KR100738975B1 - Method for sampling optical information, apparatus for sampling optical information and method for processing optical information - Google Patents

Abstract

An optical information sampling method, an optical information sampling device, and an optical information processing method are provided to sample data by selecting a more appropriate sampling process according to a degree of mis-alignment occurring when optical information is detected, thereby remarkably improving reliability on reproduced optical information. Detection images of at least one of pre-sampling data inserted into a data page are detected from oversampling detection images(S1). The detected images are individually sampled through plural sampling processes, and a sampling process relatively having the smallest error is decided on(S2,S3). Data of the oversampling detection images are sampled by using the decided sampling process(S4).

Description

Optical information sampling method, optical information sampling apparatus and optical information processing method {Method for Sampling Optical Information, Apparatus for Sampling Optical Information and Method for Processing Optical Information}

1 is a block diagram showing the configuration of an optical information processing system equipped with an optical information sampling apparatus according to a preferred embodiment of the present invention.

FIG. 2 is an exemplary diagram showing an image of a data page provided by the spatial light modulator shown in FIG. 1.

FIG. 3 is a block diagram showing the configuration of an optical information sampling apparatus according to a preferred embodiment of the present invention shown in FIG.

4A and 4B are graphs illustrating bit error rate (BER) and signal-to-noise ratio (SNR) according to misalignment when sampling is performed using the first sampling process module shown in FIG. 3.

5A and 5B are graphs illustrating bit error rates and signal-to-noise ratios according to misalignments when sampling is performed using the second sampling process module.

6 is a flowchart illustrating a flow of an optical information sampling method according to a preferred embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

100: optical information processing system

150: optical information storage medium

160: optical information detector

200: optical information sampling device

202: control module

210: first sampling process module

220: second sampling process module

240: memory

The present invention relates to an optical information sampling method, an optical information sampling apparatus, and an optical information processing method. More particularly, the present invention relates to a method for sampling data by selecting a more appropriate sampling process according to a degree of misalignment occurring when optical information is detected. And an optical information sampling apparatus and an optical information processing method related thereto.

In recent years, as the demand for a next generation storage system having a large capacity is increased, an optical low processing system using holography, that is, a holographic optical information processing system, has attracted attention.

The holographic optical information processing system is a system conceived from the principle that when two lights having different incidence angles intersect at a predetermined position of a light sensitive photosensitive medium, an interference pattern generated by the interference of the two lights is recorded in the photosensitive medium. .

Such a holographic optical information processing system processes digital data in predetermined page units. Such data in page units is commonly referred to as data pages. That is, the holographic optical information processing system processes information in units of data pages.

As an example of the operation, the holographic optical information processing system encodes input data in units of data pages, generates an image of a two-dimensional data page by mapping each encoded binary data to each pixel, and then applies it to the signal light. Project the light onto an optical information storage medium. Such optical modulation may be performed through a spatial light modulator (SLM). Then, a reference light irradiated from an angle different from the signal light is incident on the optical information storage medium. The signal light and the reference light interfere with each other in the optical information storage medium, so that an image of the data page contained in the signal light is recorded in the optical information storage medium in the form of an interference pattern.

The image of the data page recorded in the form of the interference pattern as described above can be reproduced by irradiating the interference pattern with the reference light. At this time, the image of the reproduced data page is detected through a light receiving array element such as a complementary metal-oxide semiconductor (CMOS) or a charge coupled device (CCD), and then reproduced as original data through a series of signal processing and decoding processes.

However, at the time of reproducing the image of the data page described above, the position of the reproduced image formed on the light receiving array is changed due to the shrinkage or rotation of the optical information storage medium, and as a result, misalignment. This may cause pixels of the data page image (hereinafter, abbreviated as data pixels) and pixels of the light receiving array element (hereinafter, abbreviated as detection pixels) to be mismatched with each other. Therefore, when the image of the data page is detected by matching the data pixel and the detection pixel in a 1: 1 manner, the image of the detected data page may be severely degraded to obtain accurate information.

