KR100578206B1 - Apparatus for compensating recording image's unmatching therefor of a holographic digital data system - Google Patents

Abstract

The present invention relates to an unmatched correction device of a holographic digital data system, and in particular, the device according to the present invention includes a data image, an edge of an all-off value, and an x- and y-axis consisting of three pixels of all-on values. A device that compensates for mismatching between a reproduced image and CCD pixels by reproducing hologram data recorded on a storage medium as an interference fringe by interfering a signal light and a reference light modulated with an in mark with signal light, wherein four pixels are arranged in a diamond shape. A first alignment mark extracting unit configured to receive reproduction light output from the pixels corresponding to the x-axis alignment mark as four pixels and to extract and provide light quantity information of the four pixels during data reproduction; Four pixels are arranged in a diamond shape, and the data is output from the pixels corresponding to the y-axis align mark during data playback. The second alignment mark extractor which receives the light into four pixels and extracts and provides information on the amount of light of the four pixels, and compares the quantity of light information of the four pixels provided by the first alignment mark extractor. Non-matching for determining whether there is a vertical mismatch between the reproduced image and the CCD pixels, and determining whether there is a left / right mismatch between the reproduced image and the CCD pixels by comparing light quantity information on four pixels provided by the second alignment mark extractor. It includes a detection unit.

Description

Asymmetry correction device of holographic digital data system {APPARATUS FOR COMPENSATING RECORDING IMAGE'S UNMATCHING THEREFOR OF A HOLOGRAPHIC DIGITAL DATA SYSTEM}

1 is a block diagram of a typical holographic digital data system,

2 is a diagram showing one page information reproduced from a storage medium in a conventional holographic digital data system;

3 is a block diagram showing a holographic digital data system according to the present invention;

4 is a view showing a position where an alignment mark applied to the present invention is recorded;

5 is a block diagram showing a mismatch correction device of the reproduced image of the holographic digital data system according to the present invention;

6A-6B illustrate the structure of an alignment mark detector in accordance with the present invention.

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

102: light source 108: optical separator

118, 122 mirror 110: data pattern

112: alignment mark 124: storage medium

128: CCD 130: Played image

140: first alignment mark detection unit 142: second alignment mark detection unit

144: mismatch detection unit 146: control block

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holographic digital data storage system (HDDS), and more particularly to a mismatch correction device of a holographic digital data system.

Recently, technologies for storing holographic digital data have been actively researched in various fields, for example, thanks to remarkable developments such as semiconductor lasers, charge coupled devices (CCDs), and liquid crystal displays (LCDs). As a result, fingerprint recognition systems for storing and reproducing fingerprints have been put to practical use, and are being expanded to various fields that can apply the advantages of large storage capacity and ultra-high data transfer speed. Among them, a holographic digital data system storing a large amount of data is a storage medium, for example, optical refraction, in which an interference fringe generated when the signal light from the target object and the reference light are interfered with each other is sensitive to the amplitude of the interference fringe. By recording to a storage medium such as a photorefractive crystal, it is possible to display a three-dimensional image of an object, and also to display hundreds to thousands of hologram data composed of pages of binary data. Can be stored in place.

1 is a block diagram of a general holographic digital data system. Referring to FIG. 1, a general holographic digital data system is installed at a position corresponding to a light source 12 and a light source 12 for generating a laser light, so that the light of the light source 12 is referred to as a reference beam and a signal beam. a beam splitter 18 separating the beam into a beam, a mirror 32 reflecting the reference light separated from the light splitter 20, and light reflected from the mirror 32 is incident on the storage medium 10. Spatial Light Modulator (SLM) that carries input data, that is, binary data of a plurality of pixels configured in units of pages, on the signal light separated by the rotating mirror 36 and the optical separator 20 for converting the angles to be converted. (26), the interference fringe generated by the interference of the signal light output from the spatial light modulator (SLM) 26 and the reference light reflected by the rotation mirror 36 is recorded and diffracted and outputs the interference fringe recorded by irradiation of the reference light. Storage medium 10, write to storage medium 10 And a CCD 42 for reproducing a one-page binary pixel data image recorded in the form of an interference fringe on the storage medium by irradiating quasi-light only, and converting the reproduced data image into electrical data and outputting the same. Unexplained reference numeral 14 denotes an optical magnification lens, 34 denotes a retardation lens, and 30 and 40 denote Fourier lenses.

The holographic digital data system thus constructed operates as follows.

