. The outer page encoder 13 conducts the interpage encoding process for the inputted inner encoded pages, and creates x·y·z pages of data, outer encoded pages OEP0, OEP1, . . . , OEPxyz−1. Then, it outputs them as an outer encoded page stream.
The stream data of the outer encoded pages OEP0, OEP1, OEPxyz−1 is inputted to the hologram unit matrix generator 14. The hologram unit matrix generator 14 conducts an element hologram process for the outer encoded pages, and creates a hologram unit matrix 20 having an xy unit of element holograms HU (0, 0), . . . , HU (x−1, y−1) recorded. The hologram unit matrix is a matrix that element holograms are recorded on a hologram material in the operation shown in
In the specification, the hologram unit matrix 20 is used as a general term meaning that a plurality of element holograms (=hologram units) is arranged on a hologram material.
3. Data Page Creation Process
The data page creation process in the scrambled data page generator 11 will be described in detail.
The raw page creation process A1 is conducted for the input data to create raw pages.
In the sector splitting process A2, raw sectors are created from the raw pages.
In the EDC adding process A3, sectors with EDC are created from the raw sectors.
In the scramble process A4, scrambled data sectors are created from the sectors with EDC.
In the page joining process A5, scrambled data pages are created from the scrambled data sectors.
Each of the processes will be described sequentially.
First, the raw page creation process A1 is conducted for raw bytes as input data D[0], D[1], . . . , D[mn−1]]. The raw bytes mean data before processed. As shown in
Subsequently, in the sector splitting process A2, each of the raw pages, Raw Page [0], Raw Page [1], . . . , Raw Page [m−1] is split into s sectors of raw sectors. More specifically, as shown in
All the raw pages are each split into s sectors of raw sectors, and thus m×s sectors of raw sectors, Raw Sector [0] [0], . . . , Raw Sector [m−1] [s−1] are formed, which are shown in
The raw sector is a processing unit of an EDC (error detecting code), described later, and it is configured of t bytes (t=n/s). For example, the raw page Raw Page [0] is formed of t bytes of input data D[0], . . . , D[t−1].
Subsequently, in the EDC adding process A3, the EDC (error detecting code) is added to each of the raw sectors, Raw Sector [0][0], . . . , Raw Sector [m−1] [s−1].
Subsequently, in the scramble process A4, the scramble process is conducted for each of the sectors with EDC, Sector with EDC [0] [0], Sector with EDC [0] [1], . . . , Sector with EDC [m−1] [s−1], and scrambled data sectors shown in
As apparent from
For example, input data D[0], . . . , D[t−1] and the EDC parities E[0], E[1], . . . , E[u−1] configuring the sector with EDC Sector with EDC [0] [0] in
The other sectors with EDC also undergo the scramble process. Therefore, m×s of the scrambled data sectors, Scrambled Data Sector [0] [0], Scrambled Data Sector [0] [1], Scrambled Data Sector [m−1] [s−1] are formed.
The page joining process A5 is conducted for the scrambled data sector. In this case, as shown in
More specifically, the scrambled data sectors, Scrambled Data Sector [0] [0], . . . , Scrambled Data Sector [0] [s−1] are joined to create a scrambled data page SDP0. Similarly, the scrambled data sectors are continuously joined to form scrambled data pages up to a scrambled data page SDP [m−1].
Each of the scrambled data pages is configured of r bytes, where r=n+u×s bytes.
As described in
4. Inner Page Encoding Process
For the scrambled data pages SDP0, SDP1, . . . , SDPm−1 acquired in the data page creation process in the scrambled data page generator 11, the inner page encoding process is conducted in the inner page encoder 12.
In the data array transform process B1, information data blocks are formed from the scrambled data page SDP.
In the inner page encoding process B2, code data blocks are formed from the information data block.
In the inner page interleave process B3, an interleaved code data block is formed from the code data block.
In the data array inverse transform process B4, an inner encoded page is formed from the interleaved code data blocks.
Each of the processes will be described sequentially.
The inputted scrambled data pages SDP0, SDP1, . . . , SDPm−1 are inputted to the inner page encoder 12, and the arrangement thereof is converted to create an information data block for inner page encoding in the data array transform process B1.
For example,
As described above, the arrangement of each of the scrambled data pages SDP0, SDP1, . . . , SDPm−1 is transformed to form information data blocks, Info Data Block [0], Info Data Block [1], . . . , Info Data Block [m−1].