Therefore, in order to replace the 1: 1 pixel matching method having such disadvantages, various oversampling methods such as 1: 3 oversampling, 1: 2 oversampling, 1: 1.5 oversampling, etc. It is started.

The oversampling method is a method of detecting an image of a data page using a larger number of detection pixels at a predetermined ratio than a data pixel, and then sampling appropriate data from the oversampling detection image.

For example, in the case of the 1: 2 oversampling method, an optical system is configured such that four (2 × 2) detection pixels per data pixel correspond to each other to detect an image of a data page, and then on the oversampling detection image. The value of the detection pixels is sampled through an appropriate sampling process. In this case, the sampling process may include sampling only values of detection pixels that detect an image of the most accurate data pixel on the detection image, or adding and averaging the values of four detection pixels corresponding to each data pixel. Various sampling processes may be used.

However, in the prior art, any one of these sampling processes was adopted before the configuration of the system, which was determined to be the most appropriate through the experiment, and then the system was used. That is, conventionally, only one sampling process is used when sampling data in the detected image.

However, since the misalignment generated when the image of the data page is detected is slightly different for each detected image, a bit error rate (BER) may be high when only a uniform sampling process is used as in the related art. This is because the sampling errors may vary in bit error rate according to the degree of misalignment, and even a particular sampling process determined to be appropriate is not effective for all detected images.

Therefore, the conventional sampling method in oversampling has a problem in that there is a limit in accuracy of detected data.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and provides an optical information sampling method that enables sampling of data by selecting an appropriate sampling process according to the degree of misalignment when data sampling of an image detected by oversampling. This is the first object of the present invention.

Further, a second object of the present invention is to provide an optical information sampling apparatus capable of realizing the above-described optical information sampling method.

It is also a third object of the present invention to provide an optical information processing method for inserting presampling data at a predetermined position of a data page so that an appropriate sampling process can be selected at the time of sampling.

The optical information sampling method according to the present invention for achieving the first object of the present invention, a method for sampling data from the oversampling detection image detected by the oversampling optical system image of the data page stored in the optical information storage medium Detecting a detection image of at least one presampling data inserted into the data page from the oversampling detection image; Sampling each of the detected images of the detected presampling data through a plurality of sampling processes to determine a sampling process having the least error; And sampling data of the oversampling detection image using the determined sampling process.

In this case, the sampling and determining may include: sampling a detected image of the presampling data through the plurality of sampling processes, respectively, to obtain a plurality of presampling data; And comparing each of the acquired presampling data with prestored presampling data to determine a sampling process having the least error. In this case, the determining step calculates any one of a bit error rate and a signal-to-noise ratio of each obtained presampling data, and determines the sampling process with the least error.

The plurality of sampling processes include: a first sampling process for sampling only a value of a detection pixel that accurately detects an image of a data pixel; And a second sampling process of performing sampling by adding values detected by the plurality of detection pixels corresponding to each data pixel. In the detecting of the detected image of the presampling data, the detected image of the presampling data existing on the oversampling detection image is detected by using the position information of the presampling data stored in advance.

On the other hand, the optical information sampling apparatus according to the present invention for achieving the second object of the present invention, the optical information linked to the optical information detector for detecting an image of the data page stored in the optical information storage medium through the oversampling optical system A sampling apparatus, comprising: a plurality of sampling process modules for sampling an oversampling detection image detected by the optical information detector through a unique sampling process; And detecting a detection image of at least one presampling data inserted into the data page from the oversampling detection image, and controlling the plurality of sampling process modules to sample the detected images of the detected presampling data, respectively. It includes a control module that determines the sampling process module having the least error. In this case, the control module controls the determined sampling process module to sample the oversampling detection image.

The optical information sampling apparatus may further include a memory in which insertion information of at least one presampling data inserted into the data page is stored in advance. In this case, the control module detects a detection image of the presampling data on the oversampling detection image using the insertion information of the presampling data stored in the memory.

