KR101525383B1 - Device and method of recording and reconstructing information for enhancing BER in holographic data storage system - Google Patents

Abstract

According to an embodiment of the present invention, a method of recording information in a holographic data storage system and reproducing the recorded information comprises: an encoding step for binarizing a two-dimensional original image and converting the two-dimensional original image into a two-dimensional data page; a high frequency removal step for removing high frequency area information of the two-dimensional data page by using a Nyquist aperture; an image obtaining step for obtaining the two-dimensional data page with the high frequency area information removed by an image sensor; a digitizing step for applying a recursive image filter to the data page obtained from the image sensor; and a decoding step for reproducing the data page with the recursive image filter applied as two-dimensional original data.

Description

An apparatus and method for recording and reproducing information in a holographic data storage for improving a bit error rate (BER) of holographic data storage. {Device and method for recording and reconstructing information for enhancing BER in holographic data storage system}

The present invention relates to an apparatus and method for recording and reproducing information in a holographic data storage for improving a bit error rate (BER) of a holographic data storage, and more particularly, And to reduce the bit error rate (BER) inevitably generated in the reproduction process using a recursive image filter.

The page-based holographic data storage is a method of storing data in a two-dimensional binary data page format unlike a conventional optical storage device that stores information in units of bits, thereby realizing a dramatic increase in data capacity compared to the conventional one .

1 is a flowchart illustrating a process of recording and reproducing information in a holographic data storage. In order to record information in the holographic data storage, a modulation code is applied to the input data to encode it as a two-dimensional data page, and then recorded on a holographic disk through an optical system. When the recorded information is reproduced, it is obtained by an image sensor such as a CCD or CMOS through the reverse order of the recording system.

2 is a block diagram showing an optical system for recording and reproducing holographic data storage. Dimensional data to be recorded is displayed on a spatial light modulator (SLM) 10 and reflected on the phase of the signal beam. Thereafter, the signal beam is focused on the holographic disk 40 after passing through the primary Fourier lens 50, the physical Nyquist diaphragm 30 and the secondary Fourier lenses 61 and 62. The reference beam also passes through the lens to focus on the holographic disk 40. The holographic disk 40 records the hologram generated by interfering the focus information of the signal beam with the reference beam. At this time, if the incident angle of the reference beam is adjusted through the galvanometer mirror 20, it is possible to record a plurality of holograms at the same position.

At this time, the signal beam information of the focal plane includes a high-frequency region in addition to a low-frequency region seen in the eye, which is recorded together in the recording step and affects the data of the adjacent region, resulting in a decrease in recording density. To prevent this, Nyquist diaphragm is introduced to remove unnecessary high-frequency information before the introduced technique finally records optical information on the holographic disk. This makes it possible to record high density data compared to the conventional method. However, since a kind of information loss occurs while passing through the aperture, a bit error necessarily occurs in the process of reproducing the recorded information as compared with the original data. This bit error rate varies with the diameter of the aperture, thus limiting the aperture diameter and data recording density within an acceptable error range.

To overcome these drawbacks, two approaches have been proposed. First, methods such as modulation coding, channel coding, mechanical compensation, and sync mark, which were used to correct errors in conventional hard disk drives (HDDs) and optical disk drives (ODDs), have been applied. Second, the page-based holographic data storage is based on a two-dimensional imaging system, unlike the conventional hard disk (HDD) and optical disk driver (ODD) Has been proposed. In particular, an upscaling method has been proposed in which an acquired image is resized twice, and a point spread function (PSF) corresponding to the scale is obtained by a numerical method to restore a high resolution image. Both of the proposed methods are effective in reducing certain levels of error. However, since the former has borrowed the techniques used in the signal processing and mechanical control systems, the error reduction effect is not large. In the latter, it is necessary to secure high-level information about the optical system in advance and to perform additional processing in the up- There is a limitation in that the computation speed is reduced because the computation amount is required.

Embodiments of the present invention provide a recursive image filter used in a process of reproducing recorded data in order to improve a recording density of a holographic disk by reducing a bit error rate that necessarily occurs in a page based holographic data storage system. And a system using the same.

