KR100681901B1 - Optical information detector and structure for arrangement detection pixel for detecting optical information - Google Patents

Abstract

An optical information detector and a detection pixel array structure for detecting optical information are provided to more stably detect optical information of data pixels through optical detection areas properly arrayed within detection pixels, though random pixel non-matching occurs during the detection of the optical information, thus a complex operation is reduced. Detection pixels are arrayed to oversample optical information of a data page in 1:n(n is a non-integer larger than 1) ratio. Optical detection areas(P1-P9) of smaller size than the detection pixels are disposed within the detection pixels, and the detection pixels detect the optical information of the data page through the optical detection areas(P1-P9). 1 data pixel of the data page is mapped with an n x n detection pixel.

Description

Optical information detector and detection pixel arrangement for optical information detection {OPTICAL INFORMATION DETECTOR AND STRUCTURE FOR ARRANGEMENT DETECTION PIXEL FOR DETECTING OPTICAL INFORMATION}

1A and 1B are exemplary diagrams illustrating a configuration of a data pixel and a detection pixel for explaining an image detection concept of a data page using 1: 1.5 oversampling.

FIG. 2 is an exemplary diagram illustrating a case where pixel mismatching does not occur when an image of a data page is detected through 1: 1.5 oversampling.

FIG. 3 is an exemplary diagram illustrating a case where pixel mismatching occurs when detecting an image of a data page through 1: 1.5 oversampling.

4 is a block diagram showing the configuration of an optical information reproducing apparatus.

Fig. 5 is an exemplary view showing the arrangement of a detection pixel and a light detection region of the optical information detector according to the first preferred embodiment of the present invention.

6A and 6B are exemplary diagrams for describing a concept of detecting data in a pixel mismatching state using a detection pixel structure having the light detection region illustrated in FIG. 5.

FIG. 7 is an exemplary diagram showing the structure of a detection pixel and a light detection area of the optical information detector according to the second preferred embodiment of the present invention.

8A and 8B are exemplary diagrams for describing a concept of detecting data in a pixel mismatching state using a detection pixel structure having the light detection region illustrated in FIG. 7.

9 is an exemplary diagram showing the structure of a detection pixel and a light detection area of the optical information detector according to the third preferred embodiment of the present invention.

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

10: light irradiation part

20: optical information storage medium

30: signal processing unit

40: decoding unit

100: optical information detector

P1, P2, P3, P4, P5, P6, P7, P8, P9: light detection region

The present invention relates to an optical information detector and a detection pixel arrangement structure for detecting optical information. More particularly, the optical information can stably detect optical information even if any pixel mismatch occurs during optical information detection. A detector and a structure of a light detection area of a detection pixel for detecting light information.

In general, an optical information processing system using holography, that is, a holographic optical information processing system, irradiates a signal light containing data and a reference light provided from an angle different from the signal light to a predetermined position of the optical information storage medium. And cross each other, the interference pattern is recorded on the optical information storage medium. In addition, when the stored information is reproduced, the reference light is irradiated to the stored interference pattern, and the original data is restored by using diffraction generated by the interference pattern.

The holographic optical information processing system can store data at the same position of the optical information storage medium by using various multiplexing techniques, and can superimpose and reproduce the superimposed stored data. Can be implemented. In this case, the multiplexing technique includes angle multiplexing, wavelength multiplexing, phase code multiplexing, and the like.

On the other hand, the holographic optical information processing system processes digital data in predetermined page units, and this page unit data is called a data page. That is, the holographic optical information processing system processes data in units of data pages.

For example, 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 projects it onto a signal light. Investigate with optical information storage media. Such optical modulation may be performed through a spatial light modulator (SLM).

In this case, 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.

By the above process, the image of the data page recorded on the optical information storage medium can be reproduced by irradiating the interference pattern with reference light. The image of the reproduced data page may be detected through a light receiving array element, for example, a complementary metal-oxide semiconductor (CMOS) or a charge coupled device (CCD). At this time, the detected image of the data page is reproduced as original data through a predetermined signal processing and decoding process.