The control module determines the sampling process module that performed the sampling process with less error by comparing the sampling results performed by the plurality of sampling process modules with the insertion information of the presampling data stored in the memory. In addition, the control module calculates at least one of a bit error rate and a signal-to-noise ratio of a sampling result respectively performed by the plurality of sampling process modules.

The plurality of sampling process modules include: a first sampling process module for providing a first sampling process for sampling only a value of a detection pixel that accurately detects an image of a data pixel; And a second sampling process module for providing a second sampling process for performing sampling by adding values detected by the plurality of detection pixels corresponding to each data pixel.

On the other hand, the optical information processing method according to the present invention for achieving the third object of the present invention comprises the steps of inserting at least one presampling data in the data page and storing in the optical information storage medium; And a sampling process of detecting the image of the stored data page through an oversampling optical system, sampling the detected image of the inserted presampling data from the detected image through a plurality of sampling processes, and then sampling the least error. Sampling the detected image using.

The detecting and sampling step may include detecting an image of the stored data page through the oversampling optical system; Detecting a detected image of presampling data inserted into the data page from the detected image; Sampling the detected images of the detected presampling data with a plurality of sampling processes, respectively, to determine a sampling process with relatively few errors; And sampling the oversampling detection image of the data page using the determined sampling process.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

1 is a block diagram showing the configuration of an optical information processing system equipped with an optical information sampling apparatus according to a preferred embodiment of the present invention.

Referring to FIG. 1, the optical information processing system 100 includes a light source 110, a light splitter 120, a first shutter 131, a second shutter 132, and a first reflector ( 133, a second reflector 134, a data encoding unit 180, a spatial light modulator (SLM) 140, an optical information storage medium 150, an actuator 170, The optical information detector 160, the optical information sampling device 200, and the data decoding unit 190 are included.

The light irradiated from the light source 110 is separated into a reference beam and a signal beam through the light separator 120. In this case, the reference light is reflected by the first reflector 133 and is incident on the optical information storage medium 150.

On the other hand, the signal light is reflected by the second reflector 134 is incident to the spatial light modulator 140. At this time, the spatial light modulator 140 receives binary data, that is, data page information, in units of encoded pages provided by the data encoding unit 180.

The data page information includes insertion information of presampling data. In this case, the insertion information of the pre-sampling data may include information such as the position and contents of the presampling data to be inserted into the data page imaged in two dimensions.

The spatial light modulator 140 optically modulates the data page information input from the data encoding unit 180 to generate a two-dimensional imaged data page, and projects the reflected optical data onto the incident signal light. Incident.

At least one presampling data is inserted into the data page. The insertion information of the presampling data is also stored in the optical information sampling device 200. That is, the position and content of the presampling data are information previously recognized by the optical information sampling device 200 as well. The contents related to this data page will be described later with reference to FIG. 2.

On the other hand, when the reference light and the signal light is incident on the optical information storage medium 150, in the optical information storage medium 150, the mineral oil of the internal kinetic charge according to the intensity of the interference pattern generated by the interference between the incident reference light and the signal light A light induced generation of mobile charge occurs and the interference pattern is recorded. This may be a holographic interference fringe. The actuator 170 may adjust the angle of incidence of the reference beam by adjusting the angle of the first reflector 133, and may overwrite and record the multilayer data page through the angle multiplexing on the optical information storage medium 150.

In order to reproduce the recorded data, only the reference light may be irradiated to the optical information storage medium 150. That is, during reproduction, the first shutter 131 passes the reference light separated by the optical separator 120, and the second shutter 132 blocks the separated signal light.

At this time, the reference light irradiated to the first reflector 133 through the first shutter 131 is diffracted by the interference fringe recorded on the optical information storage medium 150 to reproduce an image of the data page. The image of the reproduced data page is detected by the optical information detector 160 through a predetermined oversampling optical system and then sampled by the optical information sampling apparatus 200. Subsequently, the sampled data is decoded by the data decoding unit 190 to restore original data.

FIG. 2 is an exemplary diagram showing an image of a data page provided by the spatial light modulator shown in FIG. 1.

