KR100555964B1 - Holography data encoding/decoding method - Google Patents

Abstract

The present invention relates to a holographic data encoding / decoding method, wherein the disclosed encoding method encodes a total of C data bits of the digital input data into a total of G + G modulation bits, wherein the digital input data is C bits (where C = D + D + 1) blocking the data into groups and dividing the data into groups, specifying one bit as a reference bit among each block data divided into groups, and if the reference bit is "0", the preceding D bit is "1". Is converted into a type 1 G bit (where G = E + F, D < G) codes, in which the number of "E is E (where E ≠ F) (the number of" 0 "is F), and the trailing D bit Is converted to the second type G bit code in which the number of "1" is F (the number of "0" is E), and if the reference bit is "1", the preceding D bit is converted to the second type G bit. Converting the code, and converting the trailing D-bits to type 1 G-bit code, using a new double unbalanced code By encoding / decoding the graphic data, there is an advantage that the code rate is increased while the reproduction error rate is lowered.

Description

Holographic data encoding / decoding method {HOLOGRAPHY DATA ENCODING / DECODING METHOD}

1 is a block diagram of a holographic digital storage and reproduction system for performing a holographic data encoding / decoding method according to the present invention;

2 is a flowchart illustrating a holographic data encoding / decoding process according to the present invention.

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

110: storage and playback device 111: light source

112: optical separator 113, 116: shutter

114, 117: reflector 115: actuator

118: spatial light modulator 119: storage medium

120: CCD 130: data encoding device

150: data decoding device

The present invention relates to a holographic system, and more particularly to holographic data encoding / decoding suitable for encoding data for decoding holographic data on a storage medium or decoding data reproduced from a storage medium. It is about a method.

Currently, research and development of holographic recording media capable of storing hundreds to hundreds of Gbytes as optical storage media and their recording / reproducing apparatuses are being actively conducted for large-capacity and high-speed processing of data storage memories.

The recording of the holographic data is made by recording the intensity and direction of the signal light reflected from the object. The intensity and direction of the light of the object is composed of the interference of the signal light and the reference light to form an interference fringe, and the interference fringe is formed in a holographic storage medium made of a material that responds to the intensity of the interference fringe. The holographic data recorded on the storage medium can be read only by the reference light used in the recording process, and reference light having a different wavelength or phase from the reference light used during recording cannot be read through the holographic data recorded on the storage medium. .

By using this holographic property, it is possible to store a large amount of data inside a small recording medium by recording a lot of holographic data in the same place of the recording medium with different reference light.

A typical holographic digital storage and reproducing system splits a laser light generated from a light source into a reference light and a signal light in a recording mode in which holographic data is recorded on a storage medium, and splits the signal light into external input data (ie, input data to be stored). Holographic corresponding to the input data, the interference fringes obtained by modulating the pixel-contrast binary data of one page unit and interfering with the modulated signal light and the recording reference light reflected at a predetermined deflection angle. Record as data to storage media.

On the other hand, in the holographic digital storage and reproducing system, when the holographic data is recorded on the storage medium and reproduced, the holographic digital storage and reproducing system reproduces the reproduction signal by various factors such as the intensity of the laser light, distortion by the lens, scattering and diffraction in the system. Has a difference in intensity distribution as a whole.

In particular, the reference light irradiated to the storage medium for recording or reproducing has a Gaussian distribution characteristic. Due to this Gaussian distribution characteristic, the intensity of the reproduction signal is higher than a certain level in the center area of the reproduction signal, but the reproduction error rate is almost absent. There is a problem that the reproduction error rate is rapidly increased due to being below a predetermined level.

According to the prior art, there is a method of using a threshold as a method of decoding a reproduction signal, and there are a method of using a threshold or a method using a local threshold and a mean or 0.5 value of pixels. In the former case, if the average or the value of the pixel is larger than 0.5, it is read as 1, and if it is smaller, it is read as 0.

However, this method has a problem that it is difficult to apply in reality because the code rate is high but the reproduction error rate (particularly, the reproduction error rate at the corner of one page) is very high.

The latter method of using local thresholds divides the playback signal of one page into several regions, and applies different threshold values for each divided region, i.e., the closer the center of the page is, the higher the threshold value is. The farther away from the center of the page (ie, the closer to the edge), the 1 and 0 are determined by applying a relatively low threshold.