A method for recording and reproducing information in a holographic data storage according to the present invention includes: encoding an original image into a two-dimensional data page; A high frequency removing step of removing high frequency region information of the two-dimensional data page using a Nyquist aperture; An image acquiring step of acquiring the high frequency removed two-dimensional data page from the image sensor; A digitizing step of converting an image acquired by the image sensor into a data page of a binarization format; And a decoding step of reproducing the data page of the binarization format as two-dimensional original data.

In the encoding step, the two-dimensional original image is binarized by using a modulation code.

}을 1 내지 2의 값으로 설정하는 단계; (c) 각 영역에 대한 필터 값 {

}, (n은 반복횟수, n은 1 이상의 자연수)을 상기 데이터 페이지에 적용한 후, 데이터 페이지의 비트 에러 비율(BER)을 연산하는 단계; (d) 상기 필터 값에 일정 스텝 h 만큼 더해진 필터 값 {

}을 적용한 후 데이터 페이지의 비트 에러 비율(BER)을 연산하는 단계; 및 (e) 상기 (d)단계에서 연산한 비트 에러 비율(BER)에서 (c)단계에서 연산한 비트 에러 비율(BER)을 차감하여 그 값이 양수이면 (d)단계에서 연산한 비트 에러 비율(BER)을 최적화된 필터값으로 결정하고 그 값이 음수이면 다시 (c)단계로 다시 되돌아가는 단계;를 포함하며, 최적화된 필터값이 결정될 때까지 상기 (c) 내지 (e) 단계가 반복되고, 상기 결정된 필터값으로 설정되는 것을 특징으로 한다.In the digitizing step, the recursive image filter comprises: (a) dividing a data page into K regions; (b) initial filter values for each region {

} To a value of 1 to 2; (c) filter values for each region {

}, calculating a bit error ratio (BER) of a data page after applying n (n is a repetition number, n is a natural number of 1 or more) to the data page; (d) adding a filter value {

Calculating a bit error rate (BER) of a data page; And (e) subtracting the bit error ratio (BER) calculated in the step (c) from the bit error ratio (BER) calculated in the step (d) (B) determining an optimized filter value and returning to step (c) again if the value is negative, repeating steps (c) through (e) until an optimized filter value is determined And is set to the determined filter value.

}을 1 내지 2의 값으로 설정하는 단계; (c) 각 영역에 대한 필터 값 {

}, (n은 반복횟수, n은 1 이상의 자연수)을 상기 데이터 페이지에 적용한 후, 데이터 페이지의 비트 에러 비율(BER)을 연산하는 단계; (d) 상기 필터 값에 일정 스텝 h 만큼 더해진 필터 값 {

}을 적용한 후 데이터 페이지의 비트 에러 비율(BER)을 연산하는 단계; 및 (e) 상기 (d)단계에서 연산한 비트 에러 비율(BER)에서 (c)단계에서 연산한 비트 에러 비율(BER)을 차감하여 그 값이 양수이면 (d)단계에서 연산한 비트 에러 비율(BER)을 최적화된 필터값으로 결정하고 그 값이 음수이면 다시 (c)단계로 다시 되돌아가는 단계;를 포함하며, 최적화된 필터값이 결정될 때까지 상기 (c) 내지 (e) 단계가 반복되고, 상기 결정된 필터값으로 설정되는 것을 특징으로 한다.A method of setting a recursive image filter according to the present invention is a program recorded on a recording medium readable by an electronic device. The recording medium includes: (a) dividing a data page into K areas; (b) initial filter values for each region {

} To a value of 1 to 2; (c) filter values for each region {

}, calculating a bit error ratio (BER) of a data page after applying n (n is a repetition number, n is a natural number of 1 or more) to the data page; (d) adding a filter value {

Calculating a bit error rate (BER) of a data page; And (e) subtracting the bit error ratio (BER) calculated in the step (c) from the bit error ratio (BER) calculated in the step (d) (B) determining an optimized filter value and returning to step (c) again if the value is negative, repeating steps (c) through (e) until an optimized filter value is determined And is set to the determined filter value.

