KR20030082667A - Holographic digital data storage/reproducing system and addressing method thereof - Google Patents

Abstract

PURPOSE: A system for storing and reproducing holographic digital data, and A method for addressing thereof are provided to generate a plurality of address codes by using a fewer bits, thereby improving a code rate. CONSTITUTION: A bit setting unit(121) calculates the total number of pages to be stored in a storage medium for deciding the number of bits necessary for addressing codes. A code generating unit(122) divides the bits into one reference bit, m bit page dividing group, and n reference groups formed of m bits, wherein two bits of the m bits are selectively "on" and the reference bit value becomes "on" to generate the addressing codes. A code recording unit(123) records the "on" bits and data by having a predetermined difference in an incident angle of a reference beam. An output unit(110) outputs data output from the storage medium by pixels, and transmits the addressing code related to the output data. A group reading unit(124) judges the number of the reference groups by dividing the bit number except the last m bit and the reference bit by m, and compares values of bit values of the reference groups for reading the group to which the reproduced page belongs. A page reading unit(125) reads information of the page which is being reproduced, by using the bits having the minimum difference.

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 and an addressing method for generating an addressing code that can minimize the code rate and improve the reproduction efficiency and to record each page. It is about.

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 rate, so they are not only being used as fingerprint recognition devices and display devices for storing and reproducing fingerprints, but their applications are also 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 data 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) 12, 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 separator 11 separates the laser beam of the light source 10 into two, and between the optical separator 11 and the storage medium 18, two paths including a plurality of optical systems, that is, the reference light path S ₁ and The object light 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 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 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 made of crystal or polymer, an interference fringe obtained through interference between the modulated object light provided from the spatial light modulator 12 and the corresponding reference light is recorded in recording. 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 using the actuator 15 controlled by the central controller 30.

The holographic digital data storage and reproducing system records addressing codes in a predetermined area of each page before recording data in units of pages on the storage medium 18. A method of recording such addressing codes is described in US Pat. No. 5,777,760. have.

Referring to FIG. 2, the addressing code is recorded on the outer circumferential surface of the pattern (page) on which data is recorded, and the addressing code is recorded on the outer circumferential surface at five points on the X axis (A _X , B _X , C _X , D _X , E). _X ) and five points on the Y axis (Ay, By, Cy, Dy, Ey), each of which is recorded with an arbitrary value (“0” or “1”) by the reference light.

Five patterns (for example, AB, BC) are recorded by recording an arbitrary value to maximize the distance between the two points in order to show the information of five patterns (pages) at five points on the X axis or the Y axis indicating the addressing code. , CD, DE, EA).

Referring to FIGS. 3A to 3E, the addressing code input method may define the pattern AB by displaying a reference light at a predetermined angle and displaying only A and B on the X axis as “on” (“1”). The pattern BC can be defined by displaying only B and C on the X axis as "on", and the pattern CD can be defined by displaying only C and D on the X axis as "on", and only D and E on the X axis as "on". The pattern DE can be defined by displaying, and the pattern EA can be defined by displaying only E and A of the X-axis as "on".

When Bragg selectivity is θ, the position of input data is -2θ, -θ, 0, θ, 2θ on each page, and A _X , B _X , C _X , D _X , E _X are recorded with a difference of 0.5θ. At this time, A _X is recorded at-0.75θ, B _X is recorded at -0.25θ apart from 0.5θ, and C _X is also recorded at 0.25θ away from 0.5θ. In this way, _X D and _X E is and recorded in 0.75θ and 1.25θ, again as _X A is recorded in 1.75θ.

4 to 5 are graphs showing the reproduction efficiency of the data and the addressing data in the reproduction mode. When the holographic digital data storage and reproduction apparatus reproduces arbitrary data when the incident angle of the reproduction reference light is 0 °, the data image D1 is shown. Denotes the maximum, and B and C of the addressing data indicate the maximum value, thereby finding the data image D1.

In this manner, the holographic digital data storage and reproducing apparatus can find the data image D2 at a position where the values of the addressing data D and E have a maximum value, and can find the data image D3 using A and B. FIG.

FIG. 6 is a graph illustrating an intensity difference between two addressing data in the reproduction mode, and the central controller 30 may calculate a difference in intensity between the addressing data and retrieve a data image currently being reproduced.

