JPH09244520A - Image recording method and image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To record information with high density by hierarchically arranging plural two-dimensional plane images nearly in parallel in three-dimensional image space and holographically recording them. SOLUTION: Plural two-dimensional plane images 1A to 1E are hierarchically arranged in the three-dimensional image space and coherently illuminated with illuminating light 2 by the technique of holography, and then interference fringe by object light 3 and coherent reference light 4 is exposed and recorded on a recording medium 5. Since the images 1A to 1E are arranged at some intervals and the illuminating light is effectively enters between adjacent images, all the surface of each image is effectively illuminated. Therefore, the entire of each image is recorded. After the interference fringe is exposed on the recording medium 5, it is developed and fixed so as to form the hologram.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording method for holographically recording an image and an image reading device for reading an image from a hologram obtained by this image recording method.

[0002]

2. Description of the Related Art In holographic image recording / reproduction, reference light and object light are caused to interfere with each other, and the interference fringes are exposed and recorded on a recording medium, or interference is obtained by calculation using a computer generated hologram method. An image recorded as interference fringes is reproduced by recording the fringes on a recording medium to obtain a hologram and irradiating the hologram with reproduction light. In such holography, generally, an image of a three-dimensional object is recorded.

On the other hand, it is also known to encode numerical data and the like and record and display it as two-dimensional plane image information as represented by a bar code. Since such a coded two-dimensional plane image can be directly recorded and displayed on a medium by printing or the like, it is widely used as a method for easily displaying product information on a product package or the like. However, a coded two-dimensional plane image represented by a conventional barcode is recorded and displayed directly on a recording medium such as paper by a method such as printing, and the recorded content can be easily read, so that security is improved. There is a problem that necessary data cannot be handled, and since it is coded in a black and white striped pattern, it has a problem that the appearance is impaired when it is displayed on a package of a product.

As a solution to such a problem,
For example, in Japanese Unexamined Patent Publication No. 1-211088, a light / dark pattern corresponding to code data is recorded in a hologram, and the hologram is irradiated with laser light so that the reproduced light / dark pattern is received by a photoelectric conversion element. A code data system has been proposed.

[0005]

However, in the case of recording a three-dimensional image on a hologram, when the image is read using a reading optical system, the depth of the object is within the depth of field of the reading optical system. If not, there is a problem that the image cannot be read accurately. Further, Japanese Patent Laid-Open No.
In the code data system disclosed in Japanese Patent No. 211088, since the bright and dark pattern corresponding to the code data is recorded on the hologram as a single two-dimensional plane image, the three-dimensional image is originally recorded. There is a problem that the features of reproducible holography cannot be fully utilized and high-density information recording cannot be expected.

A first object of the present invention is to provide an image recording method capable of recording information at a high density in view of the above problems.

Further, a second object of the present invention is to provide an image reading apparatus appropriately configured so that the information recorded on the hologram by the above image recording method can be accurately read.

[0008]

In order to achieve the first object, in the image recording method of the present invention, a plurality of two-dimensional plane images are hierarchically arranged substantially parallel to each other in a three-dimensional image space. The holographic recording is performed on the recording medium.

Further, in order to achieve the second object,
The present invention is a device for reading a image from a hologram recorded holographically by hierarchically arranging a plurality of two-dimensional plane images substantially parallel to each other in a three-dimensional image space, wherein the hologram is read at a predetermined angle. An illumination system for coherent illumination or incoherent illumination, a two-dimensional image reading means for reading one reproduced two-dimensional plane image from a plurality of reproduced two-dimensional plane images, and a reproduction two-dimensional image read by the two-dimensional image reading means. An image selecting unit for selecting a plane image is provided.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the image recording method of the present invention, since a plurality of two-dimensional plane images are hierarchically arranged substantially parallel to each other in a three-dimensional image space, all the two-dimensional plane images are illuminated with illumination light. Irradiation is possible and therefore high density recording is possible. Further, in this way, when a plurality of two-dimensional plane images are holographically recorded on a recording medium, at the time of reproduction, the plurality of recorded two-dimensional plane images are three-dimensionally without intersecting with each other. Since they are reproduced, each reproduced two-dimensional plane image has position information and parallax. Therefore, it becomes possible to change the focus adjustment and the reading angle at the time of reading, and moreover, since each reproduced image is a two-dimensional plane image and is well within the depth of field of the reading optical system, the conventional plane image reading device It is possible to easily and accurately read a desired reproduced two-dimensional plane image without being disturbed by another reproduced two-dimensional plane image.