Meanwhile, when detecting an image of a data page using a light receiving array element, various sampling techniques such as 1: 1 pixel matching, 1: 3 oversampling, and 1: 2 oversampling , 1: 1.5 oversampling, or the like can be used.

The 1: 1 pixel matching technique is a method of 1: 1 matching a pixel of a reproduced data page image (hereinafter, abbreviated as data pixel) and a pixel of a light receiving array element (hereinafter, abbreviated as detection pixel). In this 1: 1 pixel matching technique, since one data pixel directly corresponds to one detection pixel, the storage density at the time of image detection is high.

However, when an image of a data page is actually reproduced, the position of the reproduction image formed in the light receiving array is changed due to the shrinkage or rotation of the optical information storage medium, and as a result, misalignment occurs. As a result, the data pixel and the light receiving pixel are mismatched with each other.

However, the 1: 1 pixel matching technique causes severe degradation of an image of the data page detected by the quenching array element when mismatching of 1/2 or more of the data pixel size occurs. Therefore, if the pixel mismatching is severe, accurate information cannot be obtained.

The 1: 3 oversampling method is a method of detecting one data pixel as nine (3 × 3) detection pixels. In the case of the 1: 3 oversampling method, even if mismatching between the data pixel and the detection pixel occurs arbitrarily, the detection pixel located at the center of the nine detection pixels can detect the light of the data pixel. Therefore, even if the image of the reproduced data page exists at any position of the light receiving array element, reliable data can be obtained from the image detected by the center detection pixel.

However, this 1: 3 oversampling method requires too many detection pixels to detect one data pixel at the time of image detection, so the storage density is too low. For example, in the case of using a light receiving arrangement consisting of 1200 × 1200 detection pixels, one data page should include only 400 × 400 data. Therefore, the stability of the system can be secured, but there is a serious disadvantage of lowering the storage capacity, which is the greatest strength of the holographic memory.

The 1: 2 oversampling method is a method of detecting one data pixel as four (2 × 2) detection pixels. Similar to the 1: 3 oversampling method described above, one of the four detection pixels can detect the light of the data pixel and thus obtain reliable data. However, this 1: 2 oversampling method has a disadvantage that the information storage density is only 25% compared to the pixel matching method.

As such, the conventional pixel matching method has a good storage density, but has a disadvantage of being too vulnerable to misalignment between pixels. In the conventional 1: 3 oversampling method and the 1: 2 oversampling method, the data detection reliability is high but the storage density is high. There is a problem too low. Therefore, there is a demand for a technique capable of satisfying a high storage density while ensuring the reliability of data detection.

SUMMARY OF THE INVENTION The present invention has been made in view of this background, and it is a first object of the present invention to provide an optical information detector that can stably detect optical information even if any pixel mismatch occurs during optical information detection.

It is also a second object of the present invention to provide a detection pixel arrangement structure for detecting optical information that can be applied to the optical information detector.

The optical information detector according to the present invention for achieving the first object of the present invention includes a detection pixel arranged to oversample 1: n (n is a non-integer greater than 1) of optical information of a data page. And a light detection area having a smaller size than the detection pixel in the detection pixel, wherein the detection pixel detects light information of the data page through the light detection area. One data pixel of the data page may be mapped to n × n of the detection pixels.

The horizontal width of the light detection area may be smaller than the horizontal width of the detection pixel. The horizontal width of the light detection area may be about 1/2 of the horizontal width of the detection pixel. In addition, the vertical width of the light detection area may be smaller than the vertical width of the detection pixel. The vertical width of the light detection area may be about 1/2 of the vertical width of the detection pixel.

On the other hand, the optical information detector for achieving the first object of the present invention described above, in the optical information detector for detecting the optical information of the plurality of data pixels, n × n pieces per one data pixel (n is 1 And a plurality of detection pixels arranged at a ratio of greater non-integer), wherein the detection pixels have a size smaller than that of the detection pixels, and have a light detection area therein for detecting light information of the data pixels. You may.

