KR101435807B1 - Data image correcting method, recording medium reproducing method, and recording medium reproducing apparatus - Google Patents

Abstract

The present invention relates to a recording medium reproducing method and a recording medium reproducing apparatus. And more particularly, to a method and apparatus for correcting a data image when reproducing a data image from a recording medium.

A method of correcting a data image according to the present invention includes: determining whether a position of a reference mark in a data page is normally detected; Selecting a normal reference mark to be used for positional correction of the erroneously detected reference mark if the position of the reference mark is erroneously detected according to the determination result; And correcting the position of the reference mark that is erroneously detected using the selected adjacent reference mark.

Recording medium, data image, correction

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data image correcting method, a recording medium reproducing method,

The present invention relates to a recording medium reproducing method and a recording medium reproducing apparatus. And more particularly, to a method and apparatus for correcting a data image when reproducing a data image from a recording medium.

Due to recent developments in technology, high capacity and high density recording media have emerged. Examples of such a recording medium include a CD (Compact Disc) and a DVD (Digital Versatile Disc). In addition, there is a BD (Blu-ray Disc) which is a next generation recording medium which dramatically increases the recording capacity or a recording medium using holography. Particularly, in the case of a recording medium using holography, data can be superimposed on the volume of the recording medium by using the diffraction and interference characteristics of light, and the capacity thereof can be remarkably increased. However, in reproducing data, errors due to alignment of optical axes or errors between optical components may occur. Or errors due to the complexity of the image itself. A method and an apparatus for correcting such an error are needed.

The present invention relates to a method and apparatus for compensating for errors that may occur during data reproduction in a hologram.

A method of correcting a data image according to the present invention includes: determining whether a position of a reference mark in a data page is normally detected; Selecting a normal reference mark to be used for positional correction of the erroneously detected reference mark if the position of the reference mark is erroneously detected according to the determination result; And correcting the position of the reference mark that is erroneously detected using the selected adjacent reference mark.

Wherein the step of determining whether the position of the reference mark is normally detected comprises the steps of: comparing a detected position of each detected reference mark with a position of a known reference mark to obtain a first position difference; Obtaining a second position difference that is a difference of first position differences between adjacent reference marks using the first position difference of each reference mark; And determines that the reference mark is erroneously detected if the second position difference is equal to or larger than the threshold value.

And determines that the reference mark is normally detected when the second position difference is less than the threshold value.

And the threshold value is a predetermined value.

The selection of the normal reference mark for correcting the erroneously detected reference mark is characterized in that at least two normal reference marks adjacent to the erroneously detected reference mark are selected in each of the first direction and the second direction.

And the first direction and the second direction are parallel to the respective directions of the two-dimensional data image.

When the erroneously detected reference mark is a single erroneously detected reference mark, the adjacent normal reference mark can be selected only in one direction.

Wherein the step of correcting the detected reference mark position comprises the step of selecting at least two of the normally judged reference marks and estimating the position of the erroneously detected reference mark.

The estimation of the position of the erroneously detected reference mark is performed using an interpolation method when the erroneously detected reference mark is located between the normally detected reference marks.

The position of the erroneously detected reference mark is estimated by using an extrapolation method when the erroneously detected reference mark is located outside the reference marks that are normally detected.

According to another aspect of the present invention, there is provided a method of correcting a data image, comprising: determining whether a reference mark in a data page is normally detected; Determining a correction value in each direction by using the normally detected reference mark adjacent to the first direction and the second direction if the position of the reference mark is erroneously detected according to the determination result; And corrects the position of the reference mark which is erroneously detected by averaging the correction values obtained in the first direction and the second direction.

Wherein the step of determining whether the position of the reference mark is normally detected comprises the steps of: comparing a detected position of each detected reference mark with a position of a known reference mark to obtain a first position difference; Obtaining a second position difference that is a difference of first position differences between adjacent reference marks using the first position difference of each reference mark; And determines that the reference mark is erroneously detected if the second position difference is equal to or larger than the threshold value.

And the threshold value is a predetermined value.

The position of the erroneously detected reference mark can be corrected by utilizing the reference mark normally detected in only one of the first direction and the second direction if the erroneously detected reference mark is a single erroneously detected reference mark .

The step of obtaining the correction value in each direction estimates the position of the reference mark which is erroneously detected using the normally detected reference mark in each direction.

Wherein the estimation of the position of the erroneously detected reference mark is extrapolated or interpolated.

The correction value in each direction is obtained by finding a correction value in each direction with respect to each of the two-dimensional coordinates of the erroneously detected reference mark.

The average of the correction values obtained in each direction is characterized by averaging the correction values obtained for each two-dimensional coordinate of the erroneously detected reference mark.

According to another aspect of the present invention, there is provided a method of correcting a data image, comprising: detecting a position of a reference mark in a data page to determine whether a reference mark is normally detected; And classifying the plurality of erroneous reference marks into a single erroneous reference mark or a plurality of erroneous reference marks according to the number of erroneously detected reference marks; The first correction method is used when the erroneous detection reference mark is a single erroneous detection reference mark and the second correction method is used when the erroneous detection reference mark is a plurality of erroneous detection reference marks.

Wherein the step of determining whether the position of the reference mark is normally detected comprises the steps of: comparing a detected position of each detected reference mark with a position of a known reference mark to obtain a first position difference; Obtaining a second position difference that is a difference of first position differences between adjacent reference marks using the first position difference of each reference mark; And determines that the reference mark is erroneously detected if the second position difference is equal to or larger than the threshold value.