The laser light irradiated from the light source 12 is divided into reference light and signal light in the light separator 18. At this time, the signal light is input to the spatial light modulator 26 and modulated. That is, the signal light is input to the storage medium 10 after the data input from the spatial light modulator 26 is modulated in units of one page of the binary data of the intensity of actual pixels. In addition, the reference light is incident on the storage medium 10 at an angle changed by the rotation mirror 32. That is, the reference light which slightly changes the angle of the rotation mirror 32 corresponding to each page is incident on the storage crystal 10 which is the storage medium 10. The signal light and the reference light cause interference inside the storage medium 10 for recording the hologram, and light-induced generation of mobile charge of the internal kinetic charge of the storage medium 10 according to the intensity of the interference fringe generated at this time. Is generated and an interference fringe is recorded through this process.

In order to read the data recorded in the storage medium 10, only the reference light needs to be irradiated to the storage medium 10. That is, when the reproduction reference light having the same deflection angle as the deflection angle of the recording reference light enters the storage medium 10 on which the interference data is recorded, the reproduction reference light is diffracted to make a single page of binary data (consisting of the original pixel contrast ( That is, the checkerboard pattern) is restored. The binary data (one page unit) reproduced from the storage medium 10 is restored to the original data through the CCD 42, the signal processing unit (not shown), the decoder (not shown), and the like.

In the related art, in order to restore the image data in units of pages reproduced from the storage medium 10, that is, binary pixel data, to the original data through the CCD 42 or the like, a signal matching process of 1: 1 matching has been performed. That is, the pixel of the image reproduced in the storage medium 10 and the pixel of the CCD 42 array are matched 1: 1 to restore original pixel data. However, in a shift multiplexing system employing 1: 1 pixel matching, when the size error between the reproduced image and the CCD pixel is 1/2 of the CCD pixel size, severe degradation of the data detected by the CCD 42 array occurs. This results in an inability to obtain the stored data correctly.

In order to prevent this, the conventional system oversamples one pixel of the reproduced image of the storage medium 10 to nine pixels (3 ㅧ 3) of the CCD 42 array, and restores only one pixel data centered among them to the original data. Technology has emerged.

Meanwhile, referring to FIG. 2, when one page information reproduced from a storage medium in a conventional holographic digital data system has a size of, for example, 1024 × 1024, a data area 100 of 720 × 720 is present in a center portion of a page. A frame area 200 with pixels always ON exists in the outer part of the page, which is the periphery of the data area, and is used as information for separating the data area. That is, when one pixel of a reproduced image of a storage medium is oversampled by nine pixels of a 3x3 CCD array, only pixels of the reproduced image corresponding to the data region except the frame region are oversampled by the 3x3 CCD array. .

However, in the holographic digital data system according to the prior art, in spite of the above oversampling method, mismatching between the pixels of the reproduced image and the pixels of the CCD array occurs due to the interference effect between the pixels. There was a difficult problem.

SUMMARY OF THE INVENTION An object of the present invention is to record holographic digital data in which an alignment mark is inserted into a storage medium by using a spatial light modulator, and to align the alignment mark in an image reproduced during reproduction. Provides a mismatch correction device of a holographic digital data system that can more accurately measure the mismatch between a reproduced image and a CCD pixel by detecting a misalignment between an alignment mark pixel and a CCD pixel after detection by a diamond-shaped detector. It is.

In order to achieve the above object, the present invention, by interfering the signal light and the reference light modulated by the signal light of the alignment mark on the x, y-axis consisting of a data image, a border having all of the off value, and three pixels of all on value to the signal light A device for compensating for mismatching between a reproduced image and CCD pixels by reproducing hologram data recorded on a storage medium as an interference fringe, wherein four pixels are arranged in a diamond shape and corresponding to the x-axis alignment mark during data reproduction. A first alignment mark extractor configured to receive reproduction light output from the pixels into the four pixels, extract and provide light quantity information of the four pixels, and four pixels are arranged in a diamond shape, When the data is reproduced, the reproduction light output from the pixels corresponding to the y-axis alignment mark is received by the four pixels, and the four The upper and lower ratios of the reproduction image and the CCD pixels through comparison between the second alignment mark extracting unit extracting and providing the respective light quantity information of the pixels and the light quantity information of the four pixels provided by the first alignment mark extracting unit. And a mismatch detector configured to determine whether there is a match and determine whether there is left or right mismatch between the reproduced image and the CCD pixels by comparing light quantity information of four pixels provided by the second alignment mark extractor.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

3 is a block diagram illustrating a holographic digital data system according to the present invention, and FIG. 4 is a diagram showing hologram data in which an align mark is inserted according to an exemplary embodiment of the present invention.

Referring to FIG. 3, a holographic digital data system according to the present invention is installed at a light source 102 for generating a laser light and a position corresponding to the light source 102 to separate light from the light source 102 into reference light and signal light. The optical splitter 108, the mirror 118 reflecting the reference light separated by the optical splitter 108, and the rotating mirror for changing the angle at which the light reflected from the mirror 118 is incident on the storage medium 124. And a pixel having a value of ON while carrying a holographic digital data pattern, i.e., a binary data pattern 110 of a plurality of pixels configured in units of pages, on the signal light separated by the optical separator 108. And a signal light output from the spatial light modulator (SLM) 114 and the spatial light modulator (SLM) 114 that input the x and y axis alignment marks 112 respectively inserted in the x and y axes of the edge. And interference due to reference light reflected from the rotating mirror 122 And a storage medium 124, the interference fringe recorded.