However, this method has the advantage that the code rate is high and the reproduction error rate is low, while the aspect of the noise pattern is different, the compatibility between the various systems is inferior. That is, each system has a different noise pattern according to the characteristics of the system and the surrounding environment. If the threshold values divided by the standardized standards are equally applied to the systems where the noise pattern is different from each other, the result is the same. As a result, the reproduction error rate inevitably increases, which causes a problem of increasing the reproduction error rate.

Another method for reducing the error rate of a reproduction signal is a method proposed by the Stanford University (hereinafter referred to as the Stanford method) in the United States. The Stanford method is a method in which input data is coded using a local value of 1 greater than zero. After the recording on the storage medium, and after the playback is reversed decoding. For example, 0 is coded as 01, 1 is coded as 10, recorded, and decoded after the reverse process.

However, in the case of the Stanford method, the playback error rate is lowered while the code rate (50%) is significantly lowered.

Another method for reducing the error rate of the reproduction signal is the method proposed by IBM (hereinafter referred to as the IBM method), which is coded so that the number of 1's and 0's is the same, recorded on a storage medium, and reproduced. After that, the decoding is done in the order of intensity.

8비트), 재생 시에는 재생된 신호 중(8비트 신호) 세기가 큰 것 4개를 1로, 나머지는 0으로 한 조합을 만들고 이를 6비트로 전환하여 디코딩하는 방식이다. 이러한 IBM 방식은 4 : 6에서 대략 67% 정도의 코드 레이트를 갖고, 6 : 8에서는 대략 75% 정도의 코드 레이트를 갖으며, 8 : 12에서는 대략 67% 정도의 코드 레이트를 갖는다.For example, for a 6: 8 code, 64 combinations of the same number of 1s and 0s of 8 bits are associated with 64 data (6 bits

8-bit), during reproduction, a combination of four of the reproduced signals (8-bit signal) having a greater intensity as 1 and the rest as 0 is converted to 6 bits and decoded. This IBM scheme has a code rate of about 67% at 4: 6, a code rate of about 75% at 6: 8, and a code rate of about 67% at 8:12.

However, the IBM method has the advantage of having a low reproduction error rate and at the same time has a relatively high code rate compared to the Stanford method, but still has a problem that the code rate is low to approach an ideal code rate (i.e., code rate 1).

In other words, the IBM method has a code rate of about 67% at 4: 6, a code rate of about 75% at 6: 8, and a code rate of about 67% at 8:12. However, such a code rate may never be sufficient to meet the utilization efficiency of the storage capacity.

The present invention has been proposed to solve such a conventional problem, and an object thereof is to provide a new dual unbalanced code and to reduce a reproduction error rate while increasing a code rate.                         

In one aspect of the present invention for realizing the above object, the holographic data encoding method is a method of coding a total of C data bits of digital input data into a total of G + G modulation bits, and converts the digital input data into C bits ( , C = D + D + 1), dividing the data into groups and dividing the data into groups, and specifying one bit as a reference bit among each block data divided into groups, and, if the reference bit is “0”, the preceding D bit. Is converted to a type 1 G bit (where G = E + F, D &lt; G) codes, in which the number of " 1 " is E (where E ≠ F) (the number of " 0 " is F) Converting the D bits into a second type G bit code having F number of "1" s (E number of "0" s), and if the reference bit is "1", converts the preceding D bits to the second type; Converting the G bit code, and converting the trailing D bit into a first type G bit code.

In another aspect of the present invention, a holographic data decoding method is a decoding method for recovering original data of D + D + 1 bits from reproduction data of G + G bits (where G = E + F, D &lt; G), Comparing the total light intensity of the preceding G-bit block with the total light intensity of the following G-bit block among the reproduction data of G + G bits, and setting the reference bit to "0" when the sum of the preceding G-bit blocks is smaller. If the sum of the preceding G-bit block is larger than the number of preceding G-bit blocks, the reference bit is recognized as "1", and each G-bit block is arranged according to the light intensity of the pixel. E pixels are assigned "1", F pixels are assigned "0", and then F pixels are assigned "1", and F pixels are assigned "0". Sequentially performing type 2 block decoding, and if the reference bit is "1", After performing type 2 block decoding, type 1 block decoding is sequentially performed, and information bits are removed for each G bit block and decoded into original D bit data to be used as reference bits and D + D bits. Outputting the restored data.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings. Through this embodiment, it is possible to better understand the objects, features and advantages of the present invention. However, the present invention is not limited to these examples.

