KR100261623B1 - Method for controlling reproducing of recorded data in volume holographic digital storage/reproducing system - Google Patents

Abstract

PURPOSE: A method for controlling volume holographic digital storage and reproduction of a reproduction system is provided to store reference information for setting zero point angle to guarantee compatibility. CONSTITUTION: The method for controlling volume holographic digital storage and reproduction of the reproduction system is performed as follows. At first, a divided signal light and a signal light modulated with a stored reference data are generated, and the modulated signal light and a reference light having a predetermined deflection angle are interfered to store the reference data on a reference data when the system is set to be a record mode(208). Deflection angles are allocated for each data under a predetermined superstition schedule until all hologram data are recorded(210). Then, the record mode is turned off(218). Divided reference angle is reflected with an arbitrary deflection angle and is directed to be incident on the storage medium so as to restore the arbitrary data when the system is set to be a reproduction mode(216). Then whether the restored output is same to the predetermined reference data. The forth and fifth steps are repeated when the restored output is not same to the predetermined reference data. At last, the deflection angle is allocated to a reproduced restored output as the zero point angle and the hologram data stored on the recording medium is reproduced.

Description

How to control playback of volume holographic digital storage and playback system

The present invention relates to a volume holographic digital data storage and reproducing system, and more particularly, to the reproduction of data with compatibility between respective holographic digital storage and reproducing systems for any storage medium. A playback control method of a volume holographic digital storage and playback system suitable for carrying out the present invention.

Recently, the field of technology using volume holographic digital data storage is being actively researched everywhere due to the remarkable development of semiconductor laser, charge coupled device (CCD), liquid crystal display (LCD), etc. As a result of this research, fingerprint recognition systems for storing and reproducing fingerprints have been put to practical use, and are being expanded to various fields that can apply the advantages of large capacity and ultra-fast data transfer rate.

The volume holographic digital storage and reproducing system as described above is a storage medium, for example, optical refraction, in which an interference fringe generated when the signal light from the object and the reference light interfere with each other is sensitive to the amplitude of the interference fringe. By recording to a storage medium such as a sex crystal, the intensity and phase of the signal light are also recorded by a method of changing the angle of the reference light or the like, so that a three-dimensional image of an object can be displayed, and pages of binary data can be displayed. Hundreds to thousands of holograms organized in units can be stored in the same place.

On the other hand, a typical volume holographic digital storage and reproducing system, in recording mode in which the hologram data is recorded, splits the laser light generated from the light source into the reference light and the signal light, and the signal light is shaded according to the external input data. Modulated with binary data, an interference fringe obtained by interfering with the recording reference light reflecting the modulated signal light and the branched reference light at a predetermined deflection angle is recorded in the storage medium as hologram data corresponding to the input data.

At this time, the hologram data is superimposed (multiplexed) when recorded on the storage medium, so that the data is recorded on the storage medium while deflecting the reference light according to the angle overlap schedule promised to each other based on the reference angle, which is the zero angle. As the recording method, there are methods such as angular superposition, wavelength superposition, and phase code superposition, for example.

Further, the volume holographic digital storage and reproducing system, in the reproducing mode, blocks the signal light branched from the laser light generated from the light source, and irradiates the storage medium with the reproducing reference light for deflecting the branched reference light at a predetermined reproduction angle. Then, the interference fringe recorded through this irradiation diffracts the reference light for reproduction to demodulate one page of binary data composed of the original pixel contrast, thereby reproducing the desired specific hologram data.

At this time, the reproducing operation deflects the reproducing reference lights according to the mutually agreed angle overlapping schedule with respect to the reference angle which is the zero angle, so that the hologram data recorded on the storage medium is sequentially reproduced. The reproduction reference light used to reproduce the data recorded on the storage medium is a reference light having substantially the same angle as the reference light applied when recording the hologram data on the storage medium.

On the other hand, volume holographic digital storage and playback systems need to be compatible with each other, such as video cassette tapes can be played on any VCR set, given user convenience and efficiency. In order to be compatible with such systems, a function of matching the zero angle (absolute reference) of the reference light at the time of recording and the zero point (absolute reference) of the reference light at the time of reproduction between the systems is required.