Further, in the image reading apparatus of the present invention, when the hologram is illuminated by the illumination system, that is, when the hologram is irradiated with reproduction light, the image recorded in the hologram is reproduced. Here, since a plurality of two-dimensional plane images are holographically recorded hierarchically arranged in parallel in a three-dimensional image space in the hologram, these reproduced two-dimensional plane images are
It will be reproduced three-dimensionally without crossing each other. One of the reproduced plurality of reproduced two-dimensional plane images is selected by the image selecting means, and the selected one reproduced two-dimensional plane image is read by the two-dimensional image reading means. Therefore, each reproduced two-dimensional plane image can be accurately read.

[0012]

1 is a diagram for explaining a first embodiment of the present invention. In this embodiment, a plurality of two-dimensional plane images 1A to 1E are hierarchically arranged substantially parallel to each other in a three-dimensional image space, and these two-dimensional plane images 1A to 1E are illuminated by an illuminating light 2 by a known holography technique. Coherent illumination is performed, and interference fringes formed by the object light 3 and the coherent reference light 4 are exposed and recorded on the recording medium 5. Here, the two-dimensional plane images 1A to 1E are arranged at a certain interval,
Since the illumination light effectively enters between adjacent images, the entire surface of each image can be effectively illuminated, and thus the entire screen of each image can be recorded. After the recording medium 5 is exposed with the interference fringes, it is developed and fixed to form a hologram.

As shown in FIG. 2, the hologram created in this way is recorded on the hologram 7 by irradiating the hologram 7 with coherent reproduction light 8 from the irradiation direction of the reference light at the time of recording. Image reproduction Two-dimensional plane images 1a to 1e can be obtained. Play 2 here
The three-dimensional image planes 1a to 1e are hierarchically arranged in a three-dimensional image space so as to be superimposed substantially parallel to each other and reproduced with position information and parallax without intersecting each other. Is possible. Moreover, since each reproduced image is a two-dimensional plane image and falls within the depth of field of the reading optical system, for example, the entire desired reproduced two-dimensional plane image can be obtained by a conventional image reading device having a lens and a CCD. It is possible to easily separate and read the images without being disturbed by other reproduced two-dimensional plane images.

FIG. 3 is a diagram for explaining the second embodiment of the present invention. In this embodiment, a plurality of two-dimensional plane images 11A to 11D are hierarchically arranged substantially parallel to each other in a three-dimensional image space so as to be overlapped when viewed from the reading direction, and recorded on a recording medium 12 by a known holographic technique. Then create a hologram. Here, as each two-dimensional plane image, for example, an image formed by the opaque scattering material 14 on the transparent sheet 13 is used. Therefore, the plurality of two-dimensional images 11A-1
Even if the 1Ds are overlapped with each other when viewed from the reading direction, the light flux emitted from the rear two-dimensional plane image passes through the front transparent sheet portion, so that the rear two-dimensional plane image can be surely recorded.

The hologram thus created is
As shown in FIG. 4, the hologram 15 is irradiated with the coherent reproduction light 16 from the irradiation direction of the reference light at the time of recording to reproduce the plurality of recorded images.
The three-dimensional plane images 11a to 11d can be obtained. Here, the reproduced two-dimensional plane images 11a to 11d are reproduced in an overlapping manner when viewed from the reading direction, but each image is composed of the transparent portion 13a and the opaque scattering portion 14a,
Also, due to the parallax of the holographic three-dimensional image, the reproduction 2
By changing the reading angle with respect to the three-dimensional plane images 11a to 11d, it is possible to change the overlapping position of the reproduced image on the front side and the reproduced image on the back side, so that each reproduced image can be reliably read.

FIG. 5 is a diagram for explaining the third embodiment of the present invention. In this embodiment, as in the case of the second embodiment, a plurality of two-dimensional plane images 21A to 21D are hierarchically arranged substantially parallel to each other in the three-dimensional image space so as to be overlapped when viewed from the reading direction. A hologram is created by recording on the recording medium 22 by a known holography technique. In this embodiment, each image is composed of a transparent portion 23 having a predetermined width and an opaque scattering portion 24. Therefore, also in this case, since the light flux emitted from the rear two-dimensional plane image passes through the front transparent portion 23, the rear two-dimensional plane image can be surely recorded.