The horizontal width or vertical width of the light detection area may be smaller than the horizontal width or vertical width of the detection pixel, respectively. The optical information areas provided in the plurality of detection pixels, respectively, may be disposed at the same position in the detection pixel. Preferably, the optical information areas provided in the plurality of detection pixels have the same shape.

On the other hand, the detection pixel arrangement structure for detecting the optical information according to the present invention for achieving the second object of the present invention described above is one of the detection pixel arrangement structure for detecting the optical information of the plurality of data pixels. Detection pixels are arranged at a rate of n × n (n is a non-integer greater than 1) per data pixel, and the detection pixels are light of the data pixels through an internal light detection area having a size smaller than the detection pixels. It is characterized by detecting the information.

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. In addition, in describing the preferred embodiment of the present invention illustrated in the drawings, specific technical terms are used for clarity of content. However, it is to be understood that the invention is not limited to these specific selected terms, and that each specific term includes all technical synonyms that operate in a similar manner to achieve a similar purpose.

1A and 1B are exemplary diagrams illustrating a configuration of a data pixel and a detection pixel for explaining an image detection concept of a data page using 1: 1.5 oversampling.

1: 1.5 oversampling is a method of constructing an optical system such that one data pixel of a source data page is mapped to 1.5 × 1.5 detection pixels, and reconstructing the source data page by sampling an image detected from each detection pixel. Means. Therefore, in the 1: 1.5 oversampling, the 2x2 data pixel corresponds to the 3x3 detection pixel.

Referring to FIG. 1A, a 2x2 data pixel block consists of four data pixels, namely D1, D2, D3, and D4. In this case, the image of each data pixel may mean binarized data information, that is, binary information.

The data information of the 2x2 data pixel block may be detected by the 3x3 detection pixel block illustrated in FIG. 1B. In this case, as illustrated in FIG. 1B, the 3 × 3 detection pixel block may include nine detection pixels, that is, C1, C2, C3, C4, C5, C6, C7, C8, and C9.

FIG. 2 is an exemplary diagram illustrating a case where pixel mismatching does not occur when an image of a data page is detected through 1: 1.5 oversampling. In the description of FIG. 2, a large grid represents a data pixel and a small grid represents a detection pixel. In addition, the sign of each data pixel and the detection pixel will use the sign of FIGS. 1A and 1B described above.

Referring to FIG. 2, it can be seen that 2 × 2 data pixels and 3 × 3 detection pixels are exactly matched. In this case, the images of the four data pixels D1, D2, D3 and D4 can be accurately detected by the detection pixels C1, C3, C7 and C9.

In this case, the detection pixel C2 may be a meaningless value because it detects information in which the image of D1 and the image of D2 are mixed. Similarly, since the detection information of C4, C5, C6, and C8 is information in which images of a plurality of data pixels are mixed, the detection information of C4, C5, C6, and C8 may be meaningless values in image detection of data pixels.

3 is an exemplary diagram illustrating a case where pixel mismatching occurs when an image of a data page is detected through 1: 1.5 oversampling.

Referring to FIG. 3, the information of the data pixel D1 may be accurately detected by the detection pixel C1. However, the information of the data pixels D2, D3 and D4 cannot be detected by the information of the direct detection pixels.

In this case, the information of the data pixels D2, D3, and D4 should be calculated through a sampling process through a complicated calculation. However, in the present invention, it is possible to stably detect an image of a data pixel by setting various sizes of the light detection region of the detection pixel.

4 is a block diagram showing the configuration of an optical information reproducing apparatus.

Referring to FIG. 4, the optical information reproducing apparatus may include a light irradiator 10 that generates light such as a laser beam and irradiates the optical information storage medium 20. The light irradiated by the light irradiator 10 is incident on the optical information storage medium 20 at a predetermined angle. The optical information storage medium 20 stores a plurality of data pages in the form of interference patterns. In this case, the light incident by the light irradiator 10 may be either a reference beam or a phase conjugation reference light for reproducing the interference pattern stored in the optical information storage medium 20.