An apparatus for recording and reproducing information on a holographic data storage of the present invention includes: an encoding unit for binarizing a two-dimensional original image of the present invention and converting the two-dimensional original image into a two-dimensional data page; An optical unit which removes high frequency region information of the two-dimensional data page using a Nyquist aperture and a lens; A recording unit for recording the high frequency removed two-dimensional data page on a holographic disk; A filter unit for applying a recursive image filter to the two-dimensional data page; And a sensor unit for acquiring a data page to which the recursive image filter is applied in the image sensor.

In the encoding unit, the two-dimensional original image is binarized by using a modulation code.

}을 1 내지 2의 값으로 설정하는 단계; (c) 각 영역에 대한 필터 값 {

}, (n은 반복횟수, n은 1 이상의 자연수)을 상기 데이터 페이지에 적용한 후, 데이터 페이지의 비트 에러 비율(BER)을 연산하는 단계; (d) 상기 필터 값에 일정 스텝 h 만큼 더해진 필터 값 {

}을 적용한 후 데이터 페이지의 비트 에러 비율(BER)을 연산하는 단계; 및 (e) 상기 (d)단계에서 연산한 비트 에러 비율(BER)에서 (c)단계에서 연산한 비트 에러 비율(BER)을 차감하여 그 값이 양수이면 (d)단계에서 연산한 비트 에러 비율(BER)을 최적화된 필터값으로 결정하고 그 값이 음수이면 다시 (c)단계로 다시 되돌아가는 단계;를 포함하며, 최적화된 필터값이 결정될 때까지 상기 (c) 내지 (e) 단계가 반복되고, 상기 결정된 필터값으로 설정된 것을 반영한 공간 광 변조기를 이용한 물리적인 이미지 필터인 것을 특징으로 한다.In the filter section, the recursive image filter comprises: (a) dividing a data page into K regions; (b) initial filter values for each region {

} To a value of 1 to 2; (c) filter values for each region {

}, calculating a bit error ratio (BER) of a data page after applying n (n is a repetition number, n is a natural number of 1 or more) to the data page; (d) adding a filter value {

Calculating a bit error rate (BER) of a data page; And (e) subtracting the bit error ratio (BER) calculated in the step (c) from the bit error ratio (BER) calculated in the step (d) (B) determining an optimized filter value and returning to step (c) again if the value is negative, repeating steps (c) through (e) until an optimized filter value is determined And is a physical image filter using a spatial light modulator reflecting the set value of the filter value.

The step (a) is characterized by dividing the data page into K regions with a boundary of one or more concentric concentric circles based on the center of the data page.

The one or more concentric circles may be formed at various intervals, but may be spaced apart from each other by a predetermined distance, or may be formed with decreasing spacing between concentric circles as the size increases.

In another embodiment, the step (a) is a step of dividing a data page into K regions with boundaries of at least one rectangle having various sizes based on the center of the data page.

In addition, the at least one rectangle may be formed at various intervals, but may be formed at a predetermined interval, or may be formed to have a reduced spacing between the rectangles as the size increases.

In yet another embodiment, the step (a) is a step of dividing a data page into K areas with one or more diverse diamond shapes having a different size as a reference on the basis of the center of the data page.

The at least one diamond shape may be formed at various intervals, but may be formed with a predetermined spacing, or may be formed with decreasing distance between diamonds as the size increases.

}은 모두 같은 값인 것을 특징으로 한다.Then, the initial filter value {

} Are all the same value.

Further, the constant step h value is set to a value exceeding 0 and 1 or less.

By using a recursive image filter in a holographic data storage system, there is an effect of significantly reducing the ratio of bit errors caused by Nyquist diaphragms, thereby improving the recording density of the holographic disk.

As shown in FIG. 3, a general digital image has different frequency information according to an image, whereas a two-dimensional binary image used in a holographic data storage has a characteristic that a shape is uniform and frequency information has a uniform distribution The advantage is that you can design an image filter that is not affected by the image or system.