That is, in the hologram data stored in the storage medium 104, as shown in FIG. 4, the x-axis and y-axis alignment marks 112 on the x-axis and y-axis of the edge 402 surrounding the data pattern 110, respectively. ), The alignment mark 112 is composed of three pixels, all of which are on.

Here, the alignment mark 112 in the x-axis direction is for correcting misalignment in the vertical direction between the pixel of the CCD 128 and the reproduced image, and the alignment mark 112 in the y-axis direction is connected to the CCD pixel. This is for correcting misalignment in left and right directions between playback images.

In the preferred embodiment of the present invention, although one example is recorded in each of the x-axis direction and the y-axis direction, a plurality of elements are formed in the border 402 by being arranged in succession, or between the border 402 and the data pattern 110. Can be placed on.

In the system of the present invention, the alignment medium is reproduced together with the data image recorded in the form of an interference fringe when only the reference light is irradiated while the signal medium is blocked. In addition, the system of the present invention, including the CCD 128, photographs the data image and the alignment mark reproduced from the storage medium 124, converts it into an electrical data signal, and outputs the converted data. In the meantime, reference numeral 104 denotes an optical magnification lens, 120 denotes a retardation lens, and 116 and 126 denote Fourier lenses.

The holographic digital data system according to the present invention thus constructed operates as follows during recording.

The laser light irradiated from the light source 102 is divided into the reference light and the signal light in the light separator 108. At this time, the signal light is input to the spatial light modulator (SLM) 114 and modulated. However, the signal light is composed of three pixels having a value of ON together with the holographic digital data pattern 110 input from the spatial light modulator (SLM) 114 and inserted into the x and y axes of the edge, respectively, The y-axis align mark 112 is incident on the storage medium 124 after being modulated in units of one page of the binary data of the intensity of real pixels. In addition, the reference light is incident on the storage medium 124 at an angle changed by the rotation mirror 122. That is, the reference light which slightly changes the angle of the rotation mirror 122 corresponding to each page is incident on the crystal which is the storage medium 124. The reference light and the signal light modulated by the spatial light modulator (SLM) 114 cause interference within the storage medium 124 for recording the hologram, so that an interference fringe is recorded in the storage medium 124.

The holographic digital data system according to the present invention irradiates the storage medium 124 with only the reference light separated by the optical separator 108 while blocking the signal light in order to read the data recorded on the storage medium 124 during reproduction. When the reproduction reference light having the same deflection angle as that of the recording reference light enters the storage medium 124, the reproduction reference light is diffracted in the storage medium 124 to reproduce the binary data of the reproduced image composed of the original pixel contrast. In this case, the reproduced data includes an alignment mark for detecting mismatching or matching between the reproduced image and the CCD pixel.

In the system of the present invention, the image reproduced from the storage medium 124 includes an alignment mark 112 together with a data pattern 110 modulated by a spatial light modulator (SLM).

5 is a block diagram illustrating a mismatch correcting apparatus for a reproduced image of the holographic digital data system according to the present invention.

Referring to FIG. 5, in the holographic digital data system according to the present invention, the mismatch correction apparatus includes a CCD 128 array for capturing an image reproduced from a storage medium, converting the image into electrical data, and outputting four pixels. A first array that is arranged in a shape and receives reproduction light output from the pixels corresponding to the x-axis alignment mark 112 as four pixels during data reproduction, and extracts and provides light quantity information of the four pixels. The in-mark extractor 140 and four pixels are arranged in a diamond shape, and the reproduction light output from the pixels corresponding to the y-axis alignment mark 112 is received as four pixels during data reproduction. The second align mark extracting unit 142 extracts and provides the respective light quantity information of the four pixels, and compares the amount of light information about the four pixels provided by the first align mark extracting unit 140. Determine whether there is no top-down mismatch between the raw image and the CCD pixels, and determine left / right mismatch between the reproduced image and the CCD pixels by comparing light quantity information on the four pixels provided by the second alignment mark extractor 142. It includes a mismatch detection unit 144.

Here, the structure of the 1st, 2nd alignment mark extraction part 140, 142 is demonstrated with reference to FIGS. 6A-6B.

First, as illustrated in FIG. 6A, the first alignment mark extractor 140 arranges four pixels in a diamond shape, that is, one pixel on the left and right sides of the center pixels 2 and 3 (1, 4) arranged, and by comparing the center pixels (2, 3) and the left and right pixels (1, 4) it is possible to determine whether there is a vertical mismatch between the playback image and the CCD pixels.