When light is incident on an interference pattern stored in the optical information storage medium 20, an image of a data page is reproduced by diffraction by the interference pattern. At this time, the image of the reproduced data page is detected by the optical information detector 100 through 1: n (n is a non-integer greater than 1) oversampling. Subsequently, the detected image of the data page is converted into binary data by the signal processor 30, and then decoded by the decoder 40 to be reproduced as original data.

In this case, the 1: n (n is non-integer greater than 1) oversampling means that a detection pixel is disposed such that one data pixel is mapped to n × n detection pixels, and sampled detected light information is used to restore original data. Means that. For example, as described above, in an oversampling of a 1: 1.5 ratio (n = 1.5), since one data pixel corresponds to 1.5 × 1.5 detection pixels, the 2 × 2 data pixels of the light detector 110 It can be mapped to 3 × 3 detection pixels. In another example of 1: 1.33 (n = 1.33) oversampling, since one data pixel corresponds to 1.33 detection pixels, a 3 × 3 data pixel may be mapped to a 4 × 4 detection pixel.

The optical information detector 100 detects an image of a data page stored in the optical information storage medium 20 and reproduced by a reference beam, that is, an image of a source data page through 1: n (n is non-integer) oversampling. It may have a plurality of detection pixels arranged to be able to.

The light detection area having a smaller size than the detection pixel is provided inside the detection pixel. In this case, the light detection area may mean a light receiving area capable of actually detecting an image in the detection pixel.

The detection pixel may be a light receiving element. That is, the optical information detector may include a light receiving arrangement in which a plurality of light receiving elements are arranged. For example, the optical information detector 100 may include a complementary metal-oxide semiconductor (CMOS) or a charge coupled device (CCD).

In this case, the light detection region may be a light receiving region of the light receiving element, and an area other than the light detection region existing in the detection pixel may be a circuit region. Therefore, it can be seen that the detection pixel of the light receiving element has the concept of an arrangement area for arranging the light detection area which is the actual light reception area.

The arrangement of the detection pixels and the light detection regions of the optical information detector 100 will be described in detail with reference to the first, second and third embodiments to be described below.

<Example 1>

In the first embodiment, in the detection pixels arranged to detect an image of a data page through 1: 1.5 oversampling, an optical light can easily detect an image of data pixels even if horizontal pixel mismatch occurs. The arrangement structure of the detection area will be described.

Fig. 5 is an exemplary view showing the arrangement of a detection pixel and a light detection region of the optical information detector according to the first preferred embodiment of the present invention. The grid shown in FIG. 5 represents a detection pixel and a portion indicated by hatching in the detection pixel means a light detection area capable of detecting an actual image.

Referring to FIG. 5, light detection areas P1, P2,..., P8, and P9 having a horizontal width smaller than the horizontal width of the corresponding detection pixel are provided in each detection pixel.

In this case, the horizontal width of the light detection area may have a size 1/2 of the horizontal width of the detection pixel. In this case, if the horizontal width of the detection pixel is defined as X, the horizontal width of the light detection area may be expressed as 0.5X.

In addition, the light detection region may be disposed at a position Δx to the left from the left end of the detection pixel. In this case, Δx may be a value greater than or equal to 0 and greater than or equal to 0.5X. That is, the light detection region can be arranged in a horizontal direction in the detection pixel. However, it is preferable that each light detection area is disposed at the same position in the corresponding detection pixel.

6A and 6B are exemplary diagrams for describing a concept of detecting data in a pixel mismatching state using a detection pixel structure having the light detection region illustrated in FIG. 5, and FIG. 6A is larger than 0 and smaller than Δx. FIG. 6B illustrates a case where a horizontal pixel mismatch of a size occurs, and FIG. 6B illustrates a case where a horizontal pixel mismatch of a size larger than Δx and smaller than 0.5X occurs.