The first correction method estimates the position of the reference mark that is erroneously detected using at least two adjacent reference marks that are normally detected.

The second correction method includes: obtaining a correction value in each direction by utilizing a normally detected reference mark adjacent to the first direction and the second direction; And corrects the position of the reference mark which is erroneously detected by averaging the correction values obtained in the first direction and the second direction.

And the first direction and the second direction are parallel to respective directions of the two-dimensional data image.

Also, a recording medium reproducing apparatus according to the present invention includes: a light modulator for reading a reference mark in a data image; And corrects the positional information of the reference mark that is erroneously detected using the adjacent normal reference mark in the case of the erroneously detected reference mark according to the determination result, And a control unit.

The control unit may determine whether the position of the reference mark is detected by comparing the position of each read reference mark with the previously known position information of the corresponding reference mark to obtain a first position difference, A second position difference which is a difference between the two position differences is obtained; and when the second position difference is equal to or more than the threshold value, the reference mark is determined to be erroneously detected.

Wherein the control unit corrects the position of the reference mark that is erroneously detected using the adjacent normal reference mark, using at least two normal reference marks.

The controller corrects the position of the reference mark that is erroneously detected using the adjacent normal reference mark by using the position information of the normal reference mark to estimate the position of the reference mark that is erroneously detected.

The control unit uses the position information of the normal reference mark to estimate the position of the reference mark that is erroneously detected using the position information of at least two normal reference marks.

The control unit corrects the position of the reference mark that is erroneously detected using the normal reference mark by using the normal reference mark in the first direction and / or the second direction with respect to the erroneously detected reference mark And the position of the mark is corrected.

Also, a recording medium reproducing apparatus according to the present invention includes: a light modulator for reading a reference mark in a data image; And determining whether or not the read reference mark is misaligned. According to the determination result, in the case of an erroneously detected reference mark, the misalignment of the reference mark in the first direction and / And a control unit for obtaining a correction value.

The control unit may determine whether the reference mark is misaligned by comparing the position of each read reference mark with the known position information of the corresponding reference mark to obtain a first position difference, A second position difference which is a difference between the first position and the second position is obtained; and when the second position difference is equal to or more than the threshold, the reference mark is determined to be erroneously detected.

And the control section classifies the erroneously detected reference mark into a single erroneous detection or a plurality of erroneous detection.

Wherein the plurality of erroneous detections include two or more erroneously detected reference marks.

When the erroneously detected reference mark is a single erroneous detection, the controller corrects the position of the erroneously detected reference mark using the adjacent normal reference mark in the first direction or the second direction.

The control unit corrects the position of the erroneously detected reference mark using the normal reference mark in the first direction and the second direction when the erroneously detected reference mark is a plurality of erroneously detected.

Wherein when a plurality of erroneously detected reference marks are erroneously detected, the control section obtains correction values of reference marks erroneously detected in each direction using the normal reference marks in the first direction and the second direction, And the correction values in the two directions are averaged.

Wherein the first direction and the second direction are respectively the horizontal and vertical directions of the two-dimensional data image.

According to the data image compensation method and recording medium playback apparatus and method of the present invention, reliability of data at the time of playback of the recording medium can be ensured. In addition, it can effectively prepare for various disturbances. In addition, it is possible to effectively solve a cluster error that may occur in a complicated data image.

Hereinafter, preferred embodiments of a recording medium recording / reproducing method and a recording / reproducing apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

In addition, the term used in the present invention is selected from common terms that are widely used at present, but in some cases, there are terms selected arbitrarily by the applicant. In this case, the meaning is described in detail in the description of the present invention. It is to be understood that the present invention should be grasped as a meaning of a term that is not a name of the present invention.

In the present invention, the term "recording medium " means any medium on which data is recorded or recordable. For example, the term " recording medium " Hereinafter, the present invention will be described with reference to a disk as a recording medium, particularly, a "holography recording medium" for the convenience of explanation, but it should be apparent that the technical idea of the present invention is equally applicable to other recording media.

1 is an embodiment of a recording apparatus and / or reproducing apparatus according to the present invention. In FIG. 1, the general components are omitted and only the components necessary for explaining the technical gist of the present invention are shown. 1, a recording medium recording / reproducing apparatus according to the present invention includes a light source unit 11, first and second light split units 13 and 16, a light control unit 14, an optical modulation unit 15, A memory 17, an image sensor 18, and a control unit 20.

The light source unit 11 is composed of a gas laser, a solid-state laser, a semiconductor laser, a semiconductor diode, or the like that generates highly coherent light, for example, light such as a laser beam. In addition, a lens for collecting the light output from the light source unit 11 so as not to be dispersed, for example, a collimator lens, may be disposed at the output end.

The first light splitting unit 13 receives light output from the light source unit 11 and divides the light into a signal light and a reference light. The first light splitting unit 13 may be composed of one or more grating layers for diffracting light with one or more transparent substrates or a mirror for reflecting a part of light and passing the rest. Part of the light that has passed through the first light splitting section 13 is incident on the second light splitting section 16 and part of the light is incident on the light modulation section 15.

The optical modulator 15 generates signal light containing data by using the light output from the first light splitting unit 13 under the control of the control unit. For example, the optical modulation unit 15 may include binary data represented by monochrome dots in the signal light. At this time, for convenience, the white dot may be referred to as " On "and the black dot may be referred to as" Off ". Alternatively, it can be named.