That is, as shown in FIG. 6, the central control unit 30 knows that the data image D1 is being reproduced because the intensity difference between the addressing data B and C is 0 when the reproduction reference light is incident at θ. It can be seen that the data image D2 is being reproduced because the intensity difference between the addressing data D and E is 0 when the reference light is incident at 1 °.

However, there is a problem in that the code rate is lowered by using five pixels to record the addressing code that can distinguish five pages when writing the addressing data of the data image in the above manner.

In addition, since the addressing data A, B, C, D, and E do not all exhibit the same intensity according to the Gaussian distribution of the laser beam, which is a light source used in the holographic digital data storage and reproducing apparatus, a bit in which the addressing data is recorded. It is not possible to retrieve data image information currently being reproduced by using the density difference between them.

In the polymer used for the storage medium 18, since a shrinkage phenomenon occurs during data recording and Bragg mismatch occurs during data reproduction, the data cannot be reproduced at the point where the addressing data has the maximum density value of the recorded pixels. have.

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem of the prior art, and includes a page division group, a reference group, and a grouping of m bits having two bits having an "on" value according to the number of bits required according to the total number of pages of a storage medium. The present invention provides a holographic digital storage and reproducing system and an addressing method for recording an addressing code into an addressing area of each page using a reference bit and accurately retrieving page information being reproduced using the addressing code.

In order to achieve the above object, the present invention provides a holographic digital data storage and reproducing system for storing 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. A bit setting unit for calculating the total number of pages to be stored in the storage medium to determine the number of bits (l) required for the addressing code, and the l bits as one reference bit and m (m> 3) pages. It is divided into n reference groups composed of a division group and m bits, and two bits are selectively set to “on” among the m bits, and a value of the reference bit is set to “on” to generate an addressing code. A code generation unit and the incident angle of the reference light are set to be “on” in the addressing codes by a difference from a predetermined incident angle. A recording unit for recording the bits and the data, an output unit for outputting data output from the storage medium in pixel units, an output unit for transmitting an addressing code for the output data, and the number of bits of the address code output from the output unit The number of the reference group is determined by dividing the number of bits except the last m bit and the reference bit by m, comparing the values of the bits of the reference group, and reading the group to which the playback page belongs by using the bits whose difference is minimum. And a page reader for comparing the value of the m bits of the page division group and reading the page information being reproduced by using a bit whose difference is minimum.

The present invention relates to a method of addressing a holographic digital data storage and reproducing system for storing 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. Calculating the total number of pages to be stored and setting the number of bits (l) necessary for the addressing code; and the n bits comprising one reference bit, a page division group of m (m> 3) bits, and n bits. Generating an addressing code by dividing into two reference groups, wherein two bits are selectively set to “on” among the m bits, and a value of the reference bit is set to “on”; Recording the data and the bits that are turned “on” in the addressing codes by being different from a predetermined angle of incidence. Outputting the data output from the storage medium in units of pixels in the reproduction mode, and transmitting an addressing code for the output data, the last m bit and the reference bit among the number of bits of the output address code. Determining the number of reference groups by dividing the number of excluded bits by m, comparing the values among the bits constituting the reference group, reading a group to which a reproduction page belongs by using bits whose difference is minimum; Comparing the values of the m bits of the division group and reading out the page information being reproduced using the bits whose difference is minimum.

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

2 is a view showing a page form recorded on a storage medium by a holographic digital data storage system according to the prior art;

3A to 3E are diagrams showing recording forms of five addressing codes according to the prior art;

4 is a graph showing data reproduction efficiency according to the prior art;

5 is a graph showing the reproduction efficiency of the addressing code according to the prior art,

6 is a graph showing a difference in reproduction strength between two bits of an addressing code according to the prior art;

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

8 illustrates the form of a page recorded on a storage medium by the holographic digital data storage system according to the present invention;

9 illustrates the form of an addressing code used in a holographic digital data storage and reproduction 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.

FIG. 7 is a block diagram showing a holographic digital data storage and reproducing system according to the present invention, FIG. 8 is a view showing the form of a page recorded on a storage medium by the holographic digital data storage system according to the present invention. A diagram showing the form of an addressing code used in a holographic digital data storage and reproduction system according to the present invention.