By designing a recursive image filter using a numerical analytical method, it is possible to implement a miniaturized system without modification of existing optical systems.

1 is a flowchart showing a process of recording and reproducing information in a holographic data storage;
2 is a block diagram showing an optical system for recording and reproducing holographic data storage;
3 is a graph showing frequency information of an image used in a general digital image and holographic data storage.
4 is a flowchart illustrating a process of designing a recursive image filter.
FIG. 5 is a diagram illustrating a method of dividing a region concentric to a boundary in a recursive image filter design; FIG.
FIG. 6 is a diagram illustrating a method of dividing a region by a rectangle into a boundary in a recursive image filter design; FIG.
FIG. 7 is a diagram illustrating a method of dividing a diamond shape into boundary regions in the design of a recursive image filter; FIG.
Figure 8 is a graph showing a reduction in bit error during recording and playback of holographic data storage using a recursive image filter.
9 is a block diagram showing an example in which a numerical recursive image filter is implemented as a physical image filter and used in an optical system.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the scope of the present invention is not limited thereto. In the description of the present invention, a detailed description of known configurations will be omitted, and a detailed description of configurations that may unnecessarily obscure the gist of the present invention will be omitted.

1 is a flowchart illustrating a process of recording and reproducing information in a holographic data storage. According to an embodiment of the present invention, there is provided a method of recording and reproducing information in a holographic data storage, the method comprising: encoding a two-dimensional original image into a two-dimensional data page; A high frequency removing step of removing high frequency region information of the two-dimensional data page using a Nyquist aperture; An image acquiring step of acquiring the high frequency removed two-dimensional data page from the image sensor; A digitizing step of applying an image recursively filtered by the image sensor; And a decoding step of reproducing the recursively filtered data page as two-dimensional original data.

In the encoding step, the two-dimensional original image is binarized and converted into a two-dimensional data page. A code commonly used in a holographic data storage device is a balance code having the same number of ON pixels and OFF pixels. Signs with code rates of 8/12, 3/4, 5/6, 6/8, etc. may be used depending on the data size. In the embodiment of the present invention, a 2-dimensional original image is binarized using a 6/8 modulation code. A 6/8 modulation code can be a 1x8 vector form or a 2x4 matrix form of the codeword.

Using the 6/8 modulation code, the binarized data page is recorded on the holographic disk through the optical system in the form of interference fringes of the signal beam and the reference beam. By adjusting the angle of the reference beam through the galvano mirror, it is possible to store several holograms on the holographic disk.

는 Nyquist factor, λ는 빔의 파장, f는 렌즈의 초점거리 및 .

는 공간 광 변조기의 픽셀 크기를 의미한다.Also, place the Nyquist aperture on the Fourier plane of the lens through which the beam passes prior to recording holographic discs. The Nyquist diaphragm passes only the low frequencies of a two-dimensional data page and removes high frequency domain information. Compared with the low frequency, the recording density of the holographic disk can be increased by removing the high frequency which is the noise signal. The frequency range of the removed high frequency is variable depending on the size of the Nyquist factor used. The size of the Nyquist factor is proportional to the diameter of the Nyquist aperture. That is, the size of the Nyquist factor and the diameter of the Nyquist aperture are given by the following equations. Where D is the size of the Nyquist aperture,

Is the Nyquist factor, λ is the wavelength of the beam, f is the focal length of the lens, and.

Means the pixel size of the spatial light modulator.

Thereafter, the two-dimensional data page, which is high frequency removed by the Nyquist aperture, is reproduced in the image sensor. The image sensor may be a CMOS sensor or a CCD. In the step of reproducing the hologram recorded on the holographic disk in the image sensor, only the reference beam is used. In the embodiment of the present invention, a CMOS sensor having a pixel size of 12 mu m was used.

Thereafter, in the digitizing step, the image obtained by the image sensor is converted into a data page of a binary format again. The initially acquired image in the image sensor contains a bit error. The bit error is a ratio of the number of transmitted bits to the number of errored bits. The bit error is an error that necessarily occurs while passing through an optical system such as a Nyquist diaphragm and a lens. To reduce the bit error rate and increase the recording density of the holographic data storage, a recursive image filter is applied to the initially acquired image in the image sensor.