In addition, the signal light may include data, in which a series of data including user data to be recorded by the user may be recorded. In addition to user data, recorded data includes control information and a mark for indicating a zone of data.

Further, the data generated from the light modulator 15 may be data having a two-dimensional image. Such data can be conveniently referred to as a "data image ". The data image can be expressed using binary dots of on (0n) / off (Off) as described above. In order to express each pixel of the data image in binary dot, the light modulator 15 may display the data image in pixel units or pixel block units, and may be controlled by the control unit.

A signal beam is irradiated to the recording medium 100, and a reference beam is irradiated to the recording medium. The reference beam is a beam that is incident on the first light splitting part and is incident on the recording medium via the light adjusting part 14. The reference beam is a beam that is incident from the first light splitting part into the second light splitting part.

The reference beam can be named with a reference beam. The reference beam refers to a beam that causes interference with a signal beam when data is recorded on the recording medium 100. [ Further, the reference beam means a beam used when reading data from the recording medium. However, as shown in FIG. 1, the reference beam and the reference beam may be used as those coming from the same light source. The light control unit 14 adjusts an incident angle, a direction, a wavelength, a phase, and the like of the second light according to the control of the control unit, thereby to input the second light to the recording medium 100.

At this time, different interference fringes are recorded on the recording medium in accordance with the phase and the wavelength of the reference beam. Therefore, the reference beam may be repeatedly and superimposedly recorded on the same area of the recording medium by changing the phase or wavelength of the reference beam. By using such a characteristic, the capacity of the holographic recording medium can be increased. That is, a plurality of data images can be recorded in one area.

Alternatively, a component called "first light output portion" may be used in the present invention as a component including both the light source and the characteristics of the first light splitting portion. Further, a component called "second light output portion" as an element including the light source and the second light splitting portion and the light control portion described above may be used in the present invention.

In recording the recording medium, both of the first and second light splitting sections should be used. On the other hand, at the time of reproduction of the recording medium, even if only the reference beam is used, the image recorded on the recording medium can be read. Therefore, according to the present invention, only the second divided light portion can be used at the time of reproducing the recording medium.

At the time of reproduction, information can be read by irradiating the recording medium with light having the same phase and wavelength as those used at the time of recording. Therefore, the phase, wavelength, incidence angle of the light control unit, etc. used in recording can be recorded or stored in the memory 17 and used at the time of reproduction.

Further, the memory 17 can store distortion characteristics and the like according to the recording apparatus. In addition, the memory may temporarily store the position of the reference pattern inserted in the data image, and may record the data on the recording medium. Further, the memory 17 may record the data stored on the recording medium under the control of the control unit or use it for recording / reproducing. In addition, the memory 17 may store data to be recorded on the recording medium, and may also store information other than user data among data recorded on the recording medium.

The image sensor 18 may be composed of a light detector such as a charge-coupled device (CCD) or a CMOS. It may also be composed of a plurality of optical detectors. For example, it may be composed of a plurality of optical detectors capable of providing resolutions such as 300 * 200, 1000 * 800, and the like. The image sensor 18 receives light reflected by the recording medium 100 or passes through the recording medium, and captures / reads a data image included in the received light. For example, the image sensor shown in Fig. 1 receives light passing through a recording medium. Or a phase conjugate signal light (corresponding to a data image) generated in a direction reflected from the recording medium. The image sensor may also be named as a light receiving portion.

The control unit 20 can read the data recorded in the memory 17 or the recording medium, generate new data, and provide the new data to the light modulation unit 15. In addition, the control unit 20 controls the light modulation unit 15 to generate a two-dimensional bitmap expressed by black and white dots of data read from the memory. Also, the control unit controls the light control unit 14 to adjust the intensity, incident angle, phase, wavelength, etc. of the second light that interferes with the first light. It is possible to store a plurality of data images (data pages) in the same area of the recording medium 100 by controlling the light control unit 14 as described above. Also, the light control unit 14 may be controlled so that a beam having the same condition as that at the time of recording is incident to reproduce the data image stored in the recording medium. The controller 20 can also detect light intensity (luminance) in two-dimensional directions of the data read by the image sensor 18, that is, x direction (horizontal) and y direction (vertical).

Also, the control unit 20 can correct the data image. As an example of a method of correcting a data image, there is a method of including a reference mark in advance of the position and pattern information in the data image. When reproducing the data image including the reference mark, the control unit 20 can measure the movement amount or the distortion amount of the reference mark to compensate the movement and distortion in the data image. When the position of the reference pattern is erroneously detected, the position of the read reference pattern may be compensated for and reflected in the data image compensation.

As the recording medium 100, a recording medium in the form of a disk or a volume can be used.

Fig. 2 is an embodiment in which a reference mark is inserted into a data image according to the present invention. The rectangles inserted at regular intervals in Fig. 2 represent reference marks. Using the reference mark, the data image can be divided into various zones to compensate the data image by zone. In addition, the data image can be compensated by measuring the movement amount of the reference mark or the like at the time of reproduction using the position and pattern of the reference mark that is known in advance. Further, although not shown directly in FIG. 2, user data and the like are included between reference marks. Although the reference patterns shown in Fig. 2 are inserted at regular intervals, it is obvious that the intervals of the reference patterns can be adjusted according to the optical characteristics of the recording / reproducing apparatus.

However, when the reference mark is read and the data image is compensated, it is required to relatively accurately read the position of the reference mark. If the position of the reference mark is erroneously detected, the data image can not be accurately compensated. In particular, when the position of the reference mark is erroneously detected, an error can be found throughout the region corresponding to the erroneously detected reference mark. This error can be called a cluster error.