As shown in FIG. 2, the data page 10 includes a data area 14 including data information and a presampling area 12 into which presampling data is inserted. At this time, the presampling data is reference data for selecting an appropriate sampling process at the time of sampling.

In addition, in FIG. 2, one presampling region 12 is positioned outside the data region, but a plurality of presampling regions may exist and may be located in the data region. Of course, a plurality may be located in the data area. That is, a plurality of presampling data may be inserted at a designated position inside or outside the data area.

3 is a block diagram showing the configuration of an optical information sampling apparatus 200 according to a preferred embodiment of the present invention shown in FIG.

As shown in FIG. 3, the optical information sampling device 200 is linked with the optical information detector 160. In this case, the optical information detector 160 detects the reproduced image of the data page reproduced by the reference light in the optical information storage medium 150.

Preferably, the optical information detector 160 has an oversampling optics. For example, the optical information detector 160 may have a pixel arrangement capable of 1: 3 oversampling, 1: 2 oversampling, and 1: 1.5 oversampling image detection. In the present embodiment, it is assumed that the optical information detector 160 has a 1: 2 oversampling optical system. That is, one data pixel of the reproduced data page may match four detection pixels (2 × 2).

The optical information sampling apparatus 200 includes a first sampling process module 210, a second sampling process module 220, a memory 240, and a control module 202.

The first sampling process module 210 samples the oversampling detection image detected by the optical information detector 160 according to the first sampling process. In this case, the first sampling process is a sampling process of sampling only a value of one detection pixel that most accurately detects an image of the data pixel among four detection pixels for detecting one data pixel on a 1: 2 oversampling detection image. to be. That is, this may mean a sampling process of sampling only values of detection pixels that accurately detect an image of a data pixel.

4A and 4B are graphs illustrating bit error rates and signal-to-noise ratios (SNRs) according to misalignments when sampling is performed using the first sampling process module 210. 4A and 4B, the Y axis represents bit error rate and signal to noise ratio, respectively, and the X axis represents the degree of misalignment in one data pixel. That is, the total misalignment degree indicated by the X-axis coordinates is 1 pixel.

As shown in FIG. 4A, according to the first sampling process performed by the first sampling process module 210, a misalignment occurs about half a pixel than when a slight misalignment occurs (0.5-Misalign, X In the middle of the axis), the bit error rate is the lowest.

In addition, referring to the graph shown in FIG. 4B, it can be seen that the signal-to-noise ratio is the best when the misalignment occurs about half a pixel in the first sampling process.

Accordingly, it is found that the first sampling process is advantageous when the image of the data pixel is intensively detected in one detection pixel out of four detection pixels due to relatively larger misalignment than when a little misalignment occurs. Can be.

Meanwhile, the second sampling process module 220 samples the oversampling detection image detected by the optical information detector 160 according to the second sampling process. In this case, the second sampling process is a sampling process in which the detection values of four detection pixels for detecting one data pixel on a 1: 2 oversampling detection image are added, and then sampled by reflecting the average value. That is, it may mean a sampling process of reconstructing one data by adding detection pixels corresponding to the data pixels.

5A and 5B are graphs illustrating bit error rates and signal-to-noise ratios according to misalignments when sampling is performed by using the second sampling process module 220. 5A and 5B, the Y axis represents bit error rate and signal to noise ratio, respectively, and the X axis represents the degree of misalignment occurring within one data pixel.

As shown in FIG. 5A, according to the second sampling process provided by the second sampling process module 220, the bit error rate is lower when a few misalignments occur than when a large misalignment occurs. Able to know.

In addition, referring to the graph illustrated in FIG. 5B, in the second sampling process, the signal-to-noise ratio is the best at perfect alignment, and the signal-to-noise ratio is the worst when the misalignment occurs about half a pixel.

Therefore, it can be seen that the second sampling process is an advantageous sampling process when a relatively small misalignment occurs rather than when a large misalignment occurs.

Meanwhile, the memory 240 stores insertion information of presampling data. The insertion information of the presampling data is information in which the position where the presampling data is inserted, the content of insertion of the presampling data, and the like are defined. Insertion information of the presampling data may be provided to the control module 202 upon selection of a sampling process for sampling of the detected oversampling image.

