JP2000149257A - Method for recording information signal and optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable information signals to be recorded on the recording face of an optical recording medium using a hologram hard to be forged. SOLUTION: In this method, a hologram showing an additional information signal is recorded in the two-dimensional area a, b:101 on the face of an optical recording medium 100 having a spiral or concentric track, and the contents information is encoded in variable length and recorded in the areas A, B, C other than the two-dimensional area so that it becomes a user data area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recording information signals such as a serial number of a disk and copyright protection information for protecting the copyright of the content recorded on the disk on an optical recording medium. The present invention relates to an information signal recording method and an optical recording medium thereof.

[0002]

2. Description of the Related Art An example of an optical disk has a diameter of 12c.
m, a recording capacity of 4.7 GB, a video signal information compressed by the MPEG compression variable transfer rate method, recorded, and reproduced, a reproduction-only type DVD (digital video disc, digital versatile disc) )
In addition, research and development of a recording / playback type DVD are being conducted. As a conventional method of recording the serial number and copyright protection information on an optical disk, a method of recording the data on a BCA (burst cutting area) of a DVD is known.

[0003] BCA is a technical research report of IEICE.
R97 29-34, pages 33-38, "Techniques for Recording Additional Information on DVD ROM Disks"
A signal similar to a barcode is written in a circular arc direction by a high-power laser beam inside the lead-in area of the D-board,
At the time of reproduction, the change in the amount of reflected light is read out using the optical pickup of the player. However, the method of recording a barcode information signal on the BCA of a disk has a problem that it is easy to forge because a YAG laser beam whose beam diameter can be narrowed down to only about 10 μm is used.

Another conventional example is disclosed in, for example, JP-A-8-8
As disclosed in Japanese Patent No. 3440, a method of recording a hologram for identifying a recording medium in an “area other than the information recording area” has been proposed. Further, for example, Japanese Patent Laid-Open No.
Japanese Patent Laid-Open Nos. 3929, 10-143603 and 10-198259 disclose, for example, an optical card instead of a magnetic card and two-dimensional information representing card information in order to make it difficult to forge a prepaid card. Hologram (CG)
H: Computer Generated Hologram), which is then drawn on a master plate with a submicron-order resolution uneven pattern, then duplicated on an optical card, and coherent light is irradiated onto the optical card during playback. A method has been proposed in which a two-dimensional CCD image sensor is used to read a real image and reproduce an original image.

[0005]

By the way, it is conceivable that an information signal is recorded in the "information recording area" of the optical disc by using a hologram which is difficult to forge, instead of "the area other than the information recording area". However, there is a problem that it is difficult to secure a two-dimensional area for recording such a hologram on an optical disc on which content information is recorded along a spiral track.

Accordingly, an object of the present invention is to provide an optical recording medium capable of recording an information signal in an information recording area with a hologram that is difficult to forge.

[0007]

In order to achieve the above object, the present invention secures a two-dimensional area on a recording surface of an optical recording medium and records a hologram, and this two-dimensional area becomes a user data area. As described above, the content information is variable-length coded and recorded in another area. That is, according to the present invention, a hologram representing additional information is secured in the two-dimensional area by securing a predetermined two-dimensional area extending over the plurality of tracks of the optical recording medium on which a spiral or concentric track is formed. Recording the user data area of the content information to be recorded on the recording medium.
An information signal recording method is provided, comprising: a step of performing variable-length encoding of the content information so as to match a dimension area; and a step of recording the variable-length encoded content information along the track. .

According to the present invention, a hologram representing an additional information signal is recorded in a predetermined two-dimensional area extending over the plurality of tracks on the optical recording medium on which a spiral or concentric track is formed. An optical recording medium is provided in which the content information is variable-length coded so that the user data area of the content information to be matched with the two-dimensional area and recorded along the track.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a variable length encoding device for realizing an embodiment of an information signal recording method and an optical recording medium according to the present invention, FIG. 2 is a block diagram showing a decoding device, and FIG. FIG. 4 is an explanatory diagram showing a recording area of the hologram of FIG. 3, FIG. 5 is an explanatory diagram showing a hologram, FIG. 6 is a configuration diagram showing a recording device, and FIG. 7 is a configuration diagram showing a hologram reproducing device. FIG.