That is, when the storage medium recording the hologram data in the system A is to be reproduced in the system B, the system B matches the zero angle (reference angle) of the reference light of the hologram data recorded on the storage medium with the zero angle of the reference light for reproduction. In this way, the zero angle at the time of recording and the zero angle at the time of reproduction are the same to allow perfect data reproduction.

However, the conventional storage and reproducing system does not currently consider the zero angle matching technique for maintaining the reproducibility between the systems as described above.

Accordingly, the present invention has been made in view of the above-mentioned points, and the present invention provides a volume holographic digital storage capable of storing reference information for setting a zero angle in a storage medium and maintaining playback compatibility between systems based on the stored reference information. It is an object of the present invention to provide a regeneration control method of a regeneration system.

In order to achieve the above object, the present invention is characterized by diverging the laser light generated from the light source into the reference light and the signal light, reflecting the branched reference light at a predetermined predetermined deflection angle, and obtained by modulation between the branched signal light and the input data. A method of controlling reproduction in a volume holographic digital storage and reproduction system in which a target hologram data is recorded on a storage medium by interfering a modulated signal light and the deflected reference light, wherein the system is set to a recording mode according to a user operation. A first step of generating modulated signal light between the branched signal light and pre-stored reference data and interfering with the generated modulated light and a reference light having a predetermined deflection angle to record reference data on the storage medium; Performing a recording operation while allocating a deflection angle for each data according to a preset overlapping schedule until all the hologram data to be recorded on the storage medium is recorded; A third step of releasing a recording mode of the system when recording of hologram data to be recorded on the storage medium is completed; When the system is set to the reproduction mode according to a user's operation, the branched reference light is reflected at an arbitrary deflection angle to enter the storage medium, thereby reproducing any data recorded on the storage medium to restore the original signal before modulation. Fourth process; A fifth step of checking whether the restored reproduction output matches the predetermined reference data; A sixth step of allocating a new deflection angle based on a preset overlapping schedule if the restored reproduction output does not match the preset reference data and then repeatedly performing the fourth and fifth processes; And as a result of the check, if the restored reproduction output matches the preset reference data, set a deflection angle assigned to the restored reproduction output to a zero angle, and set the preset overlapping schedule on the basis of the set zero angle. Accordingly, the present invention provides a reproduction control method of a volume holographic digital storage and reproduction system comprising a seventh step of performing a reproduction operation of hologram data recorded on the storage medium.

1 is an overall schematic diagram of a typical volume holographic digital storage and regeneration system suitable for applying a regeneration control method according to the present invention;

2 is a flowchart illustrating a process of recording reference data and input data in a storage medium in a recording mode according to the control method of the present invention;

3 is a flowchart illustrating a process of setting a zero angle based on reference data recorded in a reproducing mode and performing a reproducing operation according to the set zero angle according to the control method of the present invention.

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

102: light source 104: optical separator

106,114 Shutter 108 Reference light lens system

110,118: reflector 112: actuator

116,122: signal light lens system 120: spatial light modulator

124: storage medium 126: output imaging lens system

128: CCD 130: output data processing block

132: system control block 134: memory block

The above and other objects and various advantages of the present invention will become more apparent from the preferred embodiments of the present invention described below with reference to the accompanying drawings by those skilled in the art.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 shows an overall schematic diagram of a typical volume holographic digital storage and reproduction system suitable for applying the reproduction control method according to the present invention.

As shown in the figure, the volume holographic digital storage and reproduction system includes a light source 102 for generating laser light required in holography and a storage medium 124 for storing three-dimensional hologram data (ie, interference fringes). And two paths including respective optical systems, that is, the reference light processing path PS1 and the signal light processing path PS2, are formed between the light source 102 and the storage medium 124.

Referring to FIG. 1, the optical splitter 104 splits laser light incident and generated from the light source 102 into a reference light and a signal light, wherein the divided reference light is provided to the reference light processing path PS1 and the branched signal light. Is provided to the signal light processing path PS2.

Next, on the reference light processing path PS1, a reflecting mirror 110 having a shutter 106, a reference light imaging lens system 108, and an actuator 112 is sequentially provided in the emission direction of the reference light, and the reference light processing having such an optical structure. In the path PS1, reference light required for recording or reproducing hologram data is generated and provided to the storage medium 124 at a predetermined predetermined deflection angle.