FIG. 3 shows an example of a cluster error generated by erroneously detecting the position of the reference mark. 3 is an example of reproducing a data image represented by black and white dots. The area inside the circle in FIG. 3 is a densely packed white dot, which is generated by compensating the data image by erroneously reading the position of the reference mark corresponding to the area.

FIG. 4 is an example showing the movement amount of the reference mark when a cluster error occurs as shown in FIG. Each circle in FIG. 4 shows the position of the reference mark in the data image of the reference mark. In addition, the straight line attached to each circle indicates the movement direction and the movement amount of the reference mark. Here, the movement direction and the movement amount indicate the position movement amount and the movement direction of the reference mark read out for the reference mark which knows the position information in advance.

In FIG. 4, the row including the erroneously detected reference mark and the position of the erroneously detected reference pattern are shown to indicate the erroneously detected region of the reference pattern. The row including the erroneously detected reference mark is a rectangular box, and the position of the erroneously detected reference mark is represented by a circle. As shown in FIG. 4, it can be seen that, in the case of an erroneously detected reference mark, the amount of movement and the direction of movement are different from other neighboring reference marks.

X Y ΔX ΔY One -3.4783 3.4810 0 0 2 -2.7536 2.6407 0.7247 -0.8404 3 -1.9192 2.4569 0.8344 -0.1837 4 1.3734 -1.6174 3.2926 -4.0743 5 0.2778 1.3936 -1.0956 3.0110 6 0.8165 0.9137 0.5387 -0.4799 7 1.7582 0.2603 0.9417 -0.6535 8 2.5168 -0.3804 0.7587 -0.6407

Table 1 shows the amount of movement of the reference pattern shown in FIG. 4 as data. In particular, the movement amount of the reference mark of the row including the reference mark erroneously detected in FIG. 4 is represented by data. The left column with the serial number in Table 1 shows the position of each reference mark. That is, serial numbers such as 1, 2, ..., 8 are assigned to each reference mark in the square of FIG. 4 from the left.

In Table 1, X and Y represent the position of a previously known reference pattern and the read reference pattern position difference. In the case of the data image exemplified in the present invention, it is a two-dimensional data image. Therefore, two directions can be set in the data image. For example, the first direction and the second direction can be set. The first direction may be the horizontal direction of the data image, and the second direction may be the longitudinal direction of the data image. For convenience, in Table 1, X can be set as the difference in the horizontal direction, and Y can be set as the vertical difference. Further, the position difference X or Y of the position of the known reference pattern and the read reference pattern may be referred to as "first position difference ".

Also, in Table 1,? X represents the difference between adjacent X values. ΔX ₁ in the first row can be set to zero. In addition, ΔX ₂ in the second row can be expressed as follows.

ΔX ₂ = X ₂ -X ₁

In the same way, ΔX _n can be expressed as:

X _n = X _n -X _{n -1}

In the same way, ΔY _n can be expressed as follows.

ΔY _n = Y _n -Y _{n -1}

For convenience, ΔX and ΔY, which are differences between adjacent first position differences, can be called second position differences. When the position of a specific reference mark is erroneously detected, the value of the second position difference of the corresponding reference mark has a larger value than that of the surrounding other reference marks. Therefore, it is possible to determine whether or not the reference mark is erroneously detected using the second position difference. For example, referring to FIG. 4, it can be seen that the reference mark shown in the circle is erroneously detected. Referring to Table 1, it can be seen that the values of? X ₄ and? Y ₄ increase.

Fig. 5 shows an embodiment of a method for locating and correcting an erroneously detected reference mark and correcting the data image using the corrected reference mark. First, the first position difference is obtained using the known position information of the reference mark in the data image and the position information of the read reference mark (s10). As described above, the first position difference means a difference between a position of a reference mark that is known in advance and a position of a reference mark that is read out corresponding to the position of the reference mark. In addition, the first position difference can be obtained for each direction in the data image. As an example, the first position difference can be obtained for the first direction and the second direction. Further, the first direction and the second direction may be the horizontal direction or the vertical direction within the data image, respectively.

After the first position difference is obtained, the second position difference is obtained (s20). As described above, the second position difference is the difference in the first position difference of the adjacent reference marks. The fact that the second position difference suddenly increases means that the corresponding reference mark is erroneously detected. Also in the case of the second positional difference, it can be obtained in the first direction and the second direction.

After obtaining the second positional difference, the second positional difference is compared with the threshold value for each reference mark (s30). If the second position difference of each reference mark is smaller than the threshold value, the corresponding reference mark can be determined as the reference mark normally read (s50). If the difference between the second positions of the reference marks is greater than or equal to the threshold value, the corresponding reference mark can be determined as the reference mark in which the position is erroneously detected (s40).

Here, the threshold value can be set in various ways. As an example, the threshold value may be a predetermined value in the reproducing apparatus. It may be determined in advance at the time of shipment of the reproducing apparatus according to the characteristics of each reproducing apparatus. As another example, the threshold value may be a value that is determined while reproducing the recording medium. Alternatively, the threshold value may be a value obtained by averaging the movement amount of the reference mark or by other statistical processing.

If it is determined that the reference mark is a reference mark that has been erroneously detected, the position of the reference mark is corrected (s60). A method of correcting the position of the reference mark will be described later with reference to Figs. 6 to 13. Fig. After correcting the position of the erroneously detected reference mark, it can be used to correct the data image together with the normally detected reference mark (s70).