In addition, the notations of I[α] [β] [γ] are as follows: α is a column index (column number) , β is a row index (row number) and γ is a page index (page number)
The correspondence between the scrambled data page data SD and I[α] [β] [γ] converted in array is I[α] [β] [γ]=SD[a·b·γ+a·β+−α].
Subsequently, in the inner page encoding process B2, the correction parity is added to the information data block (Info Data Block) to create a code data block.
For example, to the information data block Info Data Block [0] shown in
Similarly, parities P are also added to the other information data blocks. Therefore, m blocks of code data blocks, Code Data Block [0], . . . , Code Data Block [m−1] are formed.
For the created code data block Code Data Block [0], Code Data Block [m−1], the interleave process is conducted which is completed inside the page in the inner page interleave process B3.
For example, data I[0] [0] [0], . . . , P[i−1] [j−1] [0] configuring the Code Data Block [0] shown in
In the data array inverse transform process B4, m blocks of interleaved code data blocks created as shown in
For example, the arrangement of an interleaved code data block [0] shown in
As described in
5. Interpage Encoding Process
For the inner encoded pages IEP0, IEP1, . . . , IEPm−1 acquired in the inner page encoding process done by the inner page encoder 12, the interpage encoding process is conducted in the outer page encoder 13.
In the page arrangement transform process C1, information page blocks are created from the inner encoded pages IEP.
In the interpage encoding process C2, code page blocks are created from the information page blocks.
In the page duplication process C3, duplicated page blocks are created from the code page blocks.
In the interpage interleave process C4, interleaved duplicated blocks are created from the duplicated page blocks.
In the page arrangement retransform process C5, outer encoded pages are created from the interleaved duplicated blocks.
Each of the processes will be described sequentially.
The inner encoded pages IEP0, IEP1, . . . , IEPm−1 are inputted to the outer page encoder 13, and the arrangements thereof are transformed to create information page blocks for interpage encoding in the page arrangement transform process C1.
Subsequently, in the interpage encoding process C2, an interpage correction parity page is added to the information page block, and a code page block is created.
For the code page block, in the page duplication process C3, each page is duplicated into a multiple pages to create a duplicated page block.
For duplication, duplication is conducted such a way that each of the code pages IEP[0], IEP[1], . . . , IEP[f−1], OPP[0], . . . , OPP[g−1] in the first row among e pages in column shown in
Similarly, duplication is conducted such a way that each of the code pages IEP[f], IEP[f+1], . . . , IEP[f+(f−1)]) OPP[g], . . . , OPP[g+(g−1)] in the second row among e pages in column shown in
Hereinafter, duplication is similarly conducted to create e×q pages in column of a duplicated page block shown in
For the duplicated page block, the interleave process crossing over pages is conducted in the interpage interleave process C4, interleaved duplicated blocks are created as shown in
In
In the page block of each rayer, the individual interleaved pages are represented by IDP[x] [y] [z]. For example, individual pages in Rayer[0] is represented by IDP[0] [0] [0], . . . , IDP[x−1] [y −1] [z].
As described above, the page arrangements of the interleaved duplicated blocks are again transformed into units of pages in the page arrangement retransform process C5, and outer encoded pages OEP are created.
The page arrangements of the interleaved duplicated blocks shown in
The outer encoded pages OEP0, . . . , OEPxyz−1 are outputted from the outer page encoder 13 as described in
6. Hologram Matrix Creation Process
The outer encoded pages OEP0, OEP1, . . . , OEPxyz−1 are supplied to the hologram unit matrix generator 14 to form a hologram unit matrix 20 on a hologram material that finally forms a hologram memory or a master medium thereof.
As shown in
In addition, in the hologram unit matrix generator 14, a physical page ID and a logical page ID are created in the page ID creation process D1. The physical page ID and the logical page ID are coded in the page ID encoding process D2, and formed into a physical page ID code and a logical page ID code.
Moreover, the second two-dimensional modification process D5 is conduced for the physical page ID code and the logical page ID code, and are converted into physical page ID code symbols and logical page ID code symbols as two-dimensional patterns.
In addition, in the hologram unit matrix generator 14, in the synchronization signal creation process D3, main sync symbols are created which detect the slice position of the 2D symbol.
In addition, in the hologram unit matrix generator 14, crosstalk detect symbols are created in the crosstalk detect symbol creation process D4.
Then, the physical page ID code symbols, the logical page ID code symbols, the main sync symbols, and the crosstalk detect symbols are synthesized in the page search symbol creation process D7, and page search symbols are created as two-dimensional patterns.
