KR20030081600A - Holographic digital data storage/reproducing system and addressing method thereof - Google Patents

Abstract

PURPOSE: A system for recording and reproducing holographic digital data and a method of addressing the system are provided to generate an addressing code capable of minimizing code rate and record the addressing code in each page. CONSTITUTION: A system for recording and reproducing holographic digital data includes a code generator(121), a code recording part(122), an output part(110), a grouping part(123), and a page reading part(124). The code generator generates a plurality of addressing codes. The code recording part sequentially records addressing codes arranged in a row in the addressing region of each page. The output part outputs the addressing codes by bits in the case of reproduction mode. The grouping part groups m+1 addressing codes from the addressing codes of a reproducing page using the output addressing codes. The page reading part searches the m+1 addressing codes for the first and second reference bits, reads the starting point of the reproducing page using a difference between the positions of the first and second reference bits, and counts from the starting point to the addressing code of the reproducing page to read information of the reproducing page.

Description

Holographic digital data storage and playback system and addressing method {HOLOGRAPHIC DIGITAL DATA STORAGE / REPRODUCING SYSTEM AND ADDRESSING METHOD THEREOF}

The present invention relates to a holographic digital data storage and reproducing system, and more particularly, to a holographic digital data storage and reproducing system for generating an addressing code capable of minimizing a code rate and recording the same in each page.

Currently, holographic digital data storage (Holographic Digital Data Storage) applying semiconductor laser, charge coupled device (CCD), liquid crystal display (LCD), etc. is being actively researched and developed. Holographic digital data storage devices have the advantages of large storage capacity and ultra-fast data transfer speed, so they are not only being used as fingerprint recognition devices and display devices for storing and reproducing fingerprints, but also their application fields are gradually expanding. .

The holographic digital data storage and reproducing apparatus interferes with the object light transmitted from the target object and the reference light, and then reacts the interference fringe generated by the interference according to the amplitude and phase of the interference fringe differently. It records in a storage medium such as a photorefractive crystal to store the three-dimensional hologram data. It blocks the object light and provides only the reference light to the storage medium to reproduce the stored three-dimensional hologram data.

1 is a block diagram showing a holographic digital storage and playback system according to the prior art.

Referring to FIG. 1, a conventional holographic digital storage and system includes a light source 10, a light separator 11, a spatial light modulator (SLM) 11, a first lens 13, and a rotating mirror 14. ), An actuator 15, a reflector 16, a second lens 17, a storage medium 18, a third lens 19, a CCD 20, and a central control unit 30. The optical splitter 11 splits the laser beam of the light source 10 into two, so that the two paths including the plurality of optical systems, that is, the reference light path S ₁ and the object, are separated between the optical splitter 11 and the storage medium 18. An optical path S ₂ is formed.

First, the light separator 11 separates the laser light incident from the light source 10 into the reference light and the light of the object, wherein the reference light of the vertically polarized light is provided in the reference light path S ₂ , and the separated object light Is provided by the object light path S ₁ .

The reference light separated from the optical separator 11 and vertically polarized to the rotating mirror 14 is adjusted through an optical lens (not shown) and extended to an arbitrary size (extended to a sufficient size to cover the size of the object light). The light is incident on the storage medium 18 after being deflected through a reflector 16 at a predetermined angle, for example, a recording or reproducing angle.

On the other hand, the object light which is separated from the light separator 11 and is incident through the opening of the shutter (not shown) is transmitted to the spatial light modulator 12. The shutter keeps open when data is recorded, and keeps cut off when data is reproduced. The spatial light modulator 12 modulates the object light in units of pages of binary data of light and dark, which form pixels, according to external input data. The object light modulated in this manner is incident on the storage medium 18 in synchronization with the reference light.

In the storage medium 18, an interference fringe obtained through the interference between the modulated object light provided from the spatial light modulator 12 and the corresponding reference light is recorded. That is, the light induced phenomenon of the kinetic charge occurs in the storage medium 18 according to the intensity of the interference fringe caused by the interference between the modulated object light and the reference light. An interference fringe of the hologram data is recorded. The holographic digital storage system may move the storage medium 18 to record data or rotate the rotating mirror 14 to record data by using the actuator 15 controlled by the central controller 30.

At this time, the data stored in the storage medium 18 includes an addressing code. The method of recording the addressing code includes a method of recording an addressing code in a test page by inserting one test page for each preset page; There is a method of inserting addressing code by applying a binary differential method to data of each page.