Figure 6 relates to a method for correcting erroneously detected reference marks according to the present invention. First, it is determined whether or not the position error of the reference mark is detected (s110). The above-described determination of whether or not the reference mark is erroneously detected can be referred to FIG. In the case of the erroneously detected reference mark, the type can be classified (s120). For example, as shown in FIG. 6, three types can be categorized. In addition, a correction method according to each type can be used. In addition, although not shown, it is possible to classify them into two types and use a correction method according to each type. It is to be understood that the idea of the present invention is not limited to the number of type classification.

As shown in FIG. 6, an example of a method of correcting a reference mark erroneously detected by three types is as follows. First, the first erroneous detection type and the remaining second erroneous detection type and the third erroneous detection type can be classified according to the position of the reference mark. For example, in the case of the first erroneous detection type, the erroneously detected reference mark is classified as the reference mark at the edge, and in the case of the second and third erroneous detection types, the erroneously detected reference mark is located at the non- can do.

Further, it can be classified according to whether the erroneously detected reference mark is located at a position other than the edge (second or third erroneous detection type), a single erroneous detection reference mark or a plurality of erroneously detected reference marks. For example, in the case of the second erroneous detection type, the erroneously detected reference mark can be classified as a single erroneously detected reference mark without being at the edge. Further, in the case of the third erroneous detection type, a plurality of erroneously detected reference marks can be classified without being erroneously detected. It will be obvious that various classification methods are possible. Here, a plurality of erroneous detection means a case where two or more erroneously detected reference marks exist.

FIG. 7 shows an embodiment of a method of correcting a false reference mark according to the present invention. Particularly, Figs. 7 (a) to 7 (c) show an example of the correction method for the case where the erroneous detection type is the first erroneous detection type described above. That is, it means a case where the erroneously detected reference mark is on the edge. As an example, an example of the first erroneous detection type is as shown in Figs. 7 (a) to 7 (c). In Figs. 7 (a) to 9 (c), a square without a pattern means a reference mark which is normally detected. In Fig. 7 (a) to Fig. 9 (c), a hatched square means a reference mark that is erroneously detected.

In Fig. 7 (a), the correction value for the position of the reference mark erroneously detected using the reference mark to the right of the reference mark I that is erroneously detected can be obtained. At the time of correcting the position of the reference mark which is erroneously detected using the normally detected reference mark, at least two normally detected reference marks can be used. For example, two normally detected reference marks are used in Figs. 7 (a) to 7 (c).

An example of a method of correcting the position of a reference mark erroneously detected using two normally detected reference marks in FIG. 7 (a) is as follows. First, the first position difference of the normal reference marks (II, III) is obtained. The first position difference means the difference between the position of the reference mark previously known and the position of the reference mark read out as described above.

An interpolation method can be used as a method of obtaining the position difference of the reference mark that is erroneously detected using the normal reference mark (II, III). In particular, for reference marks at the edges, extrapolation may be used. As an example of extrapolation, the following equation can be used.

Here, n may indicate the relative position of the erroneously detected reference mark and the normally detected reference mark, and this value may be arbitrarily determined. For example, in the case of FIG. 7A, the erroneously detected reference mark I can be set as x (1), y (1), and each of the normally detected reference marks II, , y (2), and x (3), y (3). A _x , b _x can be obtained by using x (2), x (3) of the reference mark which is normally detected. In the same way using y (2), y (3 ) can be determined a _y, b _y. a _x , b _x And a _y , b _y Then, x (1) and y (1) can be obtained.

In the same manner, the position of the reference mark erroneously detected can be obtained by using the normal reference marks II 'and III' above the reference mark I which is also erroneously detected in FIG. 7 (b). For convenience, the position of the erroneously detected reference mark obtained by using the reference marks (II ', III') can be set to x '(1) and y' (1).

Also in FIG. 7 (c), the positions of the reference marks erroneously detected can be obtained by using the normal reference marks II " and III " below the reference mark I which is erroneously detected. For convenience, the position of the erroneously detected reference mark obtained by using the reference mark (II ", III") can be set to x "(1) and y" (1).

The embodiment shown in Figs. 7 (a) to 7 (c) includes three sets of reference marks 7 (a), 7 (b), and 7 (b) normally detected for one erroneously detected reference mark I c) can be used to obtain an estimate for the erroneously detected reference mark for each set. At this time, it is desirable to reflect the tendency of each set of the erroneously detected reference marks, so it is desirable to average the values obtained in 7 (a) to 7 (c).

That is, if the corrected position of the erroneously detected reference mark is (x, y)

.

In the embodiments shown in Figs. 7 (a) to 7 (c), although the positions of the reference marks that are erroneously detected using the linear equation are corrected, a higher order equation of a quadratic equation or more can be used. However, when correction is made using a higher order formula, the number of normal reference marks required may be increased. In addition, a higher capacity system may be required. It is obvious that the desired correction formula can be changed depending on the performance of the recording / reproducing apparatus and the desired degree of correction.

Fig. 8 (a) shows an embodiment of the correction method when the type of the erroneously detected reference mark corresponds to the second type. In other words, the erroneously detected reference mark is a single erroneously detected reference mark and the erroneously detected reference mark is not at the edge. At this time, the normal reference mark can be selected from the normal reference marks adjacent to the reference mark that is erroneously detected. For example, in Figs. 8 (a) and 8 (b), normal reference marks in the horizontal and vertical directions of the erroneously detected reference marks are selected. The horizontal and vertical directions may be referred to as a first direction and a second direction. Further, the first direction and the second direction are not limited to the horizontal direction and the vertical direction within the data image, but may refer to respective directions in which the reference marks are arranged in the data image.