The page search symbols are synthesized with the 2D code symbols in the physical page creation process D8 to create physical pages. Then, each of the physical pages is recorded on the hologram material as element holograms in the element hologram matrixing process D9, and the hologram unit matrix 20 is formed on which element holograms HU (0, 0), . . . , HU (x−1, y−1) are recorded as shown in
Each of the processes in the hologram unit matrix generator 14 will be described.
In the two-dimensional modification process D6, the outer encoded pages OEP0, OEP1, . . . , OEPxyz−1from the outer page encoder 13 are converted into 2D code symbols.
The byte data as eight bits of binary codes D0 to D7 shown in (a) in
For an example, a value “01011010” is shown in (c) in
Here, in order to represent eight bits of byte data, the 2D code symbols below are necessary.
28=256 [symbols].
Here, the number of types of three combinations among 13 pixels is determined, where “C” denotes combination.
13C3=286 [symbols]
256 different combinations can be represented with 13 pixels or greater for the number of pixels of 2D code symbols.
Consequently, three pixels as 4×4−13=3 can be allocated for the purposes other than the representation of byte data.
Then, as shown in
In addition, pixels Pb and Pe are assigned as sub-sync guard pixels (SS-Guard Pixel) which guard a sub-sync pixel. The pixels Pb and Pe are set to the black level all the time.
Then, pixels P0, . . . , Pa, Pc, Pd of the remaining 13 pixels are assigned as code pixels. Three pixels among 13 pixels are set to the white level, and 10 pixels are set to the black level in accordance with byte data that is desired to be modified.
Here, 13C3−28=286−256=30 [symbols], and then 30 non-code symbols can be defined.
256 two-dimensional patterns except 30 symbols are allocated to byte data values “00h” to “FFh”.
For example, as shown in
In other words, as shown in
Although one byte of data is converted into 4×4 pixels of a 2D code symbol as described above, a group R (Group-R: group rotated) is created from four bytes, that is, four of 4×4 pixels of 2D code symbols.
Each of the byte data is converted into 4×4 pixels of a two-dimensional pattern in accordance with the modification table. Two-dimensional patterns created in accordance with the values of the byte data A, B, C and D are shown in (e), (f), (g) and (h) in
To the four two-dimensional patterns, the rotating manipulation is applied as follows.
The two-dimensional pattern of byte data A: not rotated as shown in (i) in
The two-dimensional pattern byte data B: rotated at an angle of 90 degrees rightward as shown in (j) in
The two-dimensional pattern byte data C: rotated at an angle of 180 degrees as shown in (k) in
The two-dimensional pattern byte data D: rotated at an angle of 90 degrees leftward as shown in (1) in
Then, four symbols shown in (i), (j), (k) and (1) in
The group R is formed from four bytes of data as described above. Four patterns of the groups Rare synthesized to create a group sub-sync (Group-SS: Group Sub-Sync).
As (a), (b), (c) and (d) in
These four groups R are joined to create 16×16 pixels of a group sub-sync as shown in (e) in
In addition, to the pixels Pf of other byte data A, B, D, E, F, G, J, K, L, M, 0 and P, the black level is assigned to suppress the frequency of white pixels on the group sub-sync.
The group sub-syncs are formed in the two-dimensional modification process D6, and are supplied to the physical page creation process D8 shown in
More specifically, in the two-dimensional modification process D6, the pixel Pf at a specific corner is established as a sub-sync pixel in 4×4 pixels of a 2D code symbol, and then 2D code symbol is created.
Subsequently, four 2D code symbols are formed in one set, a necessary rotation process is conducted for each of four 2D code symbols, and then they are synthesized, whereby a group rotated (group R) is created in which each of the sub-sync pixels Pf is positioned at four corners.
Moreover, four groups rotated (groups R) are arranged in a form of two groups in row and two groups in column, and then synthesized. The group sub-sync is created such a way that four sub-sync pixels Pf to be the white level gathered in 2×2 pixels at the center after synthesized to be a sub-sync pattern.
On the other hand, a page search symbol is created in the page search symbol creation process D7 shown in
Each symbol in the page search symbol will be described later. In the physical page creation process D8, the page search symbol is synthesized with the group sub-sync to form a group main-sync (Group-MS) , and a set of the groups main-sync is a physical page.
A group main-sync is shown in (a) in
However, in this case, 64 groups sub-sync can be arranged. 2×2 groups of groups sub-sync (32×32 pixels) at a given position are blank to insert a page search symbol.