4 is a flowchart illustrating a process of designing a recursive image filter. The recursive image filter is set in the following order.

S101: The data page is divided into K regions. Preferably, as shown in FIG. 5, it is preferable to divide the data page into K regions with a boundary of one or more concentric concentric circles based on the center of the data page. Not only one or more concentric circles are formed spaced apart from each other by a predetermined distance but also the spacing between the concentric circles is reduced as the size of the concentric circles increases. As shown in FIGS. 6 and 7, it is possible to divide the area into various shapes such as a rectangular shape and a diamond shape as well as the concentric shape, and the shape of the area is not limited.

}을 1 내지 2의 값으로 설정한다. ω의 좌밑첨자는 반복 회수를 의미하며, 우밑첨자는 각각의 영역을 의미한다. 모든 영역의 초기 필터 값이 같은 값으로 설정되는 것이 바람직하나, 다른 값으로 설정되는 것도 가능하다.S102: initial filter value for each divided area {

} Is set to a value of 1 to 2. The lower-case subscript of? denotes the number of repetitions, and the lower-case subscript denotes each area. It is preferable that the initial filter values of all regions are set to the same value, but it is also possible to set them to different values.

}, (n은 반복횟수, n은 1 이상의 자연수)으로 구성된 필터를 상기 데이터 페이지에 적용한 후, 데이터 페이지의 비트 에러 비율(BER)을 연산한다. S103: At the n-th stage for each region, the filter value {

}, (n is a repetition number, and n is a natural number equal to or greater than 1) to the data page, and then calculates a bit error ratio (BER) of the data page.

}에 일정 스텝 h 만큼 더해진 필터 값 {

}을 적용한 후 데이터 페이지의 비트 에러 비율(BER)을 연산한다. 여기서 일정 스텝 h는 0 초과 1 이하인 수인 것이 바람직하다. 즉, 하기 식과 같은 관계가 성립한다.S104: At the n-th stage for each region, the filter value {

} To the filter value {

} And then calculates the bit error rate (BER) of the data page. Here, it is preferable that the predetermined step h is a number exceeding 0 and not exceeding 1. That is, the following relationship is established.

Since the above equations are applied in common to all K regions, the subscripts can be omitted.

Step S105: If the bit error ratio (BER) calculated in the n-th stage is subtracted from the bit error ratio (BER) calculated in the (n + 1) th stage and the value is positive, the bit error rate If the target filter value is negative, the process returns to step S103 again and repeats steps S103 to S105.

Steps S103 to S105 are repeated until the optimized target filter value is determined, and the recursive image filter is set to the optimized target filter value.

As described above, by designing the recursive image filter using a numerical analysis method, it is possible to realize a miniaturized system without modification of the existing optical system.

In addition, since a general digital image has different frequency information depending on an image, a two-dimensional binarized image used in holographic data storage has a characteristic that its shape is uniform and frequency information has a uniform distribution, It is possible to design a recursive image filter which is not affected by the image.

Further, as shown in FIG. 8, the use of a recursive image filter in the holographic data storage system has the effect of significantly reducing the ratio of bit errors caused by Nyquist diaphragms, thereby improving the recording density of the holographic disk .

The recursive image filter is an intensity filter. In order to apply a filter to an image, a filter and an image are respectively Fourier-transformed, then the two are multiplied, or they are convoluted in the image region.

Finally, in the decoding step, the data page to which the filter composed of the determined optimization filter value is applied is again decoded into the two-dimensional original data through the 6/8 modulation code.