The position of the reference mark I that is erroneously detected in FIG. 8A can be corrected using the positions of the normal reference marks II and III in the adjacent transverse direction. At this time, the position may mean the first position difference described above. At this time, the corrected position of the erroneously detected reference mark I can be obtained by using a value obtained by averaging adjacent normal reference marks. (2), (3), (3), and (4), the position of the reference mark which is normally detected is referred to as (x , y (3)), the corrected position of the reference mark, which is erroneously detected in Fig. 8 (a)

,

,

.

In the same way, the corrected position of the reference mark, which is erroneously detected in FIG. 8 (b), can be obtained as follows. The positions of the reference marks II 'and III' which are normally detected in FIG. 8 (b) are denoted by (x '(2), y' (2) , The corrected position (x '(1), y' (1)) of the erroneously detected reference mark can be obtained as follows.

,

,

At this time, the corrected position values of the erroneous detection reference marks obtained in Figs. 8 (a) and 8 (b) are averaged again, and the corrected erroneously detected reference marks can be obtained. Alternatively, any of the correction values obtained in 8 (a) or 8 (b) for convenience of reference marks can be used. That is, the correction value of the reference mark that is detected erroneously in the horizontal or vertical direction of the data image may be obtained, and then the correction value for each direction may be averaged. Alternatively, the correction value of the reference mark that is erroneously detected in the horizontal direction or the vertical direction may be obtained and used. Further, as described above, the lateral direction and the longitudinal direction can be named as the first direction or the second direction. Further, the first direction and the second direction are not limited to the horizontal and vertical directions of the data image, but are related to the placement directions of the reference marks in the data image.

Figs. 9 (a) to 9 (c) show an embodiment of a correction method of the erroneously detected reference mark classified as the third type. That is, this means that there are two or more reference marks that are not detected at the edge but are erroneously detected.

9 (a) shows an embodiment in which correction values are obtained in the horizontal direction. The method of obtaining the correction value in the horizontal direction can be expressed by Equation (1).

Here, the normal reference marks I and IV in the lateral direction can be used. Here, the reference marks are used in order from the left. That is, the positional values of the reference marks I, II, III and IV can be set to (x (1), y (1)), ... (x (4), y (4)). Here, the position may mean the above-described first position difference.

First, the coefficients a _x , b _x , a _y , and b _y can be obtained using the normal reference mark (I, IV). (2), y (2)) and (x (3), y (3)), which are the correction values of the reference marks, are obtained by substituting n = 2 and n = .

Fig. 9 (b) is an example of obtaining a correction value in the vertical direction with respect to the reference mark II which is erroneously detected. As an example, a correction value can be obtained in the vertical direction using the normally detected reference mark II 'II' '. For example, the equation (1) can also be used in the case of FIG. 9 (b). Or an average value of the reference mark II 'II' that is normally detected can be used. For the erroneously detected reference mark II, a correction value for the reference mark II which is finally erroneously detected can be obtained by averaging the correction value in the horizontal direction and the correction value in the vertical direction.

Fig. 9 (c) is an example of obtaining a correction value in the vertical direction for the reference mark III which is erroneously detected. As an example, a correction value can be obtained in the vertical direction by using the reference mark III 'III' which is normally detected. For example, the equation (1) can also be used in the case of FIG. 9 (b). Or an average value of the reference mark III 'III' that is normally detected can be used. For the erroneously detected reference mark III, a correction value for the reference mark III finally detected by averaging the correction value in the horizontal direction and the correction value in the vertical direction can be obtained.

In the embodiments of Figs. 9 (a) to 9 (c), in correcting the erroneously detected reference mark, the correction value may be obtained only in either the horizontal or vertical direction. As an example, only correction values in the vertical direction can be used for the erroneously detected reference marks II and III. It is obvious that various embodiments can be used as to whether or not to use the correction value obtained from a specific direction.

7A to 7C, an example of obtaining the correction value of the false detection reference mark classified as the first type is shown in Figs. 8A and 8B, FIGS. 9A to 9C show examples of obtaining correction values of the detection reference marks. In FIGS. 9A to 9C, correction values of the error detection reference marks classified into the third type are obtained.

However, in the case of the first type, the number of adjacent normal reference marks may be less than the second type and the third type because they are at the edge. Therefore, in the case of the first type, a correction value can be obtained for a larger number of sets, and the value can be averaged. As an example, a correction value for three sets of normal reference marks can be obtained.

10 is a view showing the movement amount of the reference pattern shown in FIG. 4A corrected by the above-described method. In the case of FIG. 4A, the amount of movement of the reference pattern inside the circle is different from that of the surroundings. In FIG. 10A, it can be seen that it is similar to the surroundings. At this time, as an example of the correction method, the embodiment shown in Fig. 8 (a) can be used. In other words, it is possible to correct the correction value to the correction value obtained by using the normal reference mark in the horizontal direction.

Fig. 11 shows the correction of the cluster error shown in Fig. 3 using the correction method according to the present invention. That is, in the case where a cluster error of a data image occurs due to erroneous detection of a reference mark (FIG. 3), an erroneously detected reference mark is found and its position is corrected using an adjacent normal reference mark. Compared with FIG. 4, it can be seen that the cluster error has been eliminated.