1 is a block diagram of a holographic digital storage and reproducing system capable of performing the holographic data encoding / decoding method according to the present invention. 130 and the data decoding device 150.

The storage and reproducing apparatus 110 represents a general general reproducing system, and includes a light source 111 for generating laser light required by holography, and a storage medium 119 for storing three-dimensional holographic data (ie, interference fringes). (For example, a photorefractive crystal) and a CCD 120, and between the light source 111 and the storage medium 119 are two paths including a plurality of optical systems, that is, a reference light processing path PS1. And a signal light processing path PS2 are formed.

First, the optical splitter 112 splits the laser light incident from the light source 111 into a reference light and a signal light, where the reference light of the vertically polarized light is provided to the reference light processing path PS1 and the branched signal light is signal light processed. Provided by path PS2.

Next, the shutter 113, the reflector 114, and the actuator 115 are provided in the emission direction of the reference light on the reference light processing path PS1, and in the reference light processing path PS1 through the light transmission path, the holographic image is provided. The reference light necessary for recording or reproducing the data is reflected at a predetermined deflection angle and provided to the storage medium 119.

In this case, although not illustrated in FIG. 1 for convenience of explanation and improvement of understanding, a plurality of optical lenses (for example, a waist configuration lens, a beam expander, etc.) for reference light processing are provided on the reference light processing path PS1. do.

Accordingly, the vertically polarized reference light branched from the optical separator 112 and incident through the opening of the shutter 113 is adjusted through an optical lens or the like not shown and expanded to an arbitrary size (that is, the signal light processing path PS2 described later). ) To a size sufficient to cover the size of the signal light extending through the beam expander, and a preset reproduction for the predetermined angle, for example, the recording angle during recording or reproduction, through the reflector 114. After being deflected at an angle, it is incident (irradiated) onto the storage medium 119.

)를 변화시키는 방법으로 제어되는 데, 이러한 기준광 편향 기법을 통해 수백 내지 수천 개의 홀로그래픽 데이터를 저장매체(119)에 저장하거나 혹은 저장된 홀로그래픽 데이터를 재생할 수 있다.Here, the reference light used in recording or reproducing rotates the reflector 114 using the actuator 115 whenever the binary data of each page unit is recorded on the storage medium 119.

The reference light deflection technique may store hundreds to thousands of holographic data in the storage medium 119 or reproduce the stored holographic data.

On the other hand, the shutter 116, the reflector 117 and the spatial light modulator 118 are sequentially provided on the signal light processing path PS2 in the emission direction of the signal light, and the shutter 116 is controlled from the system control means (not shown). Therefore, the open state is maintained in the recording mode, and the cutoff state is maintained in the reproduction mode.

In this case, although not illustrated in FIG. 1 for convenience of explanation and improvement of understanding, a plurality of optical lenses (eg, reimaging lenses, beam expanders, field lenses, etc.) for signal light processing are provided on the signal light processing path PS2. ) Is provided.

Accordingly, the signal light branched from the optical separator 112 and incident through the opening of the shutter 116 is reflected at a predetermined deflection angle through the reflector 117 and then transmitted to the spatial light modulator 118.

Subsequently, in the spatial light modulator 118, the signal light transmitted from the reflector 117 is made of light and shade of pixels according to the input data (i.e., input data coded according to the present invention) provided from the data encoding apparatus 130. The signal light incident on the spatial light modulator 118 when the input data is image data in one frame unit of the image is modulated into signal light in one frame unit. The light is incident on the storage medium 119 in synchronization with the reference light incident from the reflector 114 of the path PS1.

)를 가지고 반사경(114)으로부터 입사되는 기록용 기준광간의 간섭을 통해 얻어지는 간섭 무늬가 기록된다. 즉, 변조된 신호광과 기준광간의 간섭에 의해 얻어지는 간섭 무늬의 강도에 따라 저장매체(119) 내부에서 운동 전하의 광 유도 현상이 발생하는 데, 이러한 과정을 통해 저장매체(119)에 홀로그래픽 데이터의 간섭 무늬가 기록된다.Therefore, in the storage medium 119, the signal light modulated in units of pages of binary data provided from the spatial light modulator 118 in the recording mode and the corresponding deflection angle (

The interference fringe obtained through the interference between the recording reference light incident from the reflecting mirror 114 with? That is, the light induced phenomenon of the kinetic charge is generated in the storage medium 119 according to the intensity of the interference fringe obtained by the interference between the modulated signal light and the reference light. Through this process, the holographic data is stored in the storage medium 119. Interference fringes are recorded.