As the content information recorded on the optical recording medium, compressed data of images and sounds can be considered. As a compression method, an MPEG (Moving Picture Experts Group) method is often used. MPEG was developed in 1988 by ISO / IEC J to consider video coding standards.
It is an organization established by TC1 / SC (International Organization for Standardization / International Electrotechnical Commission Meeting Technical Committee 1 / Special Committee 2).
MPEG1 (MPEG phase 1) is 1.5Mbps
JPEG, which is a standard for storage media of the order of magnitude and is intended for still image coding, and H.264 for moving image compression for low transfer rates of ISDN video conferences and video telephones. 261 (CCITT SGXV, current ITU-
TSG15 (standardized by TSG15), which is a standard that inherits the basic technology and introduces new technology for storage media.
It was established in August 1993 as ISO / IEC11172. MPEG2 is a general purpose standard that can support various applications such as communication and broadcasting.
In November 1994, ISO / IEC 13818, H.E. 262
It is established as.

The MPEG system combines several technologies. First, as shown in FIG. 1, a difference between the previous image decoded by the motion compensation predictor 1 and the input image is added to an adder 2.
, The time redundancy of the input image is reduced. The prediction direction includes past, future, and both modes, and these modes can be switched and used for each macroblock (MB) of 16 pixels × 16 pixels. The prediction direction is determined based on three picture types (P
Picture, B picture, I picture). The P picture has two modes: a mode in which encoding is performed by predicting from the past, and a mode in which the macroblock is independently encoded without performing prediction. A B-picture is a mode that predicts and encodes from the future, a mode that predicts and encodes from the past, a mode that predicts and encodes from both, and a mode that independently encodes its macroblock without predicting There are four modes. I-pictures have one mode that encodes all macroblocks independently.

A group from a picture to a picture before the next I picture is called a GOP (Group Of Picture). When this GOP is used in a storage medium or the like, it is generally composed of about 15 pictures. MPE
In G data, a start code is called a start code, and the start of a sequence or the start of a picture is described by a byte-aligned code that can be uniquely identified. Following the user start code, a user data area where the user can write free data is sequenced, GO
P, can be set after the picture header.

The motion compensation predictor 1 shown in FIG. 1 performs pattern matching on a motion area for each macroblock, detects a motion vector with half-pel accuracy, and shifts the motion vector by the amount of motion to predict the motion of an image. The motion vector has a horizontal direction and a vertical direction, and a motion compensation (M
C: Motion Compensation mode (prediction mode) and variable-length coding (V
LC) device 5.

The difference image calculated by the adder 2 is D
The orthogonal transform is performed by a CT (discrete cosine transform) unit 3.
DCT is an orthogonal transform method for discretely transforming an integral transform using a cosine function as an integral kernel into a finite space.
A macroblock of pixels × 16 pixels is divided into 4 parts, and 8 × 8
Two-dimensional DCT is performed on the DCT block of pixels. D
The CT-processed image data (DCT coefficients) is quantized by the quantizer 4. At this time, the quantizer 4 sets a value obtained by multiplying a two-dimensional frequency in the 8 × 8 quantization matrix by a visual characteristic and a value obtained by multiplying the whole by a scalar-multiplied quantization scale as a quantization value, as a DCT coefficient. Is divided by its quantized value. When inverse quantization is performed on the decoder side, the value is approximated to the original DCT coefficient by multiplying by a quantization value.

The data quantized by the quantizer 4 is:
The variable length coding (VLC) unit 5 performs variable length coding. At this time, of the quantized data, direct current (DC)
The components are subjected to DPCM (differential PCM) and an alternating current (A
The component C) is zigzag-scanned from the low-frequency component to the high-frequency component, and Huffman coding is performed by assigning a code having a short code length to a coefficient having a high frequency of occurrence, using a run length of zero and an effective coefficient value as one event.

The variable-length coded data is stored in the temporary buffer 6 and output as coded data at a predetermined transfer rate. At this time, although not shown,
The error code amount between the code generation amount and the target code amount for each macroblock of the output data is fed back to the quantizer 4,
The quantization scale of the quantizer 4 is controlled so that the code generation amount becomes the target code amount. Therefore, by setting the target code amount, the layout of the variable-length encoded data on the disk can be arbitrarily controlled.

The data quantized by the quantizer 4 is
The image is decoded into a difference image by the inverse quantizer 7 and the inverse DCT unit 8. This difference image is stored in the image memory 10 via the adder 9, and is used as a reference for the motion compensation predictor 1 to calculate the next difference image. MP like this
The EG compressed data is subjected to variable length decoding (VLD), inverse quantization, inverse DCT and the like by the decoding device shown in FIG. 2 and is decoded into the original image. The MPEG compressed data is Huffman-coded as described above, and the code length is variable. Therefore, by controlling the code amount, any part can be replaced with MPEG user data. Therefore, in the present invention, a hologram (interference fringe pattern in holography) representing additional information such as a disk serial number or copyright protection information for protecting the copyright of the content recorded on the disk is recorded on a plurality of tracks. Is recorded in a two-dimensional area extending over the content information, and the content information is variable-length encoded and recorded so that the two-dimensional area matches the position of the MPEG user data of the content information. Note that the content information can be recorded after the hologram representing the additional information is recorded first, and these two types of information can be recorded in the reverse order. That is, the content information may be recorded along the track, and the hologram representing the additional information may be recorded so as to match the user data area.