12 shows another embodiment of the data image correcting method according to the present invention. First, it is determined whether or not the read reference mark is normal (s210). Here, whether or not the read reference mark is normal can be obtained by using the first position difference and the second position difference between the read reference marks. For example, when the second position difference is out of the threshold value, the corresponding reference mark can be judged to be erroneously detected. If it is determined that the reference mark is normally detected, the position information of the reference mark can be used without correction. Conversely, if it is determined that the reference mark is erroneously detected, the position information of the corresponding reference mark is corrected. For this, a reference mark normally detected in the first direction can be selected (s220).

The first direction and the second direction may arbitrarily select two directions within the data image. For example, the horizontal and vertical directions of the data image can be set to the first direction and the second direction, respectively. In addition, the selection of the reference mark normally detected in the first direction can be made by selecting a normally detected reference mark closest to the erroneously detected reference mark. For example, in the case of a plurality of reference marks which are detected as erroneous, it is possible to select the nearest normal reference mark in a plurality of erroneously detected areas. In addition, at least two or more normal reference marks to be selected can be selected.

The normal reference mark in the first direction for correcting the erroneously detected reference mark may be selected and corrected using the selected normal reference mark (s230). The correction method may be extrapolation or interpolation. The extrapolation method is described in detail in Figs. 7 (a) to 7 (c), and the interpolation method and the like can be described with reference to Figs. 8 (a) to 9 (a).

After determining the correction value in the first direction, the normal reference mark adjacent in the second direction can be selected (s240). The method of selecting the normal reference mark adjacent in the second direction is the same as the method of selecting the normal reference mark adjacent in the first direction.

Further, a correction value in the second direction can be obtained in the same way as the correction value is obtained in the first direction (s 250). The correction value in the first direction and the correction value in the second direction are obtained, and then the correction values in the respective directions can be averaged (s260). This is to sufficiently utilize the information of the normally detected reference mark around the erroneously detected reference mark. Alternatively, only one of the correction values in the first direction or the second direction may be used depending on the characteristics of the recording / reproducing apparatus or the manufacturer or the user's selection.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments but should be determined according to the claims.

1 shows an embodiment of a recording medium recording / reproducing apparatus according to the present invention.

FIG. 2 shows an embodiment in which a reference mark is inserted into a data image according to the present invention.

Fig. 3 shows an example of an error caused by the reference mark erroneous detection.

Fig. 4 shows an example of errors caused by the reference mark erroneous detection.

FIG. 5 shows an embodiment of a data image correction method according to the present invention.

6 shows an embodiment of a data image correction method according to the present invention.

7 (a) to 7 (c) show an embodiment of a data image correcting method according to the present invention.

8 (a) and 8 (b) illustrate an embodiment of a data image correction method according to the present invention.

9 (a) to 9 (c) show an embodiment of a data image correcting method according to the present invention.

FIG. 10 shows an example in which a data image is corrected when a data image correction method according to the present invention is used.

FIG. 11 shows an example in which a data image is corrected when a data image correction method according to the present invention is used.

12 shows an embodiment of a data image correcting method according to the present invention.

Claims (37)