The control module 202 controls the first sampling process module 210 and the second sampling process module 220 so that a predetermined position (presampling data) on the oversampling detection image detected by the optical information detector 160 A sampling process module 210 having a relatively low error by sampling the inserted position) and acquiring the presampling data, and comparing the obtained two presampling data with the insertion information of the presampling data stored in the memory 240, respectively. 220 to sample the data of the oversampling detection image.

That is, the control module 202 detects the detection image of the presampling data on the oversampling detection image of the data page, and samples the detected image through the first sampling process module 210 and the second sampling process module 220. Subsequently, the control unit is configured to sample the data by selecting the one having the smaller error among the sampling data performed by the first sampling process module 210 and the sampling data performed by the second sampling process module 220.

In this case, the control module 202 may determine a sampling process having fewer errors by comparing bit error rates or signal-to-noise ratios of the presampling data detected by the two sampling processes 210 and 220.

Therefore, as described above with reference to FIGS. 4A, 4B, 5A, and 5B, when a slight misalignment occurs, a relatively more efficient second sampling process module 220 may be selected, and when the misalignment is large, The more efficient first sampling process module 210 will be selected.

6 is a flowchart illustrating a flow of an optical information sampling method according to an exemplary embodiment of the present invention, which may be easily performed based on the optical information sampling apparatus 200 described above.

Referring to FIG. 6, first, when an oversampling image of a data page stored in the optical information storage medium 150 is detected by the optical information detector 160, the optical information sampling apparatus 200 performs an operation on the detected oversampling detection image. A detection image of the presampling data inserted into the data page is detected (step: S1). This can be detected by searching for location information of the presampling area stored in the memory 240.

Subsequently, the optical information sampling apparatus 200 samples each of the presampling detection regions by using the first sampling process and the second sampling process (step: S2). Therefore, the presampling data sampled by the first sampling process and the presampling data sampled by the second sampling process can be obtained.

In this case, the case of two sampling processes will be described. However, the number of sampling processes may be two or more. However, considering the complexity of the system, two to four sampling processes are appropriate.

When the presampling data obtained by the two sampling processes is acquired, the optical information sampling apparatus 200 determines a sampling process in which the presampling data having less error is sampled among the two presampling data obtained (step: S3).

In this case, the optical information sampling apparatus 200 may determine presampling data having less error by obtaining bit error rates or signal-to-noise ratios of the two presampling data with reference to the insertion information of the presampling data previously stored. Sampling of the presampling data may be performed through simple sampling, diagonal sampling, or the like.

Subsequently, the optical information sampling apparatus 200 samples the remaining data portion of the oversampling detection image by using a sampling process with a small error in the determination result (step: S4). That is, the detected data detection area is sampled on the oversampling detection image corresponding to the data area of the source data page. Therefore, sampling of the optical information by the sampling process with few errors is possible.

As described above, the present invention does not uniformly use only one sampling process when sampling a plurality of optical information, but can select and perform a sampling process with less error according to the degree of misalignment of each optical information. have. Therefore, reliable data can be reproduced.

On the other hand, by applying the above-described embodiment, by inserting a plurality of presampling data into the data area, and sampling each presampling data by a plurality of sampling processes to determine the degree of error, each part of the data area is different You can also use a sampling process. That is, since the misalignment may be different on one detection image, such a method may be more efficient.

Further, when detecting a plurality of optical information stored in the optical information storage medium 150, the sampling process selected at the time of sampling the first oversampling detection image is continuously used at the time of sampling the next oversampling detection image, or specified oversampling. The sampling process used for sampling the detected image may then be used at the time of sampling the oversampling detected image. This is because adjacent optical information often has a similar degree of misalignment. In this case, the number of sampling of the presampling data may be reduced.

Although the present invention has been described above with reference to its preferred embodiments, those skilled in the art will variously modify the present invention without departing from the spirit and scope of the invention as set forth in the claims below. And can be practiced with modification. Accordingly, modifications to future embodiments of the present invention will not depart from the technology of the present invention.