This addressing code is recorded by the vertically polarized reference light in the optical splitter 11. The addressing code recorded in this way can be used to obtain information about the page being played back. You can go directly to the page and play it.

However, the method of recording the addressing code by inserting test pages at preset page intervals sets the test pages at preset intervals, thereby reducing the number of pages that can be recorded by the number of test pages inserted in the storage medium 18. There is a problem of lowering the recording density of the storage body 18.

The method of inserting an addressing code by applying a binary differential method has a problem in that a code rate decreases because data and an addressing code are recorded together so that data that can be recorded on a page is limited.

For example, when the number of pages to be distinguished is 2 ⁿ , since 2n bits of addressing code are required, the data that can be written on one page is reduced.

On the contrary, during reproduction, the object light separated from the optical separator 12 is blocked by the shutter 14, and the reference light for reproduction is stored through the rotating mirror 14, the reflector 16, and the second lens 17. In the case of the incident signal, the storage medium 18 diffracts the reproduction reference light into which the recorded interference fringe is incident, reproduces the recorded signal, and sends it to the CCD 20. The CCD 20 restores the reproduction signal sent from the storage medium 22 to an electrical signal, outputs three-dimensional hologram data, and transmits an addressing code to the central control unit 30.

The central control unit 30 obtains the page information reproduced by using the addressing code output from the CCD 20. The addressing code is recorded by inserting one test page for each preset page and recording the addressing code on the test page. When the test page is read, it is possible to obtain information on which pages are currently being reproduced, but not accurate page information.

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem of the prior art, and generates an address code of m × m format including the first and second reference bits according to the reference page m, and records it on each page. To provide a holographic digital data storage and reproducing system and an addressing method for grouping m + 1 codes in an addressing code of a page being played and reading page information using the grouped first and second reference bit positions. do.

In order to achieve the above object, the present invention provides a holographic digital data storage and reproducing system for recording holographic digital data and addressing codes on a page basis in a storage medium using reference light and object light separated from a light source. When the reference page is m, code is generated in the form of m × m, wherein each circle of the m × m matrix is composed of 2 bits, and is arranged in a circle and a row arranged in a diagonal direction based on the first row and the first column. The circle to which the reference code belongs is a reference code, and the first reference bit of the diagonal reference code and the second reference bit in the one-row direction are defined as the same value, and bits other than the first and second reference bits defined above are defined as A code generation unit for generating a plurality of addressing codes having values different from 1 and 2 reference bits, and addressing codes arranged in a column direction starting from the first row and the first column; A code recording unit for recording in the addressing area of each page, an output unit for outputting the addressing code bit by bit in the reproduction mode, and the addressing code of the page being reproduced using the addressing code output in the bit unit m + A grouping unit for grouping one addressing code, and searching for the first and second reference bits among the m + 1 addressing codes and using the difference between the positions of the second reference bit and the first reference bit. And a page reading section for reading the starting position point of the cell, counting from the starting position point to the addressing code of the playing page at the second reference bit, and reading the page information being played.

The present invention provides a method of addressing a holographic digital data storage and reproduction system in which holographic digital data and an addressing code are recorded in a page unit on a storage medium by using reference light and object light separated from a light source. When the code is generated in m × m format, each circle of the m × m matrix is composed of 2 bits, and the circles arranged in the diagonal direction with respect to the first row and the first column and the circle belonging to the first row are the reference codes. The first reference bit of the diagonal reference code and the second reference bit in the one-row direction are defined as the same value, and bits other than the defined first and second reference bits are defined as the first and second reference bits. Generate a plurality of addressing codes having a different value from each other, and sequentially address the addressing codes arranged in a column direction starting from the first row and the first column. Recording in an addressing area of the memory; grouping m + 1 addressing codes from addressing codes of a page being reproduced using the addressing codes output in units of bits; Retrieving a start position point of the playback page using the step of searching for the first and second reference bits, and using the difference between the positions of the second reference bit and the first reference bit, and starting from the start position point at the second reference bit. Counting up to an addressing code of the reproduction page to read the reproduction page information.

1 is a block diagram illustrating a holographic digital data storage and playback system according to the prior art;

2 is a block diagram illustrating a holographic digital data storage and system in accordance with the present invention;

3 is a diagram illustrating an addressing area in each page according to the present invention;

4 is a diagram illustrating an addressing code generated by a holographic digital data storage and reproducing system according to the present invention.