Referring to FIG. 7, a holographic digital storage and 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. And 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 light separator 101 separates the laser light incident from the light source 100 into reference light and light of an object, wherein the reference light of vertical polarization 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 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 one page of light and dark binary data constituting 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 using crystal or polymer, an interference fringe obtained through interference between the modulated object light provided from the spatial light modulator 102 and the corresponding reference light is recorded in the recording. 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 moves the storage medium 108 to record the data.

As shown in FIG. 8, 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 addressing code recorded in the addressing area 210 selectively “on” or “off” the pixels representing the addressing code by a reference light having a predetermined angle of incidence before data is recorded or changes the position of the storage medium 108. To selectively "on" or "off" the pixels representing the addressing code.

The addressing code is stored in the addressing area 210 of each page by the reference light separated by the optical splitter 101. In this case, the method of recording the addressing code in the addressing area 210 may include an actuator for rotating the rotating mirror 104. Ankle multiplexing for controlling the addressing code 105 to record the addressing code in the addressing area and shift multiplexing for changing the phase of the storage medium 108 to record the addressing code. The addressing code is recorded in the addressing area 210 which is an upper left corner of each page as an example.

The central control unit 120 generates a control signal for adjusting the reflection angle of the reference light which is separated from the optical splitter 101 and vertically incident to record the addressing code in the addressing area 210 so that the reference light is transmitted to the addressing area 210. Incidentally, the corresponding addressing data is entered to be recorded, and the page information being reproduced is searched based on the addressing code output from the output unit 120. The configuration includes the bit setting unit 121, the code generating unit 122, and the code recording unit 123. ), A group reader 124, a page reader 125, and a page shifter 126.

The bit setting unit 121 sets the number of bits l for representing the addressing code according to the number of pages to be recorded in the storage medium 108, and the number of bits l set by the bit setting unit 121 is a code. The page divider group grouped by the generation unit 122 in units of m (m> 3) bits, n reference groups, and reference bits composed of one bit, wherein the page separator group is the last group among the plurality of groups, and the reference group Is the part except page division group.

The addressing code defined by the code generation unit 122 may include a reference group except for the page division group 220 / n, the reference bit 221, and the page division group 220 / n as shown in FIG. 220/1 to 220 / n-1), only two bits of the m bits constituting each group are “on” to represent an addressing code.

Since the code generation unit 122 generates codes by changing the positions of the pixels that are turned “on” among the m bits constituting each group, the number of addressing codes (pages) that can be expressed according to the number of bits is expressed by the following equation. Same as 1.

Number of pages = ( _m C ₂ ) ^{(l-1) / m}

In this case, m represents the number of bits in one group and l represents the total number of bits used in the addressing code.

For example, if the total number of pages of the input data to be recorded in the storage medium 108 is 6 ² pages, the bit setting unit 121 sets the total number of bits l to 9 bits and 4 bits are one group, It consists of two groups and has one reference bit.

The code recording unit 123 varies the incident angle of the reference light into a predetermined area of the page before the data is recorded on the storage medium 108 in accordance with the subject light, so that among the m bits corresponding to the addressing code generated by the code generating unit 122 Write the two bits to "on" (or "off").

Among the addressing codes generated by the code generating unit 122, the reference bit is recorded to be always “on” according to the incident angle of the reference light when the input data is recorded.

The input data is recorded in the storage medium 108 after the addressing code is recorded by the code recording unit 123, wherein the reference light when the input data is recorded in the storage medium 108 is determined by the reference light when the addressing code is input. The incident is made with a predetermined difference from the incident angle. The reference light incidence angle of the input data has a value out of -0.25θ and + 0.25θ respectively with each reference light incident angle at which two bits of “on” are recorded.

For example, suppose that the addressing code of six pages is recorded, the code recording unit 123 records the addressing code by using five bits.

The code recording unit 123 “on” A1 and B1 to express the addressing code of the first page. When the incident angle of the reference light is -0.25θ, it records “1” in A1 and B1 when the incident angle of the reference light is 0.25θ. Record “1” in the box. At this time, the incident angle of the reference light when the input data is recorded in the storage medium 108 is "0".

In this manner, the central control unit 120 records “1” in A1 when the incident angle of the reference light is 0.75θ on the second page, and writes “1” in C1 when the incident angle of the reference light is 1.25θ, and the incident angle of the reference light. The input data is recorded.