As described above, according to the present invention, a more appropriate sampling process can be selected according to the degree of misalignment generated at the time of detecting the optical information to sample the data. Therefore, the accuracy of the reproduced data can be much higher than in the related art, and thus the reliability of the reproduced optical information can be greatly improved.

Claims (14)

A method for sampling data from an oversampling detection image of detecting an image of a data page stored in an optical information storage medium through an oversampling optical system, Detecting a detection image of at least one presampling data inserted into the data page from the oversampling detection image; A discriminating step of sampling the detected images of the detected presampling data through a plurality of sampling processes, respectively, to determine a sampling process having the least error; And And sampling the data of the oversampling detection image using the determined sampling process. The method of claim 1, wherein the determining step, Sampling each of the detected images of the presampling data through the plurality of sampling processes to obtain a plurality of presampling data; And And comparing each of the acquired presampling data with prestored presampling data to determine a sampling process having the least error. 3. The method of claim 2, wherein the step of comparing the acquired presampling data with prestored presampling data to determine a sampling process having the least error, wherein the bit error rate of each of the acquired presampling data and And calculating at least one of a signal-to-noise ratio to determine the sampling process with the least error. The method of claim 1, wherein the plurality of sampling processes, A first sampling process for sampling only a value of a detection pixel that accurately detects an image of the data pixel; And And a second sampling process of adding the values detected by the plurality of detection pixels corresponding to each data pixel, and performing sampling by reflecting the average value. The optical information sampling method of claim 1, wherein a plurality of the presampling data is inserted into a data area of the data page. The method of claim 1, wherein the detecting of the detected image of the presampling data comprises detecting the detected image of the presampling data existing on the oversampling detection image by using the position information of the presampling data stored in advance. Optical information sampling method. An optical information sampling device linked to an optical information detector for detecting an image of a data page stored in an optical information storage medium through an oversampling optical system, A plurality of sampling process modules for sampling the oversampling detection image detected by the optical information detector through a unique sampling process; And Detecting a detection image of at least one presampling data inserted into the data page from the oversampling detection image, and controlling the plurality of sampling process modules to sample the detected images of the detected presampling data, respectively. And a control module for determining a sampling process module having the least error. 8. The optical information sampling device of claim 7, wherein the control module controls the determined sampling process module to sample the oversampling detection image. 8. The apparatus of claim 7, further comprising a memory in which insertion information of at least one presampling data inserted into the data page is stored in advance. And the control module detects a detection image of the presampling data on the oversampling detection image by using the insertion information of the presampling data stored in the memory. The sampling process according to claim 9, wherein the control module performs a sampling process with less error by comparing sampling results respectively performed by the plurality of sampling process modules with insertion information of presampling data stored in the memory. Optical information sampling device characterized in that it determines the module. The optical information sampling apparatus of claim 10, wherein the control module calculates at least one of a bit error rate and a signal-to-noise ratio of a sampling result respectively performed by the plurality of sampling process modules. The method of claim 7, wherein the plurality of sampling process modules, A first sampling process module for providing a first sampling process for sampling only a value of a detection pixel that accurately detects an image of the data pixel; And And a second sampling process module for providing a second sampling process for performing sampling by adding the values detected by the plurality of detection pixels corresponding to each data pixel and reflecting the average value thereof. Sampling device. Inserting at least one presampling data into a data page and storing it in an optical information storage medium; And An image of the stored data page is detected through an oversampling optical system, and the detected image of the inserted presampling data is sampled from the detected image through a plurality of sampling processes, respectively. And a sampling step of sampling the detected image by using the optical information processing method. The method of claim 13, wherein the sampling step, Detecting an image of the stored data page through the oversampling optics; Detecting a detected image of presampling data inserted into the data page from the detected image; Sampling the detected images of the detected presampling data with a plurality of sampling processes, respectively, to determine a sampling process with relatively few errors; And Sampling the oversampling detection image of the data page using the determined sampling process.

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