FIG. 3A shows an MPE on an optical disc 100.
A state where the hologram 101 is recorded in a two-dimensional area as G user data is shown. FIG. 3B shows the positional relationship between the MPEG compressed data and the hologram in one track when the hologram 101 shown in FIG. 3A is recorded. That is, according to the present invention, a predetermined two-dimensional area of the optical recording medium in which a plurality of spiral or concentric tracks are formed, and an area that straddles the plurality of tracks is first set. The additional information is converted into a hologram and recorded. Next, content information to be originally recorded is stored in an MPEG compressed data (variable length coded data) area A,
Record in B and C. In this case, in order to record the variable length coded data in the areas A, B, and C, the addresses of the user data areas a and b as the two-dimensional areas for recording the hologram on the disc are detected in advance, and the addresses are detected. What is necessary is just to configure the variable length coded data so as to avoid it. The size of the user data areas a and b can be calculated based on the track position, the data amount of the hologram data, and the arrangement position. Based on the size of the user data areas a and b, the variable length coded data area A, B, C can be calculated.

Here, in the case of MPEG image data, an area for arranging 4-byte user data is provided after the picture header, and when the user data is described in the area, the user data can be freely allocated until the next slice start code. Can be described. Therefore, in order to record a hologram in this user data area, the encoding apparatus sets the end position of the variable-length encoded data areas A, B, and C to the picture header +
The user data areas a and b are secured by controlling the code amount so as to be 4 bytes. However, in the case of a disk having a constant linear velocity (CLV), the recording length is 2π × track pitch (DVD: 0.74 μm) for each rotation from the inner circumference to the outer circumference.
m) = 4.65 μm, so that it is necessary to adjust the phase by this amount for each track.

The format will be described with reference to FIG. A series of parameters starting from the picture start code are picture headers specified in the MPEG standard. Note that parameters in parentheses are parameters that need to be described only when necessary. An area A immediately before the user data area a describes a user data start code, an area B immediately after the user data area a describes a slice start code, and thereafter describes MPEG image data. Therefore, by controlling the code amount of the MPEG image data, the hologram data can be stored in the two-dimensional area a, without inconvenience in the variable length code.
b.

Here, as an example, since the track pitch of the DVD is 0.74 μm, 1/3 = about 0.25
The pitch of μm is set to the resolution of the hologram 101 in the disk radial direction. The pitch of the channel bit length of the DVD = about 0.13 μm is set as the resolution of the hologram 101 in the disk trace direction. Further, since the error correction capability of the DVD standard is 6 mm in recording length, the size of a two-dimensional area of one (one block) of the holograms 101-1 to 101-3 is 0.1 mm ×
It is set to be 0.1 mm or more and 2 mm × 2 mm or less.

Here, when one block is composed of a plurality of holograms, the size of the two-dimensional area of one hologram is desirably about 0.3 mm × 0.3 mm for the reason of the detection S / N ratio. Is a maximum of 6 × 6 in one block =
36 hologram patterns (the size of one block is 1.8 mm × 1.8 mm) can be recorded. Then, these 36 hologram patterns are divided into 5 × 7 groups (one is not used), and one group is represented by 5 bits. Forge 2 bits, for example, "1" of the 5-bit in consideration of, using the remaining three bits fixed to "0", to represent the decimal one digit by one group by ₅ C ₂ = 10 Therefore, seven decimal digits can be represented by one block having a size of 2 mm × 2 mm or less. In this example, if one bit is rewritten by forgery and originally two bits are “1”, but three bits are “1”, it can be determined that the product is a counterfeit product.

FIG. 5 shows a two-dimensional original image data "A" shown in FIG.
(Input data) is numerically calculated by a computer, and FIG.
FIG. 5B shows that the brightness distribution data of the hologram shown in FIG. 5B is created and is recorded in each section of the optical disc divided by a grid of orthogonal coordinates as shown in FIG. 5C. Here, as an example, the track pitch of the DVD is 0.
Since the pitch is 74 μm, the grating is divided at a pitch of 1/3 = about 0.25 μm in the radial direction of the disk. Also, DV
The length of the channel bit of D = pitch of about 0.13 μm divides the disk trace direction of the grating.