}을 1 내지 2의 값으로 설정하는 단계; (c) 각 영역에 대한 필터 값 {

}, (n은 반복횟수, n은 1 이상의 자연수)을 상기 데이터 페이지에 적용한 후, 데이터 페이지의 비트 에러 비율(BER)을 연산하는 단계; (d) 상기 필터 값에 일정 스텝 h 만큼 더해진 필터 값 {

}을 적용한 후 데이터 페이지의 비트 에러 비율(BER)을 연산하는 단계; 및 (e) 상기 (d)단계에서 연산한 비트 에러 비율(BER)에서 (c)단계에서 연산한 비트 에러 비율(BER)을 차감하여 그 값이 양수이면 (c)단계에서 연산한 비트 에러 비율(BER)을 최적화된 목표 필터 값으로 결정하고 그 값이 음수이면 다시 (c)단계로 다시 되돌아가는 단계;를 포함하며, 최적화된 목표 필터 값이 결정될 때까지 상기 (c) 내지 (e) 단계가 반복되고, 상기 결정된 필터 값으로 재귀적 이미지 필터를 설정하는 방법이 프로그램화된 것을 특징으로 한다. 각 단계의 상세한 설명은 상기 기재되어 있는 바, 여기서는 생략하도록 한다.A method of setting a recursive image filter, which is another embodiment of the present invention, includes the steps of: (a) dividing a data page into K regions; (b) initial filter values for each region {

} To a value of 1 to 2; (c) filter values for each region {

}, calculating a bit error ratio (BER) of a data page after applying n (n is a repetition number, n is a natural number of 1 or more) to the data page; (d) adding a filter value {

Calculating a bit error rate (BER) of a data page; And (e) subtracting the bit error ratio (BER) calculated in the step (c) from the bit error ratio (BER) calculated in the step (d) (B) determining an optimized target filter value and returning to step (c) again if the value is negative, wherein the steps (c) through (e) And a method of setting a recursive image filter as the determined filter value is characterized by being programmed. The detailed description of each step is as described above, and will not be described here.

An apparatus for recording and reproducing information in a holographic data storage, which is another embodiment of the present invention, includes an encoding unit for binarizing a two-dimensional original image and converting the two-dimensional original image into a two-dimensional data page; An optical unit which removes high frequency region information of the two-dimensional data page using a Nyquist aperture and a lens; A recording unit for recording the high frequency removed two-dimensional data page on a holographic disk; A filter unit for applying a recursive image filter to the two-dimensional data page; And a sensor unit for acquiring a data page to which the recursive image filter is applied in the image sensor.

The recursive image filter of the filter unit may be used as a physical image filter 80 using a spatial light modulator reflecting a numerical recursive image filter. FIG. 9 shows an apparatus for recording and reproducing information on a holographic data storage using a physical image filter 80. The encoding unit displays the two-dimensional data to be recorded on a spatial light modulator (SLM) 10 and reflects the two-dimensional data on the phase of the signal beam. In the optical section, the signal beam is focused on the holographic disk 40 after passing through the primary Fourier lens 50, the physical Nyquist diaphragm 30 and the secondary Fourier lenses 61 and 62. The reference beam also passes through the lens to focus on the holographic disk 40. The hologram generated by interfering the focal point information of the signal beam with the reference beam is recorded in the holographic disk 40 of the recording section. At this time, if the incident angle of the reference beam is adjusted through the galvanometer mirror 20, it is possible to record a plurality of holograms at the same position. Only the reference beam is used when reproducing the recorded information of the holographic disk 40. [ The reference beam is reproduced in the image sensor of the sensor section through the third Fourier lenses 101 and 102, the physical image filter 80 of the filter section and the fourth Fourier lens 103. [

In the foregoing detailed description of the present invention, only specific embodiments thereof have been described. It is to be understood, however, that the invention is not to be limited to the specific forms thereof, which are to be considered as being limited to the specific embodiments, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. .