Determining whether a position of a plurality of reference marks in a data page is normally detected; Selecting an adjacent normal reference mark to be used for positional correction of the erroneously detected reference mark if at least one of the reference marks is erroneously detected according to the determination result; And correcting the position of the erroneously detected reference mark using the selected normal reference mark. The method according to claim 1, Wherein the step of determining whether the position of the reference marks is normally detected comprises: Comparing the detected position of each detected reference mark with a position of a known reference mark to obtain a first position difference; Obtaining a second position difference that is a difference of first position differences between adjacent reference marks using the first position difference of each reference mark; And determining that the reference mark whose second position difference is equal to or higher than the threshold is erroneously detected. 3. The method of claim 2, And determines that the reference mark having the second position difference less than the threshold is normally detected. The method according to claim 2 or 3, Wherein the threshold value is a predetermined value. The method according to claim 1, The selection of the adjacent normal reference mark for correction of the erroneously detected reference mark may be made by, Wherein at least two of the normal reference marks adjacent to the erroneously detected reference mark are selected in the first direction and the second direction, respectively. 6. The method of claim 5, Wherein the first direction and the second direction are parallel to respective directions of the two-dimensional data image. 6. The method of claim 5, Wherein when the erroneously detected reference mark is a single erroneously detected reference mark, the adjacent normal reference mark is selected only in one direction. The method according to claim 1, The step of correcting the position of the erroneously detected reference mark includes: Wherein at least two of the normally determined reference marks are selected to estimate the position of the erroneously detected reference mark. 9. The method of claim 8, The estimation of the position of the erroneously detected reference mark may be performed, And when the erroneously detected reference mark is located between the normally detected reference marks, estimating the erroneous data using the interpolation method. 9. The method of claim 8, The estimation of the position of the erroneously detected reference mark may be performed, And when the erroneously detected reference mark is located outside of the normally detected reference marks, extrapolating is performed. Determining whether a position of a plurality of reference marks in a data page is normally detected; Determining a correction value in each direction by using a normally detected reference mark adjacent to the first direction and the second direction when at least one of the reference marks is erroneously detected according to the determination result; And averaging the correction values obtained in the first direction and the second direction to correct the position of the erroneously detected reference mark. 12. The method of claim 11, Wherein the step of determining whether the position of the reference marks is normally detected comprises: Comparing the detected position of each detected reference mark with a position of a known reference mark to obtain a first position difference; Obtaining a second position difference that is a difference of first position differences between adjacent reference marks using the first position difference of each reference mark; And determining that the reference mark whose second position difference is equal to or higher than the threshold is erroneously detected. 13. The method of claim 12, Wherein the threshold value is a predetermined value. 12. The method of claim 11, When the erroneously detected reference mark is a single erroneously detected reference mark, the position of the erroneously detected reference mark is corrected by utilizing the reference mark normally detected in only one of the first direction and the second direction / RTI > 12. The method of claim 11, Wherein the step of obtaining the correction value in each direction estimates the position of the erroneously detected reference mark by using the normally detected reference mark in each direction. 16. The method of claim 15, Wherein the estimation of the position of the erroneously detected reference mark is extrapolated or interpolated. 12. The method of claim 11, Wherein a correction value in each direction is obtained by obtaining a correction value in each direction with respect to each of two-dimensional coordinates of the erroneously detected reference mark. 12. The method of claim 11, Wherein the average of the correction values obtained in each direction is obtained by averaging the correction values obtained for each of the two-dimensional coordinates of the erroneously detected reference mark. Detecting a position of a plurality of reference marks in the data page and determining whether the position of the reference mark is normally detected; Determining the number of erroneously detected reference marks if at least one of the reference marks is erroneously detected according to the determination result; And correcting the corrected data by a first correction method when the number of erroneously detected reference marks is one, and correcting the number of erroneously detected reference marks by using a second correction method. 20. The method of claim 19, Wherein the step of determining whether the position of the reference marks is normally detected comprises: Comparing the detected position of each detected reference mark with a position of a known reference mark to obtain a first position difference; Obtaining a second position difference that is a difference of first position differences between adjacent reference marks using the first position difference of each reference mark; And determining that the reference mark whose second position difference is equal to or higher than the threshold is erroneously detected. 20. The method of claim 19, Wherein the first correction method estimates the position of the erroneously detected reference mark using at least two adjacent reference marks that are normally detected. 20. The method of claim 19, The second correction method includes: obtaining a correction value in each direction by utilizing a normally detected reference mark adjacent to the first direction and the second direction; And averaging the correction values obtained in the first direction and the second direction to correct the position of the erroneously detected reference mark. 20. The method of claim 19, Wherein the first direction and the second direction are parallel to respective directions of the two-dimensional data image. An optical modulator for reading a plurality of reference marks in a data image; Determining whether or not a position error of the read reference marks is detected, And corrects the erroneous position information of the reference mark using the adjacent normal reference mark when at least one of the reference marks is erroneously detected according to the determination result. Recording medium reproducing apparatus. 25. The method of claim 24, The control unit may determine whether or not the position error of the read reference marks is detected, Comparing the position of each read reference mark with previously known position information of the corresponding reference mark to obtain a first position difference, obtaining a second position difference that is a difference of first position differences between adjacent reference marks, And determines that the reference mark whose second position difference is equal to or greater than the threshold value is erroneously detected. 25. The method of claim 24, The control unit corrects the position of the erroneously detected reference mark using the adjacent normal reference mark, Wherein at least two normal reference marks are used. 25. The method of claim 24, The control unit corrects the position of the erroneously detected reference mark using the adjacent normal reference mark, And estimates the position of the erroneously detected reference mark using the positional information of the adjacent normal reference mark. 28. The method of claim 27, Wherein the control unit uses the position information of the adjacent normal reference mark to estimate the position of the erroneously detected reference mark using the position information of at least two adjacent normal reference marks. 28. The method of claim 27, The control unit corrects the position of the erroneously detected reference mark using the adjacent normal reference mark, And corrects the position of the erroneously detected reference mark using the normal reference mark adjacent to the erroneously detected reference mark in the first direction or the second direction. An optical modulator for reading a plurality of reference marks in a data image; Determining whether or not a position error of the read reference marks is detected, and if at least one of the reference marks is erroneously detected according to the determination result, using the normally detected reference mark adjacent in the first direction and / And obtaining a correction value in each direction. 31. The method of claim 30, The control unit may determine whether the reference marks are misaligned, Comparing the position of each read reference mark with previously known position information of the corresponding reference mark to obtain a first position difference, obtaining a second position difference that is a difference of first position differences between adjacent reference marks, And determines that the reference mark whose second position difference is equal to or greater than the threshold value is erroneously detected. 31. The method of claim 30, Wherein the control section classifies the erroneously detected reference mark into a single erroneous detection or a plurality of erroneous detection. 33. The method of claim 32, Wherein the plurality of erroneous detections include two or more erroneously detected reference marks. 33. The method of claim 32, Wherein when the erroneously detected reference mark is a single erroneous detection, the control unit corrects the erroneously detected reference mark position using the adjacent normal reference mark in the first direction or the second direction. Device. 33. The method of claim 32, Wherein the control unit corrects the position of the erroneously detected reference mark using the normal reference mark adjacent in the first direction and the second direction when a plurality of erroneously detected reference marks are erroneously detected, . 36. The method of claim 35, When the erroneously detected reference marks are a plurality of erroneous detections, the control section obtains correction values of reference marks erroneously detected in each direction using the normal reference marks adjacent in the first direction and the second direction, And corrects the correction values in the first direction and the second direction. 35. The method according to claim 34 or 35, Wherein the first direction and the second direction are the horizontal and vertical directions of the two-dimensional data image, respectively.

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