FIG. 6 shows a recording medium 609 as an example.
1 shows an apparatus for manufacturing a VD master. A stamper is manufactured based on the master 609, and a final DVD is manufactured based on the stamper. The light source 605 in the case of a DVD is generally a krypton laser having a wavelength of 352 nm, and this laser light is applied to a master 609 via an optical modulator 606, an optical deflector 607, and an objective lens 608. An uneven pattern for pits and holograms is formed on the substrate. First digital modulator 6
To 01, a signal obtained by EFMplus-modulating the MPEG compressed data and a hologram pattern intensity signal are selectively applied. The first digital modulator 601 adds a predetermined synchronizing signal and the like to these input signals and sends them to the optical modulator driving circuit 603. The optical modulator driving circuit 603 amplifies the input signals to a predetermined voltage. To drive the optical modulator 606.

Here, for example, a hologram as shown in FIG.
When the laser light is formed in the two-dimensional area on the track 9, it is necessary to shift the laser light in the track width direction. Therefore, the hologram pattern deflection signal indicating the amount of deviation from the track center is transmitted to the second digital modulator 602 and the optical deflector drive circuit 604.
To shift the laser light in the width direction of the track by converting the driving voltage into the driving voltage of the optical deflector 607. As an example, since the track pitch of the DVD is 0.74 μm, the deviation amount is −0.2
It may be about 5 μm, 0 μm, and +0.25 μm. A detailed configuration for recording at a position deviated from the track center using an optical deflector is described in, for example, Japanese Patent Application Laid-Open No. 8-69624 filed by the applicant of the present invention, and therefore detailed description is omitted. I do.

In this example, the case where the hologram is recorded on the DVD master 609 has been described.
9 (and the stamper) have a hologram area with MP
The optical disc 100 is manufactured by forming only the EG compressed data, and the hologram 101 is formed in an empty area on the optical disc 100.
May be formed.

Next, a hologram reproducing apparatus will be described with reference to FIG. The coherent light diffused and emitted from the laser light source 701 is focused by the collimating lens 702, and then the optical disk 1 is reflected by the half mirror 703.
It is reflected in the direction of 00. Then, the reflected light from the optical disk 100 passes through the half mirror 703 and is received by the two-dimensional image pickup device 704, whereby the optical disk 10
It is captured as a two-dimensional image represented by the hologram on 0.
It should be noted that such a hologram reproducing optical system can be configured integrally with a pickup for reproducing MPEG compressed data.

The present invention is not limited to a read-only optical disk, but can also be applied to a rewritable optical disk. When the laser beam is shifted in the track width direction when writing a hologram in a two-dimensional area, and when recording is performed on a land and a groove as in a phase-change optical disk, both the land and the groove are not deflected without deflecting the light beam. It may be recorded as one track. In this case, although the fineness of the interference fringes of the two-dimensional hologram is inferior, there is an advantage that the hologram can be rewritten by the pickup of the drive device.

[0029]

As described above, according to the present invention, a hologram is recorded by securing a two-dimensional area on the recording surface of an optical recording medium, and the content information is set so that the two-dimensional area becomes a user data area. Is variable-length encoded and recorded in another area, so that an information signal can be recorded on the recording surface of the optical recording medium using a hologram that is difficult to forge.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a variable length encoding device for realizing an embodiment of an information signal recording method and an optical recording medium according to the present invention.

FIG. 2 is a block diagram illustrating a decoding device.

FIG. 3 is an explanatory diagram showing a recording area of an optical disc.

FIG. 4 is an explanatory diagram showing a recording area of the hologram of FIG. 3;

FIG. 5 is an explanatory diagram showing a hologram.

FIG. 6 is a configuration diagram illustrating a recording apparatus.

FIG. 7 is a configuration diagram showing a hologram reproducing device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 optical disk 101 hologram A, B, C variable length coded data area a, b hologram area

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) G11B 7/24 522 G11B 7/24 522H F term (Reference) 2K008 AA04 BB04 BB05 HH01 5D029 JB01 JB42 VA08 WA09 WD10 5D090 AA01 BB04 CC01 DD03 DD05 EE02 FF09 GG02 GG36 HH01

Claims (2)

[Claims] 1. A hologram representing additional information is recorded in the two-dimensional area by securing a predetermined two-dimensional area extending over the plurality of tracks on an optical recording medium on which a spiral or concentric track is formed. And step of variable-length encoding the content information so that a user data area of content information to be recorded on the recording medium coincides with the two-dimensional area. Recording along a track. 2. A hologram representing an additional information signal is recorded in a predetermined two-dimensional area extending over the plurality of tracks on an optical recording medium on which a spiral or concentric track is formed, and a content information to be recorded is recorded. An optical recording medium in which the content information is variable-length coded so that a user data area matches the two-dimensional area and recorded along the track.