10: spatial light modulator 20: galvano mirror
30: physical Nyquist aperture 40: holographic disk
50: primary Fourier lens 61, 62: secondary Fourier lens
71, 72: Reference light lens 80: Physical image filter
90: Image sensor 101, 102: Third order Fourier lens
103: Fourth order Fourier lens

Claims (40)

An encoding step of binarizing the two-dimensional original image and converting the two-dimensional original image into a two-dimensional data page;
A high frequency removing step of removing high frequency region information of the two-dimensional data page using a Nyquist aperture;
An image acquiring step of acquiring the high frequency removed two-dimensional data page from the image sensor;
A digitizing step of applying a recursive image filter to a data page acquired by the image sensor; And
And reproducing the data page to which the recursive image filter is applied as two-dimensional original data. In the encoding step of claim 1,
A method for recording and reproducing information in a holographic data storage, characterized in that a two-dimensional original image is binarized using a modulation code. In the digitizing step of claim 1,
Wherein the recursive image filter comprises:
(a) dividing a data page into K regions (K is a natural number of 1 or more);
(b) initial filter values for each region {

} To a value of 1 to 2;
(c) filter values for each region {

}, calculating a bit error ratio (BER) of a data page after applying n (n is a repetition number, n is a natural number of 1 or more) to the data page;
(d) a filter value added to the filter value by a predetermined step h (h is a number equal to or larger than 0 and equal to or smaller than 1)

Calculating a bit error rate (BER) of a data page; And
(e) a bit error ratio (BER) calculated in the step (c) is subtracted from the bit error ratio (BER) calculated in the step (d), and if the value is positive, the bit error rate BER) as a target filter value, and if the value is negative, returning to step (c) again,
Wherein the steps (c) to (e) are repeated until the target filter value is determined and set to the determined filter value. The method of claim 3,
The step (a)
Dividing the data page into the K regions with boundaries of one or more concentric concentric circles based on the center of the data page. ≪ Desc / Clms Page number 19 > 5. The method of claim 4,
Wherein the at least one concentric circle is spaced apart at a predetermined interval. 5. The method of claim 4,
Wherein the at least one concentric circle is formed to have a reduced spacing between concentric circles as the size increases. The method of claim 3,
The step (a)
Dividing a data page into at least one of the K regions with a border of one or more different sized squares based on the center of the data page. ≪ RTI ID = 0.0 > 11. < / RTI > 8. The method of claim 7,
Wherein the at least one rectangle is spaced apart from the holographic data storage at a predetermined interval. 8. The method of claim 7,
Wherein the at least one rectangle is formed with decreasing spacing between the rectangles as the size increases. The method of claim 3,
The step (a)
Dividing a data page into K regions with boundaries of one or more different sizes of diamond shapes with respect to the center of the data page. ≪ RTI ID = 0.0 > 15. < / RTI > 11. The method of claim 10,
Wherein the at least one diamond shape is spaced apart from the holographic data storage by a predetermined distance. 11. The method of claim 10,
Wherein the at least one diamond shape is formed with decreasing spacing between diamond shapes as the size increases. The method of claim 3,
The initial filter value {

≪ / RTI > are all equal in value. delete (a) dividing a data page into K regions (K is a natural number of 1 or more);
(b) initial filter values for each region {

} To a value of 1 to 2;
(c) filter values for each region {

}, calculating a bit error ratio (BER) of a data page after applying n (n is a repetition number, n is a natural number of 1 or more) to the data page;
(d) a filter value added to the filter value by a predetermined step h (h is a number equal to or larger than 0 and equal to or smaller than 1)