As shown in FIG. 6B, the second alignment mark extractor 140 has four pixels arranged in a diamond shape in the same manner as the first alignment mark extractor 140. In this case, the center pixel 2, 3) are arranged one pixel (1, 4) in the up and down direction, and the left and right unmatching between the playback image and CCD pixels through the comparison of the center pixel (2, 3) and up and down pixels (1, 4) It can be determined.

In addition, the mismatch detecting unit 140 has a sum of light amounts corresponding to two center pixels in the light amount information provided from the first and second alignment mark extracting units 140 and 142. When the light quantity information corresponding to one pixel is the same, it is determined that the top, bottom, left, and right match between the CCD pixels and the reproduced image is matched, and the light amount of one central pixel provided by the first and second alignment mark extracting units 140 and 142. If the information has a value larger than the light quantity information of the left (up) (or right) side pixel of the center pixel, the information is determined to be asymmetric up and down (or left and right), and the misalignment compensation value is calculated using the light quantity difference. do.

Here, the asymmetry correction device further includes a control block 146 that receives the misalignment compensation value from the mismatch detection unit 144 and aligns the CCD 128 array by moving it up, down, left, and right based on the misalignment compensation value.

In this manner, the mismatch detection unit 144 uses the x-axis and y-axis alignment marks detected by the first and second alignment mark detection units 140 and 142 to determine the ratio of the vertical direction between the CCD pixel and the playback image. It determines whether there is a match, and calculates and provides a misalignment correction value corresponding to the mismatch to the control block 146, and the control block 146 supplies the CCD 128 array based on the misalignment correction value. It moves up and down to match the CCD pixel with the reproduced image.

As such, when the matching between the CCD pixels and the reproduced image is completed, the holographic digital data system reproduces the data stored in the storage medium 126.

According to the present invention, when the data is recorded on the storage medium 126, an align mark having all on values is recorded in the peripheral x-axis and y-axis directions of the data image and then reproduced by the diamond-shaped detector during alignment. Can be extracted and judged and corrected for matching in up, down, left and right directions between the CCD pixel and the reproduced image.

As described above, the present invention records holographic digital data in which an alignment mark is inserted into a storage medium using a spatial light modulator, and detects an alignment mark in a reproduced image during playback, after detecting it with a diamond-shaped detector. By detecting the misalignment between the pixel of the in mark and the CCD pixel, mismatching of the reproduced image and the CCD pixel can be measured more accurately.

On the other hand, the present invention is not limited to the above-described embodiment, various modifications are possible by those skilled in the art within the spirit and scope of the present invention described in the claims to be described later.

Claims (4)

The hologram data recorded on the storage medium as an interference pattern by interfering the signal light and the reference light modulated by the signal light with the x and y-axis alignment marks composed of a data image, an edge with all off values, and three pixels with all on values. A device for reproducing and compensating for mismatching between a reproduced image and CCD pixels, Four pixels are arranged in a diamond shape, and when data is reproduced, the reproduction light output from the pixels corresponding to the x-axis alignment mark is received by the four pixels, and the light quantity information of the four pixels is extracted. A first align mark extracting unit provided, Four pixels are arranged in a diamond shape, and when the data is reproduced, the reproduction light output from the pixels corresponding to the y-axis alignment mark is received by the four pixels, and the light quantity information of the four pixels is extracted. A second alignment mark extracting unit provided by It is determined whether there is no vertical mismatch between the reproduced image and the CCD pixels by comparing light quantity information of four pixels provided by the first alignment mark extracting unit, and the four pixels provided by the second alignment mark extracting unit. Mimatch detection unit for determining whether the left and right mismatch between the reproduction image and the CCD pixels by comparing the amount of light information Mimatch correction device of the holographic digital data system comprising a. The method of claim 1, The mismatch detection unit may further include a light amount corresponding to one pixel to the left and right (or up and down) of the center pixel in which the sum of the light amounts corresponding to the two central pixels in the light quantity information provided by the first and second alignment mark extracting units is equal. And mismatching correction apparatus of a holographic digital data system, characterized in that if the information is the same, it is determined that the CCD pixels are matched up, down, left and right. The method of claim 1, The mismatch detection section may include light quantity information of one center pixel provided by the first and second alignment mark extracting units rather than light quantity information of a left (up) (or right) side pixel of the center pixel. And determining a misalignment compensation value using the difference in the amount of light, and calculating a misalignment compensation value using the difference in the amount of light. The method of claim 3, wherein The mismatch correcting apparatus of the holographic digital data system further comprises a control block for aligning the CCD by moving the CCD up, down, left, and right based on the misalignment compensation value.

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