FIG. 5 is an exemplary diagram showing addressing codes grouped for extracting page information during reproduction in a holographic digital data storage and reproducing system according to the present invention.

<Description of the code | symbol about the principal part of drawing>

100: light source 101: optical separator

102: spatial light modulator 103: first lens group

104: rotating mirror 105: actuator

106: reflector 107: second lens group

108: storage medium 109: third lens group

110: output unit 120: central control unit

There may be a plurality of embodiments of the present invention, and a preferred embodiment will be described in detail below with reference to the accompanying drawings. Those skilled in the art will be able to better understand the objects, features and advantages of the present invention through this embodiment.

2 is a block diagram illustrating a holographic digital data storage and system according to the present invention, FIG. 3 is a diagram illustrating an addressing area in each page according to the present invention, and FIG. 4 is a holographic digital data storage according to the present invention. And an addressing code generated by the system.

Referring to FIG. 2, the holographic digital data storage and reproduction system includes a light source 100, a light separator 101, a spatial light modulator (SLM) 102, a first lens group 103, and a rotating mirror. 104, an actuator 105, a reflector 106, a second lens group 107, a storage medium 108, a third lens group 109, an output unit 110, and a central control unit 120. . Since the optical separator 101 separates the laser light of the light source 100 into two, two paths including a plurality of optical systems, that is, the reference light path S ₁ and an object, are separated between the optical separator 101 and the storage medium 108. An optical path S ₂ is formed.

First, the optical separator 101 separates the laser light incident from the light source 100 into the light of the reference light and the object, wherein the reference light of the vertically polarized light is provided to the reference light path S ₂ and the separated object light. Is provided by the object light path S ₁ .

The reference light separated from the optical separator 101 and vertically polarized to the rotating mirror 104 is adjusted through an optical lens (not shown) and extended to an arbitrary size (extended to a sufficient size to cover the size of the object light). It is deflected through a reflector 106 at a predetermined angle, for example, a recording or reproducing angle, and then enters the storage medium 108.

Meanwhile, object light that is separated from the light separator 101 and incident through the opening of the shutter (not shown) is transmitted to the spatial light modulator 102. The shutter keeps open when data is recorded, and keeps cut off when data is reproduced. The spatial light modulator 102 modulates the object light in units of pages of binary data of light and dark, which form pixels, according to external input data. The object light modulated as described above is incident to the storage medium 108 in synchronization with the reference light.

In the storage medium 108, an interference fringe obtained through the interference between the modulated object light provided from the spatial light modulator 102 and the corresponding reference light at the time of recording is recorded. That is, the light induced phenomenon of the kinetic charge occurs in the storage medium 108 according to the intensity of the interference fringe caused by the interference between the modulated object light and the reference light, and through this process, the hologram data is stored in the storage medium 108. Interference fringes are recorded. The holographic digital storage system then records the addressing code in a predetermined area of each page when data is recorded on the storage medium 108.

As shown in FIG. 3, the page stored in the storage medium 108 is divided into a data area 200 in which data to be reproduced is recorded, and an addressing area 210 in which an addressing code is recorded, and the addressing area 210. The current page information being reproduced can be known based on the addressing code recorded in &quot;

The central control unit 120 generates the addressing code (code including the first and second reference bits) to be recorded in the addressing area 210 in the form of m × m (m is a reference page, m ² pieces). ), The code recording unit 122 for recording the generated addressing code in the addressing area using an ankle multiplexing or a shift multiplexing method, and in response to any page request signal stored in the storage medium, A grouping unit 123 for grouping into one, searching for the first and second reference bits in the addressing codes grouped into m + 1, and calculating the difference between the position of the second reference bit and the first reference bit to start the playback page. A page reader 124 for reading the position point, counting from the position point to the addressing code of the playback page from the second reference bit to obtain the page information being played, using the page information And a page shifter 125 for calculating the deflection angle of the reproduction reference light of the reproduction request page, and outputting the reproduction request page by deflecting the reproduction reference light by the deflection angle.

The addressing code recorded in the addressing area 210 is generated by the code generating unit 121. The addressing code is generated in the form of m × m when the reference page is m, as shown in FIG. Each circle of the m matrix is composed of 2 bits, the circle arranged in the diagonal direction with respect to the first row and the first column, and the circle belonging to the first row is the reference code, and the first reference bit and the first row of the diagonal reference code. The second reference bit in the direction is defined as the same value, and bits other than the defined first and second reference bits have different values from those of the defined first and second reference bits.