Meanwhile, the data encoding apparatus 130 blocks the digital input data input from the outside (ie, input data to be recorded on the storage medium) in units of C bits (for example, 11 bits), and divides them into groups (S201 to S). S203) In this case, if one bit of each block data divided into groups is defined as a reference bit, and the reference bit is "0", the number of preceding D bits (for example, 5 bits) is equal to E (1). For example, the number 1 is converted to a type 1 G bit code of F ("0" is F), and the number of trailing D bits "F" is F (eg, 4) (" (S205 to S207). If the reference bit is "1", the preceding D bit is converted to the second type G bit code, and the trailing D bit. Of binary data consisting of block data obtained by converting a to a type 1 G bit code and coding a total of C data bits into a total of G + G modulation bits. Is transmitted to the spatial light modulator 118 (S205, S209).

Therefore, the spatial light modulator 118 irradiates the storage medium 119 with the signal light generated by modulating the signal light incident from the reflector 117 in units of one page of binary data composed of pixels. 119 stores holographic data coded according to the present invention.

On the other hand, when reproducing holographic data coded according to the present invention and recorded (stored) in the storage medium 119, the shutter 116 on the signal light processing path PS2 side under control from a system control means (not shown). Is in a blocked state and the shutter 113 is opened on the reference light processing path PS1 side.

Therefore, the reference light (reproducing reference light) branched from the optical separator 112 is reflected through the reflector 114 and irradiated to the storage medium 119. As a result, in the storage medium 134, interference recorded by the reference light for reading is obtained. The patterned reading reference light is diffracted and demodulated into one page of binary data (that is, a checkered pattern) composed of the original pixel contrast, where the demodulated reproduction signal is irradiated to the CCD 120.

Subsequently, the CCD 120 restores the reproduction output irradiated from the storage medium 119 to original data, that is, an electric signal, and the reproduced reproduction signal is transmitted to the data decoding apparatus 150 (S211).

The data decoding apparatus 150 decodes a coded reproduction signal reproduced from the storage medium 119 and output through the CCD 120 into an original signal before coding, and includes a preceding G bit (eg, G + G bits) of reproduction data. For example, the total of the light intensities of the 7-bit) block and the total light intensities of the following G-bit blocks are compared, and when the sum of the preceding G-bit blocks is smaller, the reference bit is recognized as "0" (S213 to S215). If the sum of the preceding G bit blocks is larger, the reference bits are recognized as "1" (S213 and S219). Each G-bit block is arranged in descending order according to the light intensity of the pixel. When the reference bit is "0", E pixels (for example, 3) are sequentially assigned "1" and then F ( For example, four pixels are subjected to the first type block decoding giving "0" followed by F pixels giving "1" and then E pixels giving "0". Decoding is performed sequentially (S217). In addition, when the reference bit is "1", F (for example, 4) pixels are assigned "1" sequentially, and E (for example, 3) pixels are assigned "0". After performing the second type block decoding, the E pixels are assigned "1", and the F pixels sequentially perform the first type block decoding giving "0" (S221). Then, by removing the information bits of H bits (for example, 2 bits) for each G bit block, decoding them into original D bits (for example, 5 bits) data, and outputting the data restored to the reference bits and D + D bits. (S223).

The inventors of the present invention have empirically embodied the process of coding holographic data, reproducing and decoding the coded data, and the implementation results are as follows.

Example 1

This embodiment is for a 5: 7 unbalanced code.

Block the digital input data into 11-bit units and divide them into groups.If one bit is set as a reference bit among each block data divided into groups, and if the reference bit is "0", the number of preceding 5 bits is "1". Is converted to the first type 7-bit code of which 3 is (4 "0" is number), and the second 5 bits of trailing 5 bits are "4" (3 "0" numbers). If the reference bit is "1", convert the preceding 5 bits into the type 2 7-bit code and convert the trailing 5 bits into the type 1 7-bit code. Is coded into a total of 14 modulation bits.