More specifically, a page search symbol having a main sync symbol is arranged in the group sub-sync arrangement. The page search symbol is configured of pixels that are an integral multiple of 16×16 pixels of a group sub-sync.
Then, as described above, the group main-sync thus configured is formed of 128×128 pixels, including 60 groups sub-sync and a single page search symbol.
As described above, a single group sub-sync has 16×16 pixels, and includes 16 bytes of items of one byte data represented by 16 pixels. Therefore, the group main-sync includes 16×60=960 bytes (960 symbols) as data.
In addition, in the group main-sync, the positions of center of gravity of the main sync symbol and the sub-sync pattern (=four pixels at the white level at the center of the group sub-sync) maintain regularity both in the column direction and in the row direction.
The group main-sync like this is further arranged in the two-dimensional plane to be a physical page.
Here, an example is shown in which the groups main-sync Group-MS[0] [0], . . . , Group-MS[p−1] [q−1] are arranged to form a physical page in such a way that p groups are arranged in the row direction and q groups are arranged in the column direction.
In the physical page creation process D8 shown in
In addition, in the physical page shown in
In the odd numbered group main-sync and the even numbered group main-sync, the main sync symbols in the page search symbols are varied. For example, since the page search symbol shown in
Here, examples of the physical pages are shown in
As shown in
Subsequently, the main sync symbols formed in the synchronization signal creation process D3 shown in
The main sync symbol for the even numbered group main-sync shown in
The main sync symbol for the odd numbered group main-sync shown in
As described above, the main sync symbols are configured of a group of white level pixels in the size greater than 4×4 pixels of a 2D code symbol.
As apparent from the drawing, depending on the patterns of the odd numbered and the even numbered main sync symbols, different reconstruction waveforms are obtained in accordance with scan positions. In other words, the high level width of the reconstruction waveform for each of the main sync symbols is determined to easily detect the reconstruction position (the scan position) for the recorded pattern.
In addition, for the main sync symbols, two types of examples are taken shown in
Next, the physical page ID code symbol and the logical page ID code symbol will be described, which are created in the page ID creation process D1, the page ID encoding process D2, and the two-dimensional modification process D5 shown in
(a) in
In the page ID encoding process D2, a parity is added to eight bytes of the address value. (b) in
In the two-dimensional modification process D5, the logical page ID code added with the parity is converted into a logical page ID code symbol. (c) in
The value of each of bytes LID[0], . . . , LID[7] and LIDP[0], . . . , LIDP[3] is each converted into two-dimensional patterns in accordance with the value in 4×4 pixels of 16 pixels, and arranged in the portion of the logical page ID as an area of 12 pixels in row and 16 pixels in column. In addition, as shown in the drawing, the area for four symbols at the right end, the area of four pixels in row and 16 pixels in column, is a black guard part in which all the pixels are at the black level. The black guard part is an area which secures the symbol space to a crosstalk detect symbol adjacent thereto as shown in
More specifically, even though pages are logically identical pages, the pages copied by the page duplication process C3 are added with physical page IDs separately.
(a) in
In the page ID encoding process D2, a parity is added to eight bytes of the address value. (b) in
In the two-dimensional modification process D5, the physical page ID code added with the parity is converted into a physical page ID code symbol. (c) in
The value of each of bytes PID[], . . . , PID[7] and PIDP[0], . . . , PIDP[3] is each converted into two-dimensional patterns in accordance with the value in 4×4 pixels of 16 pixels, and arranged in the portion of the physical page ID as an area of 16 pixels in row and 12 pixels in column. In addition, as shown in the drawing, the area for four symbols at the lower end, the area of 16 pixels in row and four pixels in column, is a black guard part in which all the pixels are at the black level. The black guard part is an area which secures the symbol space to a crosstalk detect symbol adjacent thereto as shown in
Next, the crosstalk detect symbol will be described, which is created in the crosstalk detect symbol creation process D4 shown in
First, for arrangement methods of the element holograms, two types of patterns can be considered: a square pattern in
In addition, as apparent from
The area of 18 pixels in row×18 pixels in column described above has nine areas in total, three areas in row × three areas in column, as one area has 6 pixels×6 pixels.