That is, the reference light branched from the optical separator 104 and incident through the opening of the shutter 106 is adjusted through the reference light imaging lens system 108 and then transmitted to the reflector 110, where the reference light imaging lens system 108 is For example, it may be configured using a waste construction lens, a beam expander, or the like.

On the other hand, the reflector 110 deflects the reference light provided from the reference light imaging lens 108 to a predetermined angle, for example, a recording angle during data recording or a predetermined reproduction angle for reproduction. The deflected reference light is incident on the storage medium 124.

In this case, the reference light used during recording or reproduction is controlled by rotating the reflector 110 to change its deflection angle θ each time binary data of each page unit is recorded. Hundreds to thousands of holograms can be stored or played back on the storage medium 124.

Here, the angle adjustment of the reflector 110 is performed by a motor driven by the actuator 112 based on the control from the system control block 132 described later, wherein the deflection angle θ of the reference light is It is adjusted through the measurement of an angle meter (eg encoder) attached to a predetermined portion.

On the other hand, on the signal light processing path PS2, the shutter 114, the first signal light imaging lens system 116, the reflector 118, the spatial light modulator 120, and the second reference light imaging lens system 122 are directed in the direction of the light emission. In order to record hologram data in sequence, one-by-page units of light and dark binary data forming pixels according to external input data applied to the spatial light modulator 120 from the system control block 132 described later. The modulated signal light is provided to the storage medium system 124. Here, the shutter 114 maintains an open or blocked state in accordance with a control signal from the system control block 132, which maintains an open state in the recording mode and a blocked state in the reproducing mode.

In this case, the first signal light imaging lens system 116 may be configured by a reimaging lens, a beam expander, or the like, and the second signal light imaging lens system 122 may be configured by using a field lens, a Fourier lens, or the like.

On the other hand, the spatial light modulator 120 modulates the signal light reflected by the reflector 118 in units of one page of binary data of light and shade of pixels according to data input from the system control block 132 which will be described later. That is, as an example, when the input data is image data in units of one frame of the image, the extended object light incident on the spatial light modulator 120 is modulated in units of one frame.

On the other hand, the storage medium 124 has, in the recording mode, the reflector 110 having a signal light modulated in units of pages of binary data provided from the second signal light lens system 122 and a deflection angle θ corresponding thereto. The interference fringe obtained through the interference between the recording reference light incident from the image is recorded. That is, the light induced phenomenon of the kinetic charge is generated in the storage medium 124 according to the intensity of the interference fringe obtained by the interference between the signal light and the reference light. Through this process, the three-dimensional hologram data is stored in the storage medium 124. Interference fringes are recorded.

Further, in the storage medium 124, in the reproducing mode, when the reproducing reference light is irradiated with the predetermined deflection angle θ from the reflecting mirror 110, the recorded interference fringe diffracts the reproducing reference light to produce the original pixel. It is demodulated into one page of binary data (that is, a checkered pattern) composed of light and dark.

Then, the three-dimensional hologram data demodulated in units of one page of binary data reproduced from the storage medium 124 is reimaged through the output reimaging lens system 126 and then irradiated to the CCD 128 so as to provide original data. Is restored. At this time, the reference light used to reproduce the hologram data recorded on the storage medium 124 is a reference light having substantially the same angle as the reference light applied when recording the hologram data on the storage medium 124.

Meanwhile, the output data processing block 130 performs signal processing such as error correction on the reproduction output provided from the CCD 128 and provides the signal to the system control block 132.

On the other hand, the system control block 132 includes, for example, a microprocessor to control various operations of the reproduction system, that is, operation control signals of the light source 102, control signals for opening and closing the shutters 106 and 114, and reflectors. The driving signal of the actuator 112 for rotating the 110, the control signal for the operation of the spatial light modulator 120, and the operation control signal of the CCD 128 are respectively generated to control various operations.