The 5-bit input data has 2 ⁵ = 32 combinations, and since the 7-bit code has ₇ C ₃ = 35 and ₇ C ₃ = 35 combinations, it can be seen that coding can be performed without difficulty.

Next, the decoding process compares the sum of the light intensities of the preceding 7-bit blocks and the sum of the light intensities of the following 7-bit blocks among the 14-bit reproduction data, and sets the reference bit to "0" when the sum of the preceding 7-bit blocks is smaller. If the sum of the preceding 7-bit block is larger, the reference bit is recognized as "1". Each 7-bit block is arranged in descending order according to the light intensity of the pixel. When the reference bit is "0", three pixels are sequentially assigned "1", and then four pixels are assigned "0". After the type block decoding, four pixels are assigned "1", and then three pixels are sequentially subjected to the second type block decoding giving "0". In addition, when the reference bit is "1", after performing the second type block decoding in which four pixels are assigned "1" sequentially and three pixels are assigned "0", three pixels are assigned "1". After provisioning, four pixels sequentially perform type 1 block decoding granting " 0 ". Each 7-bit block removes 2 bits of information bits, decodes the original 5-bit data, and outputs the data reconstructed into a reference bit and 10 bits (11 bits in total).

According to the first embodiment of the present invention as described above, the balance can be maintained by using an odd number of bits that cannot be implemented in the existing balanced code.

Example 2

This embodiment is for an 8:11 unbalanced code.

Block digital input data in 17 bit units and divide them into groups.If one bit is set as a reference bit among each block data divided into groups, and if the reference bit is "0", the number of preceding 8 bits is "1". Is converted to the first type 11-bit code having 4 (7 "0" s), and the second 8 bits of trailing 8 bits (7 "4" s) If the reference bit is "1", the preceding 8 bits are converted into the type 11 11-bit code, and the trailing 8 bits are converted to the type 1 11-bit code. Is coded into a total of 22 modulation bits.

The 8-bit input data has 2 ⁸ = 256 combinations, and since the 7-bit code has ₁₁ C ₄ = 330 and ₁₁ C ₇ = 330 combinations, it can be seen that coding can be performed without difficulty.

Next, the decoding process compares the sum of the light intensities of the preceding 11-bit blocks and the sum of the light intensities of the following 11-bit blocks among the 22-bit pieces of playback data, and sets the reference bit to "0 when the sum of the preceding 11-bit blocks is smaller. If the sum of the preceding 11-bit block is larger, the reference bit is recognized as "1". Each 11-bit block is arranged in descending order according to the light intensity of the pixel, and when the reference bit is "0", the first pixel to which four pixels are assigned "1" and seven pixels to "0" are sequentially assigned. After performing the type block decoding, seven pixels are assigned "1", and then four pixels sequentially perform the second type block decoding giving "0". In addition, when the reference bit is "1", seven pixels are sequentially assigned "1", four pixels are assigned "0", and then four pixels are assigned "1". After provisioning, seven pixels sequentially perform first type block decoding granting " 0 ". Each 11-bit block removes three bits of information bits, decodes the original 8-bit data, and outputs the data restored to the reference bits and 16 bits (17 bits in total).

According to the second embodiment of the present invention as described above, in the case of the existing 8:12 balanced code, 12 bits are used to represent 8 bits, but 11 bits may be implemented using the coding method of the present invention.

In addition, in the existing 8: 12 balanced code, six of 12 are selected, but in the second embodiment, four are selected, thereby reducing errors.

Although the foregoing description of the present invention has been described with reference to an embodiment, it is obvious that the technology of the present invention may be easily modified by those skilled in the art. Such modified embodiments should be included in the technical spirit described in the claims of the present invention.

As described above, the present invention has the effect of encoding / decoding holographic data using a new dual unbalanced code, thereby increasing the code rate and reducing the reproduction error rate.