The crosstalk detect symbol shown in
A crosstalk detect symbol number is allocated to a single element hologram as shown in
For example, a crosstalk detect symbol having a crosstalk detect symbol number “0” (Symbol[0]) has a pattern of 18 pixels in row×18 pixels in column in which only four pixels shown in “0” in
In addition, a crosstalk detect symbol having a crosstalk detect symbol number “1” (Symbol[1]) has a pattern of 18 pixels in row×18 pixels in column in which only four pixels shown in “1” in
In addition,
As described above, in the crosstalk detect symbol creation process D4, the crosstalk detect symbols are created as a two-dimensional pattern having three areas in column x three areas in row (one area=6×6 pixels), nine areas in total. Particularly, such a two-dimensional pattern is formed that one area is the area including pixels at the white level, and the other areas are the areas including pixels at the black level among nine areas.
Then, by establishing the area including the pixels at the white level among nine areas, nine types of the crosstalk detect symbols, crosstalk detect symbol numbers “0” to “8”, are established.
In the crosstalk detect symbol creation process D4, the crosstalk detect symbols of individual numbers are outputted in a predetermined order so as to include the crosstalk detect symbols having the numbers allocated among a plurality of types of the crosstalk detect symbols (the crosstalk detect symbol numbers “0” to “8”) depending on the positions of the element holograms among the individual element holograms arranged in the element hologram matrixing process D7.
In addition, the crosstalk detect symbols of individual numbers are outputted in a predetermined order in such a way that different types of crosstalk detect symbols are given to the adjacent element holograms.
The method of using the crosstalk detect symbols will be described as examples are taken.
This is exemplary tracking that the element hologram of a crosstalk detect symbol number 4 is centered.
When reconstruction is made at a tracking position A shown in (j) in
When reconstruction is made at a tracking position B shown in (j) in
When reconstruction is made at a tracking position C shown in (j) in
When reconstruction is made at a tracking position D shown in (j) in
When reconstruction is made at a tracking position E shown in (j) in
Similarly, when reconstruction is made at a tracking position F shown in (j) in
When reconstruction is made at a tracking position G shown in (j) in
When reconstruction is made at a tracking position H shown in (j) in
When reconstruction is made at a tracking position I shown in (j) in
As described above, the relation between the element hologram matrix and the tracking positions is reflected in the reconstructed image of the crosstalk detect symbols.
When reconstruction is made at a tracking position A shown in (j) in
When reconstruction is made at a tracking position B shown in (j) in
When reconstruction is made at a tracking position C shown in (j) in
When reconstruction is made at a tracking position D shown in (j) in
When reconstruction is made at a tracking position E shown in (j) in
Similarly, when reconstruction is made at a tracking position F shown in (j) in
When reconstruction is made at a tracking position G shown in (j) in
When reconstruction is made at a tracking position H shown in (j) in
When reconstruction is made at a tracking position I shown in (j) in
As described above, the relation between the element hologram matrix and the tracking positions is reflected in the reconstructed image of the crosstalk detect symbols.
Similarly in
For the typical example of tracking, two cases are considered: the case in which reconstruction is made for right above an element hologram (just tracking), and the case in which reconstruction is made for the middle positions between a plurality of element holograms (half tracking). As shown in
Although specific explanations at the tracking positions are omitted, for similar understanding as in the cases in
In addition, in reality, there is also a delicate intermediate condition between the just tracking condition and the half tracking conditions. In this case, the condition appears as the balance in the intensity of the white level portions in the crosstalk detect symbol.
Next, the reconstructed images of the crosstalk detect symbols will be described when the element holograms are arranged in the staggered pattern as shown in
In (j) in
When reconstruction is made at a tracking position A shown in (j) in
When reconstruction is made at a tracking position B shown in (j) in
When reconstruction is made at a tracking position C shown in (j) in
When reconstruction is made at a tracking position D shown in (j) in
When reconstruction is made at a tracking position E shown in (j) in
Similarly, when reconstruction is made at a tracking position F shown in (j) in
When reconstruction is made at a tracking position G shown in (j) in
When reconstruction is made at a tracking position H shown in (j) in
When reconstruction is made at a tracking position I shown in (j) in
As described above, the relation between the element hologram matrix and the tracking positions is reflected in the reconstructed image of the crosstalk detect symbols.
When reconstruction is made at a tracking position A shown in (j) in
When reconstruction is made at a tracking position B shown in (j) in
When reconstruction is made at a tracking position C shown in (j) in
When reconstruction is made at a tracking position D shown in (j) in
When reconstruction is made at a tracking position E shown in (j) in
Similarly, when reconstruction is made at a tracking position F shown in (j) in
When reconstruction is made at a tracking position G shown in (j) in
When reconstruction is made at a tracking position H shown in (j) in
When reconstruction is made at a tracking position I shown in (j) in
As described above, the relation between the element hologram matrix and the tracking positions is reflected in the reconstructed image of the crosstalk detect symbols.