Referring to FIG. 6A, when a horizontal pixel mismatch of a size larger than 0 and smaller than Δx occurs, an image of the data pixel D1 may be detected through the light detection area P1, and the image of the data pixel D2 may be an optical detection area. It is possible to detect through P3, the image of data pixel D3 can be detected through light detection area P7, and the image of data pixel D4 can be detected through light detection area P9. Thus, the images of the data pixels D1, D2, D3 and D4 can all be detected correctly.

Referring to FIG. 6B, when horizontal pixel mismatching of a size larger than Δx and smaller than 0.5X occurs, images of the data pixels D1, D2, D3, and D4 may be detected by the light detection areas P2, P3, P8, and P9. Can be. Therefore, by using the structure of the detection pixel shown in FIG. 5, pixel mismatching that can occur in the horizontal direction can be directly detected without complicated equations. If the pixel mismatch in the horizontal direction is 0.5X or more to the right side, this may be equally detected using the light detection regions of the detection pixels existing on the right side of the detection pixels.

<Example 2>

In the second embodiment, a light for easily detecting an image of data pixels even in a vertical pixel mismatch occurs in a detection pixel arranged to detect an image of a data page through 1: 1.5 oversampling. The arrangement structure of the detection area will be described.

FIG. 7 is an exemplary diagram showing the structure of a detection pixel and a light detection area of the optical information detector according to the second preferred embodiment of the present invention. The grid shown in FIG. 7 represents a detection pixel and a portion indicated by hatching in the detection pixel means a light detection area capable of detecting an actual image.

Referring to FIG. 7, light detection areas P1, P2,..., P8, and P9 having a vertical width smaller than the vertical width of the corresponding detection pixel are provided in each detection pixel.

In this case, the vertical width of the light detection area may have a size 1/2 of the vertical width of the detection pixel. In this case, if the vertical width of the detection pixel is defined as Y, the vertical width of the light detection area may be expressed as 0.5Y.

Further, the light detection region may be disposed at a position spaced apart by Δy from the upper end of the detection pixel. In this case, Δy may be a value greater than or equal to 0 and greater than or equal to 0.5Y. That is, the light detection region can be arranged in a vertical direction in the detection pixel. However, it is preferable that each light detection area is disposed at the same position in the corresponding detection pixel.

8A and 8B are exemplary diagrams for describing a concept of detecting data in a pixel mismatching state using a detection pixel structure having the light detection region illustrated in FIG. 7, and FIG. 8A is larger than 0 and smaller than Δy. FIG. 8B illustrates a case where vertical pixel mismatching of size occurs, and FIG. 8B illustrates a case where vertical pixel mismatching of size larger than Δy and smaller than 0.5Y occurs.

Referring to FIG. 8A, when vertical pixel mismatching of a size larger than 0 and smaller than Δy occurs, images of the data pixels D1, D2, D3, and D4 are detected through the light detection regions P1, P3, P7, and P9, respectively. Can be.

Referring to FIG. 8B, when vertical pixel mismatching of a size larger than Δy and smaller than 0.5Y occurs, images of the data pixels D1, D2, D3, and D4 may be detected by the light detection areas P4, P6, P7, and P9. Can be. Therefore, by using the structure of the detection pixel illustrated in FIG. 7, pixel mismatching that may occur in the vertical direction may be directly detected without complicated formula. If the vertical pixel mismatch occurs more than 0.5Y to the bottom, this may be equally detected using the light detection regions of the detection pixels existing under the detection pixels.

<Example 3>

In the third exemplary embodiment, when image detection of a data page using detection pixels arranged to perform 1: 1.5 oversampling, an image of data pixels is easily detected even if both horizontal and vertical pixel mismatches occur. The arrangement structure of the light detection region to be described will be described.

9 is an exemplary diagram showing the structure of a detection pixel and a light detection area of the optical information detector according to the third preferred embodiment of the present invention. The grid shown in FIG. 9 represents a detection pixel, and the portion indicated by the cross hatched in the detection pixel means a light detection area capable of detecting an actual image.