In addition, the system control block 132 controls the recording of the reference data for maintaining compatibility in the recording mode, scans the reference light for reproduction to the storage medium 124 in the reproducing mode, and records the recorded reference data in the storage medium 124. Detecting the output of the reference data, i.e., whether or not the reproduction output obtained at the time of the scan operation coincides with the reference data previously stored in the memory block 134, and when the reproduction output matching the reference data is detected, The playback angle is set to the zero angle (ie, the reference angle) of the storage medium 124, and then the normal playback mode is performed according to the promised schedule (ie, the angular overlap schedule) based on the set zero angle.

In this case, predetermined reference data is stored in the memory block 134. As the reference data, for example, a signal having a resolution determination image form may be used as in the VCR.

Next, a description will be given of the process in the process of performing the reproduction control according to the present invention using the storage and reproduction system having the above-described configuration.

2 is a flowchart illustrating a process of recording reference data and input data in a storage medium in the recording mode according to the control method of the present invention.

Referring to the figure, when the system is set to the recording mode according to the user's operation (step 202), the system control block 132 opens the two shutters 106 and 114 and simultaneously controls the laser light generation in the light source 102. (Step 204). In this case, the reflector 110 is set to a zero angle position according to the driving of the actuator 112 under the control of the system control block 132.

Accordingly, the reference light branched through the optical separator 104 is deflected through the reflector 110 at a predetermined zero angle (that is, the reference deflection angle) and is incident to the storage medium 124.

At the same time, the signal light branched from the optical separator 104 is incident to the spatial light modulator 120 through the reflector 118, and at this time, the system control block 132 extracts the reference data previously stored in the memory block 134, To light modulator 120 (step 206). Next, the spatial light modulator 120 generates a modulated signal light through modulation between the signal light and the input reference data, and the modulated signal light generated in this way is a reference light incident from the reflector 110 into the storage medium 124 (ie, The reference light having a zero angle) and enters the storage medium 124.

Accordingly, in the storage medium 124, an interference fringe corresponding to reference data having a predetermined zero angle (or reference angle) will be recorded through interference between the incident reference light and the modulated signal light (step 208). At this time, the reference data recorded on the storage medium 124 is for maintaining reproduction compatibility between the respective systems. When the storage medium 124 is reproduced by another system, the zero point at the time of recording using the reference data recorded by the other system is recorded. The regeneration zero angle (reference angle) corresponding to the angle is set.

Next, when reference data for reproduction compatibility is recorded as described above, the system control block 132 performs a normal recording mode to perform a recording operation on the external input data, that is, recording on each input data. The recording operation of the hologram data to be recorded is performed while controlling the deflection angle of the reference reference light according to the promised angle overlapping schedule (steps 210, 214, and 216).

The recording operation as described above is repeated until the recording of the data to be recorded is ended. If it is determined that the recording of the check result data in step 214 is completed, the system control block 132 records the recording that has been made so far. The mode is released and the system is set to standby mode (step 218).

Therefore, the recording operation of the hologram data to be recorded on the storage medium is completed at the same time as the recording of the reference data for maintaining the reproduction compatibility between the respective systems through the above-described process at the time of recording the data on the storage medium.

Next, a process of performing the playback mode by automatically setting the playback zero angle in the storage medium in which the reference data and the plurality of hologram data are recorded through the above-described process will be described.

3 is a flowchart illustrating a process of setting a zero angle based on reference data recorded in a reproduction mode according to the control method of the present invention, and performing a reproduction operation according to the set zero angle.

Referring to the figure, when the system is set to the playback mode according to a user's operation in a state in which a storage medium recording data from another system is seated in the system to play back data (step 302), the system control block 132 The reference light side shutter 106 is opened, the signal light side shutter 114 is blocked, and the laser light generation in the light source 102 is controlled (step 304).

At this time, the reflector 110 is set to an arbitrary deflection angle (any reproduction angle assigned to the promised angle overlapping schedule) according to the driving of the actuator 112 under the control of the system control block 132 (step 306). ).

Therefore, the reproduction reference light is incident on the storage medium 124 through the reflector 110 set at an arbitrary deflection angle, so that the reproduction output corresponding thereto is generated in the storage medium 124, and this reproduction output is the CCD 128. Is converted into an electrical signal and then restored to the system control block 132 via the output data processing block 130 (step 308).