At this time, the reference page m can be arbitrarily determined, has a value larger than 1, and the first and second reference bits are used to detect the corresponding page information during data reproduction.

For example, when the reference page is 10, the total number of addressing codes to be recorded on each page generated by the code generating unit 121 is 10 ^2, and the form of the addressing code is shown in Table 1 below.

1,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,0 1,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 1,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 1,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 1,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 1,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 1,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 1,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 1,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 1,0

Among the addressing codes generated by the code generation unit 121, the circles (1,1) in one row and one column are recorded in the addressing area 210 of the first page, and the circles (0,0) in the first row and second column are recorded in the second page. In the addressing area 210, the first and second reference bits are set to 1 (i.e., "on" bits) in each addressing code, and the value of the reference bit can be arbitrarily adjusted.

The code recording unit 122 of the central control unit 120 records the addressing code generated by the code generation unit 121 in the addressing area 210 of each page by the reference light separated by the optical separator 101 in the same manner as described above. In this case, the method of recording the addressing code in the addressing area 210 is controlled by the actuator 105 which rotates the rotating mirror 104 to move up and down the angle multiplexing and storage medium 108 which records the addressing code in the addressing area. There is shift multiplexing to move and record the addressing code. The addressing code is also recorded in the addressing area 210 which is the upper left of each page for recording data.

When the object light separated from the optical separator 101 is blocked through the shutter and the reproduction reference light enters the storage medium 108 through the rotating mirror 104 and the reflector 106, the recorded interference in the storage medium 108 is recorded. The reproduced reference light is diffracted by the pattern incident, and the recorded signal is reproduced and sent to the output unit 110 through the third lens group 109. The output unit 110 outputs the hologram data by reconstructing the reproduction signal sent from the storage medium 108 into an electrical signal and processing the signal in bits (pixels), wherein the output data is processed in bits instead of pages. CMOS is used to do this.

The third lens group 109 adjusts the interference fringe reconstructed by the storage medium 108 to match the number of bits (pixels) and transmits the adjusted fringe to the output unit 110.

Before outputting data, the output unit 110 processes the addressing code recorded in each page in units of bits and transmits it to the central controller 120.

The grouping unit 123 extracts and groups m + 1 addressing codes on the basis of the addressing code currently being reproduced in response to any page reproduction request signal stored in the storage medium 108.

The page reader 124 retrieves the first and second reference bits from the grouping addressing codes, and the page currently being reproduced by using the position difference from the second reference bit to the first reference bit is the starting position point (a). The information of the current playback page can be obtained by counting and calculating the count number b by counting from the second reference bit to the addressing code of the currently playing page. The page information is shown in Equation 1 below.

Page information = a × m + b

The page shifter 124 calculates the deflection angle of the reproduction reference light for reproduction of the reproduction request page using the page information read by the page reader 124, and deflects and stores the reproduction reference light at the calculated deflection angle. Enter the medium 108.

The storage medium 108 outputs the reproduction request page to the outside through the third lens group 109 and the output unit 110 according to the incident reproduction reference light.

A process of reading information of a page currently being reproduced by using an addressing code recorded in a predetermined area among a page area composed of a plurality of pixels using the holographic digital storage and reproducing system having the above configuration will be described below. .

First, the code generator 121 generates 100 addressing codes using a reference page of 10, and the code recorder 122 stores the addressing codes generated by the code generator 121 in a preset manner. It will be described under the assumption that the data is sequentially recorded in a predetermined area of the page to be recorded.

In addition, since the addressing code is composed of 2 bits, it is assumed that the first bit is A, and the second bit is B.

In the reproduction mode, the output unit 110 processes the addressing code recorded in each page in bit units and transmits the signal to the central control unit 120, and the grouping unit 123 of the central control unit 120 requests an arbitrary page reproduction. Based on the addressing code of the page currently being reproduced in response to the signal, as shown in FIG. 5, eleven addressing codes are extracted and grouped.

The page reader 124 searches the positions of the second reference bit and the first reference bit among the grouping addressing codes, counts the difference between the positions of the second reference bit and the first reference bit, and starts the page being played. The location point is known. That is, it can be seen that the difference from the second reference bit to the first reference bit is -4, which indicates that the difference between the first and second reference bits is 6, and this information indicates that pages before the starting position point are 61-70 pages. Indicates. Therefore, the starting position point obtained by the input addressing code is 60 pages.