In other words, the addressing codes of the respective pages recorded by the central control unit 120 are shown in Table 1 below.

Page Addressing code First page 11001 Second page 10101 Third page 10011 Fourth page 01101 Fifth page 01011 Sixth page 00111

Among the addressing codes, the page division group and the n reference groups are recorded before the input data is recorded, and the reference bits are always recorded to have an "on" value when the input data is written.

The central control unit 120 may reproduce the data in the portion having the best SNR (the portion having the maximum value) at the time of data reproduction described later using the reference bit value.

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 units of bits (pixels). In this case, CMOS is used for output of units of bits.

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

The output unit 110 processes the addressing code recorded in each page before outputting the data in bit units and transmits it to the group reading unit 124 of the central control unit 120.

The group reading unit 124 determines the number of reference groups by dividing the number of bits except the last m bit and the reference bit by m from the number of bits of the address code output from the output unit 110, and between the bits belonging to the reference group. The values are compared and the group to which the playback page belongs is read using the bits whose difference is minimum.

The page reading unit 125 compares the values between the m bits of the page division group and reads out the page information being reproduced by using the bits whose difference is minimum.

The page shifter 126 uses the page information read by the page reader 125 to refer to a user for moving from the page information to the playback request page according to any page playback request among the pages stored in the storage medium 108. Set the deflection angle of the light or move the position of the storage medium 108 to the playback request page, in which the rotating mirror 104 is rotated or the position of the storage medium 108 is changed to change the position of the page according to the deflection angle. Output through the output unit 110.

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

First, the holographic digital storage and reproducing system will store a total of 36 pages, one group is composed of four bits, and will be described on the assumption that two bits of four bits are turned on.

The bit setting unit 121 calculates the total number of bits required for each page when storing the data to be stored in units of pages. In this case, the total number of pages is 36 pages, so the number of bits necessary to express the addressing code is 9 bits.

The group classifier 122 divides the reference group grouped into 4 bits, the page division group, and the reference bits by using 9 bits set by the bit setting unit 121, and then uses 8 bits of the reference group and the page division group. Set 36 codes.

Among the addressing codes, the reference group consists of “1100, 1010, 1001, 0011, 0101, 0110”, and the page classification code group consists of “1100, 1010, 1001, 0011, 0101, 0110”. Record 1 always. The addressing code forms the addressing code through a combination of the reference group and the page separator code group.

The code recording unit 123 records the first reference group (“1100”) and the page classification code (“1100”) in the first page using the addressing code generated by the group classification unit 122. The addressing code of the second page records the reference group without change and only the page separator code is changed to “1010”. In this way, the page group code group is changed without changing the reference group and recorded from 1 to 6 pages. Then, using the second value (“1100”) of the reference group, record up to 7 to 12 pages and record the addressing code up to 36 pages.

The code recording unit 123 uses an addressing code using the reference light in the upper left addressing area 210 of the stored page of the storage medium 108 in which the input data is recorded in the binary data format of a plurality of pixels by the reference light and the object light. The addressing code is recorded by changing the position of the storage medium 108 or injecting the reference light into the addressing area 210. In this case, the code recording unit 123 records the addressing code before recording the input data in the storage medium 108. The incident angle of the reference light for recording the addressing code is recorded using a value different from the reference light incident angle when the input data is recorded. do.

When arbitrary data stored in the storage medium 108 is output, the output unit 110 outputs data in units of pages in units of bits (pixels). When a page having an addressing code of “10100101” is output, an output unit ( 110 transmits the addressing code to the group reading unit 124 of the central control unit 120.

The group reading unit 124 reads that the addressing code is composed of two groups by dividing the number of bits excluding the last reference bit by 4 bits from the total number of bits of the addressing code, wherein the first group is a reference group and the second group is Page separator group.

The group reading unit 124 reads that the page being reproduced is between 7 and 12 pages by using the reference group value "1010".

The page reader 124 may recognize that the page being reproduced is 11 pages using “0101” which is a page classification code group.

The page shifter 126 adjusts the deflection angle of the reference light for moving from the 11 pages currently being played back to the 25th page which is the playback request page according to the user's request to play any page (eg, page 25), or the storage medium. After moving to page 25 by adjusting the position of 108, the data of 25 pages stored in the storage medium 108 is output through the output unit 110 using the reference light.