On the other hand, the system control block 132 checks whether the restored playback output matches the reference data previously stored in the memory block 134 (step 310), and if the check result playback output does not match the previously stored reference data, Next, the reflector 110 is deflected to a predetermined and then refresh angle according to the promised angle overlapping schedule (step 312), and then the process proceeds to step 308 described above.

That is, the reference angle (ie, zero angle) of the recording angle is extracted through the reproduction angle scanning that repeats the above steps 308 to 312, that is, the reproduction output that matches the reference data preset through the reproduction angle scanning. Is detected, and the reproduction angle of the detected reproduction output when the reproduction output coincides with the reference data is set to the zero angle for reproduction (ie, the reference angle) of the storage medium (step 314).

Therefore, in the system control block 132, when the zero angle for reproduction is set, the sequential reproduction of the hologram data recorded in the storage medium 124 is performed while controlling the deflection angle with respect to the reflector 110 according to the promised angle overlapping schedule. The operation is performed (step 316).

Meanwhile, in the above-described embodiment of the present invention, the reference data set in the storage medium are recorded and the zero angle for reproduction is set based on the reference data at the time of reproduction. By making the reproduction output level of the normal hologram data larger, the zero angle setting for reproduction can be more surely realized.

Further, in the above-described embodiment of the present invention, the case of the angular overlapping recording method has been described as an example, but it should not be understood that the present invention is necessarily limited thereto. In other words, the present invention can be applied not only to the angular superposition recording method but also to any superposition recording method such as the wavelength superposition recording method and the phase code superposition recording method.

As described above, according to the present invention, reference data for reproduction compatibility is recorded on a storage medium at the time of data recording, and reference data recorded on the storage medium is extracted at the time of reproduction in a system, and the reproduction angle of the reference data is set to zero angle. By performing the regeneration mode in accordance with the promised angle superimposition schedule on the basis of the set zero angle, perfect reproduction compatibility between the respective systems can be realized.

Further, according to the present invention, by accurately matching the zero angles (reference angles) between the systems using reference data, a reproduction output having the maximum diffraction efficiency at the time of data reproduction can be obtained, and crosstalk noise by adjacent hologram data can be obtained. This can be suppressed as much as possible to minimize the bit error rate of the playback output.

Claims (4)

The laser light generated by the light source is split into the reference light and the signal light, and the reflected reference light is reflected at a predetermined deflection angle. The modulated signal light obtained by the modulation between the branched signal light and the input data is interfered with the deflected reference light. A method of controlling playback in a volume holographic digital storage and playback system for recording holographic data to a storage medium, the method comprising: When the system is set to the recording mode according to a user's operation, the modulated signal light is generated between the branched signal light and the previously stored reference data, and the interference is generated by interfering the generated modulated signal light with a reference light having a predetermined deflection angle. A first step of recording reference data on the medium; Performing a recording operation while allocating a deflection angle for each data according to a preset overlapping schedule until all the hologram data to be recorded on the storage medium is recorded; A third step of releasing a recording mode of the system when recording of hologram data to be recorded on the storage medium is completed; When the system is set to the reproduction mode according to a user's operation, the branched reference light is reflected at an arbitrary deflection angle to be incident on the storage medium to reproduce any data recorded on the storage medium and restore the original signal before modulation. Fourth process; A fifth step of checking whether the restored reproduction output matches the predetermined reference data; A sixth step of allocating a new deflection angle based on a preset overlapping schedule if the restored reproduction output does not match the preset reference data and then repeatedly performing the fourth and fifth processes; And As a result of the check, if the restored reproduction output coincides with the preset reference data, the deflection angle allocated to the restored reproduction output is set to a zero angle, and according to the preset overlapping schedule based on the set zero angle. A reproduction control method of a volume holographic digital storage and reproduction system comprising a seventh step of performing a reproduction operation of hologram data recorded on the storage medium. The method of claim 1, wherein the predetermined overlapping schedule is an angular overlapping schedule. The method of claim 1, wherein the predetermined overlapping schedule is a wavelength overlapping schedule. The method of claim 1, wherein the predetermined overlapping schedule is a phase code overlapping schedule.

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