Calculating a bit error rate (BER) of a data page; And
(e) a bit error ratio (BER) calculated in the step (c) is subtracted from the bit error ratio (BER) calculated in the step (d), and if the value is positive, the bit error rate BER) as a target filter value, and if the value is negative, returning to step (c) again,
(C) repeating the steps (c) to (e) until the target filter value is determined, and setting a recursive image filter to set the filter with the determined filter value, . 16. The method of claim 15,
The step (a)
Dividing the data page into the K regions with a boundary of one or more concentric concentric circles relative to the center of the data page as a boundary. The method of setting a recursive image filter, Possible recording medium. 17. The method of claim 16,
Wherein the one or more concentric circles are spaced apart from each other by a predetermined distance. ≪ Desc / Clms Page number 19 > 17. The method of claim 16,
Wherein the spacing between the concentric circles is reduced as the size of the at least one concentric circle increases. ≪ Desc / Clms Page number 19 > 16. The method of claim 15,
The step (a)
Dividing the data page into the K regions with a border of one or more different sized squares based on the center of the data page as the boundary. The method of setting a recursive image filter, Possible recording medium. 20. The method of claim 19,
Wherein the at least one rectangle is spaced apart by a predetermined distance. A recording medium readable by a program, the method comprising: 20. The method of claim 19,
Wherein the at least one rectangle is formed by decreasing the spacing between the rectangles as the size of the at least one rectangle increases. 16. The method of claim 15,
The step (a)
And dividing the data page into K areas by boundary of one or more diamond-shaped diamonds with a center of the data page as a boundary. The method of setting a recursive image filter according to claim 1, Readable recording medium. 23. The method of claim 22,
Characterized in that the at least one diamond shape is formed spaced apart from each other by a predetermined distance. ≪ Desc / Clms Page number 19 > 23. The method of claim 22,
Wherein the at least one diamond shape is formed by decreasing the distance between diamond shapes as the size is increased. ≪ Desc / Clms Page number 19 > 16. The method of claim 15,
The initial filter value {

} Are all the same value. A method of setting a recursive image filter, comprising the steps of: delete An encoding unit for binarizing the two-dimensional original image and converting the two-dimensional original image into a two-dimensional data page;
An optical unit which removes high frequency region information of the two-dimensional data page using a Nyquist aperture and a lens;
A recording unit for recording the high frequency removed two-dimensional data page on a holographic disk;
A filter unit for applying a recursive image filter to the two-dimensional data page;
And a sensor unit for acquiring a data page to which the recursive image filter is applied in an image sensor. The encoding unit of claim 27,
A method for recording and reproducing information in a holographic data storage, characterized in that a two-dimensional original image is binarized using a modulation code. The filter unit of claim 27,
Wherein the recursive image filter comprises:
(a) dividing a data page into K regions (K is a natural number of 1 or more);
(b) initial filter values for each region {

} To a value of 1 to 2;
(c) filter values for each region {

}, calculating a bit error ratio (BER) of a data page after applying n (n is a repetition number, n is a natural number of 1 or more) to the data page;
(d) a filter value added to the filter value by a predetermined step h (h is a number equal to or larger than 0 and equal to or smaller than 1)

Calculating a bit error rate (BER) of a data page; And
(e) a bit error ratio (BER) calculated in the step (c) is subtracted from the bit error ratio (BER) calculated in the step (d), and if the value is positive, the bit error rate BER) as a target filter value, and if the value is negative, returning to step (c) again,
Wherein the step (c) to (e) are repeated until the target filter value is determined, and the physical image filter is a physical image filter using a spatial light modulator reflecting the set value of the determined filter value. A device for recording and reproducing. 30. The method of claim 29,
The step (a)
And dividing the data page into the K areas with the boundary of one or more concentric concentric circles based on the center of the data page as a boundary. 31. The method of claim 30,
Wherein the one or more concentric circles are spaced apart from each other by a predetermined distance. 31. The method of claim 30,
Wherein the one or more concentric circles are formed with decreasing spacing between concentric circles as the size increases. 30. The method of claim 29,
The step (a)
And dividing the data page into the K regions with boundaries of at least one rectangle of various sizes based on the center of the data page. 34. The method of claim 33,
Wherein the at least one rectangle is spaced apart from the holographic data storage at a predetermined interval. 34. The method of claim 33,
Wherein the at least one rectangle is formed to have a reduced spacing between the rectangles as the size of the at least one rectangle increases. 30. The method of claim 29,
The step (a)
Wherein the step of dividing the data page into the K areas is performed by dividing the data page into at least one of a plurality of types of diamond shapes based on the center of the data page. 37. The method of claim 36,
Wherein the at least one diamond shape is spaced apart from the holographic data storage at a predetermined interval. 37. The method of claim 36,
Wherein the at least one diamond shape is formed with decreasing spacing between diamond shapes as the size increases. 30. The method of claim 29,
The initial filter value {

Are all the same. ≪ RTI ID = 0.0 > 1 < / RTI > delete

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