Referring to FIG. 9, light detection areas P1, P2,..., P8, and P9 having a horizontal width and a vertical width smaller than the horizontal width and vertical width of the corresponding detection pixel are provided in each detection pixel.

In this case, the horizontal width and the vertical width of the light detection area may have a size 1/2 of the horizontal width and the vertical width of the detection pixel, respectively. In this case, if the horizontal width and the vertical width of the detection pixel are defined as X and Y, respectively, the horizontal width and the vertical width of the light detection area may be expressed as 0.5X and 0.5Y, respectively.

In addition, the light detection region may be disposed at a position Δx to the left from the left end of the detection pixel. In this case, Δx may be a value greater than or equal to 0 and greater than or equal to 0.5X. Further, the light detection area may be disposed at a position Δy downward from an upper end of the detection pixel. In this case, Δy may be a value greater than or equal to 0 and greater than or equal to 0.5Y.

That is, the light detection region can be arranged in a horizontal or vertical direction in the detection pixel. However, it is preferable that each light detection area is disposed at the same position in the corresponding detection pixel.

In the structure of the third embodiment, since the structure of the first embodiment and the structure of the second embodiment are both considered, it is possible to easily detect an image of the data pixel even if pixel mismatching in the horizontal and vertical directions occurs. In practice, pixel mismatching is very easy because the pixel mismatching in the horizontal direction and the pixel mismatching in the vertical direction often occur in combination.

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, even if any pixel mismatching occurs in the detection of the optical information, the optical information of the data pixel can be detected more stably through the optical detection region disposed appropriately in the detection pixel.

Therefore, it is possible to reduce the complicated operation required when detecting the optical information, and there is an advantage that the reliable optical information can be detected.

Claims (13)

A detection pixel arranged to oversample the optical information of the datapage 1: n (n is a non-integer greater than 1), And a light detection area having a smaller size than the detection pixel in the detection pixel, wherein the detection pixel detects light information of the data page through the light detection area. The optical information detector of claim 1, wherein one data pixel of the data page is mapped to n × n detection pixels. The optical information detector of claim 1, wherein a horizontal width of the light detection area is smaller than a horizontal width of the detection pixel. The optical information detector of claim 3, wherein the horizontal width of the light detection area is about 1/2 of the horizontal width of the detection pixel. The optical information detector of claim 1, wherein a vertical width of the light detection area is smaller than a vertical width of the detection pixel. The optical information detector of claim 5, wherein the vertical width of the light detection area is about 1/2 of the vertical width of the detection pixel. The optical information detector of claim 1, wherein a horizontal width of the light detection area is smaller than a horizontal width of the detection pixel, and a vertical width of the light detection area is smaller than a vertical width of the detection pixel. An optical information detector for detecting optical information of a plurality of data pixels, A plurality of detection pixels arranged at a rate of n × n (n is a non-integer greater than 1) per one data pixel, And the detection pixel has a size smaller than that of the detection pixel and has a light detection area therein for detecting light information of the data pixel. The optical information detector of claim 8, wherein the horizontal width and the vertical width of the light detection area are at least one smaller than the horizontal width and the vertical width of the detection pixel. 10. The method of claim 9, wherein the horizontal width of the light detection area has a size of about 1/2 of the horizontal width of the detection pixel, and the vertical width of the light detection area is about 1/2 of the vertical width of the detection pixel. Optical information detector, characterized in that having a size of. 10. The optical information detector of claim 8, wherein the optical information regions provided in the plurality of detection pixels are disposed at the same position in the detection pixel. The optical information detector of claim 8, wherein the light detection regions provided in the plurality of detection pixels have the same shape. In the arrangement structure of detection pixels for detecting light information of a plurality of data pixels, Detection pixels are arranged at a rate of n × n (n is a non-integer greater than 1) per one data pixel, and the detection pixels are located through the internal optical information area having a size smaller than the detection pixels. A detection pixel arrangement structure for detecting light information.

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