In addition,
For similar understanding as in the cases in
Also in this case, in reality, there is also a delicate intermediate condition between the just tracking condition and the half tracking conditions. In this case, the condition appears as the balance in the intensity of the white level portions in the crosstalk detect symbol.
The crosstalk detect symbols can be used for determining tracking conditions in reconstruction as described above.
Then, as described in
In addition, the page search symbol is combined with the group sub-sync to form a group main-sync. Then, a plurality of groups main-sync is combined to form a physical page, and a single element hologram is formed based on the physical page.
The element holograms are arranged in a two-dimensional matrix to form a hologram unit matrix 20.
7. Advantages of Embodiment
In the embodiment, the following advantages can be obtained.
In the embodiment, a data page is created from input data as a linear information sequence to be an encoding target, and inner encoding and outer encoding are conducted for the data page. After that, a physical page as two-dimensional data is created, and the physical page is formed into an element hologram matrix, whereby an encoding scheme can be implemented which is preferable for information recording on a hologram recording medium.
Particularly, in the sector splitting process A2 and the EDC adding process A3 in the scrambled page data generator 11, data to be element holograms is split into sectors and added with EDC, whereby the reliability of finally corrected data can be determined in units of sectors.
In addition, in the scramble process A4 in the scrambled page data generator 11, the logical page is scrambled to form a state in which the recorded data cannot be easily estimated from the physical page optically read. Thus, the embodiment is preferable in view of the security and copyright protection of contents data and computer data recorded on the hologram memory 3.
In addition, in the data array transform process B1 and the inner page encoding process B2 in the inner page encoder 12, an error correcting code is added to the logical page unit, whereby error detection and correction is allowed in units of logical pages.
In addition, in the inner page interleave process B3, the interleave process is conducted which is completed inside the logical page, whereby symbol errors caused by the intensity fluctuations and geometric shifts in the physical page can be distributed throughout the physical page.
In addition, the interpage encoding process C2 is conducted in the outer page encoder 13 to eliminate the necessity to read all the pages in the reconstruction of the hologram unit matrix 20 (in the reconstruction of the hologram memory 3 on which the hologram unit matrix 20 is formed). For example, in the case in which 16 pages of parity pages are added to 112 pages of logical page pages, when 77.5% of all the logical pages is finished to read, loss correction is conducted for the unread pages, whereby the full reconstruction of all the logical pages is allowed. Therefore, the implementation of efficient scan and improved data read performance in reconstruction can be intended.
In addition, the page duplication process C3 is conducted in the outer page encoder 13 to allow a closed stack element hologram matrix, and thus the read operation of element holograms can be facilitated.
In addition, the page ID creation process D1 conducted in the hologram unit matrix generator 14 adds the logical page ID uniquely allocated to the inner encoded page and the physical page ID uniquely allocated to the outer encoded page. Thus, in the reconstruction of the physical page from the element holograms, the physical reconstruction position can be first grasped by the physical page ID, and the logical reconstruction position can be grasped at which the physical page is developed as the logical page on the RAM on the reconstruction apparatus side.
In addition, in the two-dimensional modification process D6, as shown in
Moreover, four groups of the group R configure a group sub-sync. The sub-sync pattern is established at the center, and the main sync symbol is configured of 4×4 symbols. Thus, as apparent from
In addition, 30 patterns shown in
In addition, the page search symbol has the size that is an integral multiple of the group sub-sync. The group sub-sync has 16×16 pixels, and the page search symbol has 32×32 pixels. In other words, the page search symbol has the size of four groups sub-sync. With this configuration, even though the page search symbol is placed at a given symbol position on the group main-sync, the positions of center of gravity of the main sync symbol and the sub-sync pattern can maintain regularity both on the vertical axis and on the horizontal axis.
In addition, as described in
In addition, as described in
Particularly, the adjacent element holograms are allocated with different crosstalk detect symbol numbers all the time, that is, the adjacent element holograms are established to be different crosstalk detect symbols all the time, whereby the tracking condition in physical page reconstruction can be detected by fluctuations in intensity of the crosstalk detect symbols.
As described above, the embodiment is described. However, the process procedures and patterns described in the embodiment are merely an example. For an embodiment of the invention, various modifications can be considered within the scope of the teachings.
It should be understood by those skilled in the art that various modifications combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2005-249082 | Aug 2005 | JP | national |