As described above, the present invention calculates the total number of pages to be stored in the storage medium, and after determining the number of bits (l) required, the present invention includes one reference bit, m (m> 3) bits of page division group and n bits. Separate the reference group, but set the two bits among the m bits to be "on" selectively, and set the value of the reference bit to "on" to generate an addressing code to generate an incident angle of the reference light from the preset angle of incidence. After recording the bits and data that are turned “on” in the addressing codes, the number of reference groups divided by m, except for the last m bits and the reference bits, among the bits of the address code output from the storage medium in the playback mode. And compare the values of the m bits of the reference group with the values of the m bits of the page separation group and use the bits that minimize the difference. By reading the playing information page, it is possible to generate a plurality of addressable code by using a small number of bits it is possible to improve the code rate.

In addition, there is an effect that the data reproduction error caused by the Bragg mismatch due to the shrinkage phenomenon occurring when data is recorded on the storage medium can be prevented by using the reference bit value.

Claims (8)

A holographic digital data storage and reproduction system for storing holographic digital data and addressing codes on a page basis in a storage medium by using reference light and object light separated from a light source. A bit setting unit for calculating the total number of pages to be stored in the storage medium to determine the number of bits (l) required for the addressing code; The l bits are divided into one reference bit, a page division group of m (m> 3) bits, and n reference groups composed of m bits, and two bits of the m bits are selectively set to be “on”. A code generator for generating an addressing code by setting the value of the reference bit to be “on”; A recording unit for recording the data and the bits which are “on” in the addressing codes, having a predetermined difference in the incident angle of the reference light; An output unit configured to output data output from the storage medium in pixel units and to transmit an addressing code for the output data; The number of reference groups is determined by dividing the number of bits except the last m bit and the reference bit by m from the number of bits of the address code output from the output unit, and comparing the values of the bits of the reference group to minimize the difference. A group reading unit which reads a group to which a reproduction page belongs by using; And a page reader which compares the values of the m bits of the page division group and reads out the page information being reproduced by using the bits of which the difference is the smallest. The method of claim 1, The deflection angle of the reference light corresponding to the reproduction request page is set based on the read page information among the pages stored in the storage medium, or the position of the storage medium is shifted to change the reproduction request page. Holographic digital data storage and playback system further comprises a page moving unit for moving to. The method of claim 1, The number of addressing codes generated by the code generator is ( _m C ₂ ) ^{(n-1) / m} holographic digital data storage and playback system. The method of claim 1, Two bits that are "on" of the m bits, Holographic digital data storage and reproducing system, characterized in that recorded at an angle of incidence ± 0.25θ away from the reference light incident angle of the data. A method of addressing a holographic digital data storage and reproduction system for storing holographic digital data and an addressing code in a page unit on a storage medium by using a reference light and an object light separated from a light source, Calculating the total number of pages to be stored in the storage medium and setting the number of bits (l) necessary for the addressing code; The l bits are divided into one reference bit, a page division group of m (m> 3) bits, and n reference groups composed of m bits, and two bits of the m bits are selectively set to be “on”. Generating an addressing code by setting the value of the reference bit to be “on”; Recording the data and the bits which are “on” in the addressing codes by making the incident angle of the reference light different from a predetermined incident angle; Outputting data output from the storage medium in units of pixels in a reproduction mode, and transmitting an addressing code for the output data; The number of the reference group is determined by dividing the number of bits except the last m bit and the reference bit by m from the number of bits of the output address code, and comparing the values between the bits constituting the reference group to minimize the difference. Reading a group to which the playback page belongs by using; And comparing the values of the m bits of the page division group and reading out the page information being reproduced by using a bit having a minimum difference therebetween. The method of claim 5, The deflection angle of the reference light corresponding to the reproduction request page is set based on the read page information among the pages stored in the storage medium, or the position of the storage medium is shifted to change the reproduction request page. The method of claim 1 further comprising the step of moving to a holographic digital data storage and playback system. The method of claim 5, The number of addressing codes generated by the code generator is ( _m C ₂ ) ^{(n-1) / m The} method of addressing a holographic digital data storage and reproducing system. The method of claim 5, Two bits that are "on" of the m bits, And recording the data at an angle of incidence that is ± 0.25 [theta] apart from a reference light incident angle of the data.