The page reading unit 124 counts from the second reference bit to the first of the present playing code based on the start position point and reads that the currently playing page is 76 pages.

The page shifter 125 calculates the deflection angle of the reproduction reference light according to the difference 6 between the page currently being reproduced and the reproduction request page when the reproduction request page is 70 pages, and the rotating mirror 104 at the calculated deflection angle. Actuator 105 generates a control signal, and the actuator 105 rotates the rotating mirror 104 by the deflection angle to inject the reference light for reproduction into the storage medium 108.

The storage medium 108 outputs a reproduction request page (page 70) through the third lens group 109 and the output unit 110 in response to the reproduction reference light.

As described above, when the reference page is m, a plurality of addressing codes are generated in an m × m format in which each circle is 2 bits, recorded in the addressing area in each page, and m + from the addressing code of the page being played in the reproduction mode. Grouping one addressing code, searching for the first and second reference bits among the m + 1 addressing codes, reading the starting position point of the playback page using the difference between the positions of the second reference bit and the first reference bit By counting from the start position point to the addressing code of the playback page from the second reference bit and reading the page information being played, each page can be addressed with an addressing code consisting of 2 bits, thereby improving the code rate.

Claims (8)

A holographic digital data storage and reproduction system for recording holographic digital data and addressing codes on a page basis in a storage medium using reference light and object light separated from a light source. When the reference page is m, a code is generated in the form of m × m, wherein each circle of the m × m matrix is composed of 2 bits, and belongs to a circle arranged in a diagonal direction with respect to the first row and the first column. The circle is a reference code, and the first reference bit of the diagonal reference code and the second reference bit in the one-row direction are defined as the same value, and bits other than the first and second reference bits defined above are the first defined bits. A code generator for generating a plurality of addressing codes having values different from 2 reference bits; A code recording unit for sequentially writing addressing codes arranged in a column direction starting from the first row and the first column, to an addressing area of each page; An output unit for outputting the addressing code in units of bits in a reproduction mode; A grouping unit for grouping m + 1 addressing codes from addressing codes of a page being reproduced by using the addressing codes output in units of bits; The first and second reference bits are searched among the m + 1 addressing codes, the starting position point of the reproduction page is read using the difference between the positions of the second reference bit and the first reference bit, and the starting position is read. And a page reader which counts from a point to the addressing code of the reproduced page from the second reference bit to read the reproduced page information. The method of claim 1, And a page shifter configured to calculate a deflection angle of the reference light for reproduction using the difference between the page information being reproduced and the reproduction request page, and output the reproduction request page using the deflection angle. Digital data storage and playback system. The method of claim 1, The addressing code is, Holographic digital data storage and reproducing system characterized in that it is recorded together in a predetermined area of the page. The method of claim 1, The output unit, Holographic digital data storage and reproducing system, characterized in that the CMOS for signal-processing the data output in units of pages. An addressing method in a holographic digital data storage and reproduction system for recording holographic digital data and an addressing code on a page basis in a storage medium using reference light and object light separated from a light source. When the reference page is m, a code is generated in the form of m × m, wherein each circle of the m × m matrix is composed of 2 bits, and belongs to a circle arranged in a diagonal direction with respect to the first row and the first column. The circle is a reference code, and the first reference bit of the diagonal reference code and the second reference bit in the one-row direction are defined as the same value, and bits other than the first and second reference bits defined above are the first defined bits. Generating a plurality of addressing codes having a value different from 2 reference bits, and sequentially writing the addressing codes arranged in a column direction starting from the first row and the first column to an addressing area of each page; , Grouping m + 1 addressing codes from the addressing codes of the page being reproduced by using the addressing codes output in units of bits; Retrieving the first and second reference bits from the m + 1 addressing codes; The start position point of the playback page is read using the difference between the position of the second reference bit and the first reference bit, and the play point is counted from the start position point to the addressing code of the play page from the second reference bit. And reading the page information being read. The method of claim 5, And calculating a deflection angle of the reference light for reproduction using the difference between the page information being reproduced and the reproduction request page, and outputting the reproduction request page using the deflection angle. Addressing method of data storage and playback system. The method of claim 6, The outputting of the reproduction request page may include: And changing the position of the storage medium according to the deflection angle to move to the reproduction request page. The method of claim 5, The addressing code is, A method of addressing a holographic digital data storage and reproducing system, characterized in that recorded in a predetermined area of the page.