Claims (6)

A method of coding a total of C data bits of digital input data into a total of G + G modulation bits, Dividing the digital input data into units of C bits (where C = D + D + 1) and separating the digital input data into groups; Determining 1 bit as a reference bit among the block data divided into the groups; In the case where the reference bit is "0", the first type G bit having the number of "1" s of the preceding D bits is E (where E ≠ F) (the number of "0" s is F), where G = Converting E + F, D &lt; G) codes, and converting the following D bits into a second type G bit code having F number of " 1 " (E number of " 0 &quot;); Converting the preceding D bit into the second type G bit code and converting the trailing D bit into the first type G bit code when the reference bit is "1". Holographic data encoding method comprising a. The method of claim 1, The encoding method blocks the digital input data into 11-bit units and divides the data into groups, and if the reference bit is "0" after setting one bit among the block data divided into the group as the reference bit, the preceding 5 The bit is converted into a first type 7 bit code in which the number of "1s" is three (the number of "0s" is four), and the trailing five bits are four in number of "1" (the number of "0" 3) second type 7 bit code, and if the reference bit is "1", converts the preceding 5 bits into the second type 7 bit code, and converts the following 5 bits into the first type 7 bit code. A holographic data encoding method comprising converting a total of 11 data bits into a total of 14 modulation bits by converting them into bit codes. The method of claim 1, In the encoding method, the digital input data is divided into groups by blocking the digital input data in 17-bit units, and if the reference bit is " 0 " The bit is converted into a type 1 11-bit code having 4 "1" s (7 "0" s), and the following 8 bits have 7 "1s" (the number of "0" s). 4) second type 11-bit code, if the reference bit is "1", converts the preceding 8-bit into the second-type 11-bit code, and converts the trailing 8-bit into the first type 11 A holographic data encoding method comprising converting a bit code into a total of 17 modulation bits into a total of 22 modulation bits. A decoding method for recovering original data of D + D + 1 bits from reproduction data of G + G bits (where G = E + F, D &lt; G), Comparing the total light intensity of the preceding G bit block and the total light intensity of the following G bit block among the G + G bits of reproduction data; If the sum of the preceding G bit blocks is smaller, the reference bit is recognized as "0". If the sum of the preceding G bit blocks is larger, the reference bit is recognized as "1" and then for each G bit block. Sorting according to the light intensity of the pixels, When the reference bit is "0", E pixels are sequentially assigned "1", and F pixels are "1", and then F pixels are "1" and F pixels are "1". And assigning E pixels sequentially to decode the second type block that gives &quot; 0 &quot; If the reference bit is "1", sequentially performing the second type block decoding, and then sequentially performing the first type block decoding; Removing the information bit for each G-bit block, decoding the original D-bit data, and outputting the data restored to the reference bit and the D + D bit. Holographic data decoding method comprising a. The method of claim 4, wherein The decoding method compares the total light intensity of the preceding 7-bit block and the total light intensity of the following 7-bit block among the 14-bit reproduction data to determine the reference bit when the sum of the preceding 7-bit blocks is smaller. 0 ", and if the sum of the preceding 7-bit blocks is larger, the reference bit is recognized as" 1 ", and the reference bit is" 0 "after sorting according to the light intensity of the pixel for each 7-bit block. "In this case, three pixels are sequentially assigned a" 1 ", four pixels are assigned a" 0 "type 1 block decoding, then four pixels are assigned a" 1 "and then three pixels Perform the second type block decoding which gives "0" sequentially, and if the reference bit is "1", perform the second type block decoding sequentially and then perform the first type block decoding sequentially, 2 bits of each 7-bit block Remove the security bit to decode the original 5-bit data of the reference bit and 10-bit graphic data decoding method alone, it characterized in that it outputs the restored data to the (11-bit). The method of claim 4, wherein The decoding method compares the sum of the light intensities of the preceding 11-bit blocks and the sum of the light intensities of the following 11-bit blocks among 22 bits of playback data, and sets the reference bit to "0" when the sum of the preceding 11-bit blocks is smaller. If the sum of the preceding 11-bit block is larger, the reference bit is recognized as "1", and the reference bit is "0" after sorting according to the light intensity of the pixel for each 11-bit block. In this case, four pixels are sequentially assigned "1", seven pixels are assigned "0", and then seven pixels are assigned "1", and four pixels are assigned "0". Performs a second type block decoding that gives ", and if the reference bit is " 1 &quot;, sequentially performs the second type block decoding and then sequentially performs the first type block decoding. 3 bits of information per 11-bit block Removed decodes the original 8-bit data of the reference bit and 16-bit graphic data decoding method alone, it characterized in that it outputs the restored data to the (17-bit) a.

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