The hologram thus created is
As shown in FIG. 6, the hologram 25 is irradiated with the coherent reproduction light 26 from the irradiation direction of the reference light at the time of recording to reproduce the plurality of recorded images.
The three-dimensional plane images 21a to 21d can be obtained. Here, the reproduced two-dimensional plane images 21a to 21d are reproduced in an overlapping manner when viewed from the reading direction. However, as in the case of the second embodiment, each reproduced image is composed of the transparent portion 23a and the opaque scattering portion 24a. In addition, due to the parallax of the holographic three-dimensional image, the reproduced two-dimensional plane images 21a to 21a.
By changing the reading angle with respect to 21d, it is possible to change the overlapping position of the reproduced image on the front side and the reproduced image on the rear side, so that each reproduced image can be reliably read.

In the third embodiment, the interval Dn between adjacent images of a plurality of superposed two-dimensional plane images 21A to 21D is the width a of the transparent portion 23 of the two-dimensional plane image as shown in FIG. And the width b of the opaque scattering portion 24 and the interval D1 between the two-dimensional planar images 21A and 21B are determined arbitrarily,

[Equation 1] It is desirable to decide so as to satisfy the relationship.

According to the image recording method of the present invention illustrated in the above-mentioned first to third embodiments, a plurality of two-dimensional plane images are holographically recorded by hierarchically arranging them in parallel in a three-dimensional image space. Therefore, particularly when recording a pattern in which a two-dimensional image is encoded, for example, a barcode, it is possible to record a plurality of barcodes in which various information is encoded. The recording is excellent and the appearance can be recorded beautifully, and the above-mentioned conventional problems can be effectively solved.

FIG. 8 shows a fourth embodiment of the present invention. This example is recorded in hologram 31 and 3
The reproduced two-dimensional plane images 32a, 32b, 32c that are reproduced so as to be superimposed substantially parallel to each other in the three-dimensional image space are read as virtual images. The hologram 31 is coherently illuminated from a predetermined angle by a semiconductor laser 33 and an illumination lens 34, and an image reproduced by the hologram 31 is imaged on an image sensor (CCD) 37 via a bandpass filter 35 and an imaging lens 36. I will let you. As the bandpass filter 35, one having a peak transmittance in the wavelength of the illumination light is used. The CCD 37 is three-dimensionally, that is, front and rear, with respect to the hologram 31 by the arm 38.
Supports the position adjustment vertically and horizontally.

In such an image reading apparatus, the distance of the CCD 37 from the hologram 31 is made constant or variable by the arm 38, and the focus is adjusted by the imaging lens 36, so that the reproduced two-dimensional plane images 32a, 32b ,.
From 32c, an arbitrary image can be read after being scaled to an arbitrary magnification. In addition, the CCD 38 by the arm 38
By moving up and down, left and right and changing the reading angle, the image on the back surface can be read by parallax. In addition, the image formed on the CCD 37 is reproduced by the bandpass filter 35 having a peak transmittance at the wavelength of the illumination light, because noise light due to light having a wavelength other than the desired reproduced image is effectively removed. The S / N of the image can be improved.

FIG. 9 is a diagram for explaining the fifth embodiment of the present invention. In this embodiment, a laser beam 42 is made incident from the back surface of a hologram 41 in which a plurality of two-dimensional plane images are recorded so as to be superimposed in a reproduced three-dimensional image space substantially in parallel, and one of the diffracted light beams 43a and 43b is made. CCD
The light is received by 44 and the real image is read. The CCD 44 is supported by the arm 45 so that its position can be adjusted in the front-rear direction with respect to the hologram 41. Also, CC
Around the D44, a light shielding means 47 for shielding the 0th-order light 46 which is not diffracted by the hologram 41 is provided, and a shutter 48 for allowing only a desired reproduced two-dimensional plane image to enter the CCD 44 is movably provided. .

In such an image reading apparatus, the laser beam 42 is obliquely incident on the hologram 41, and the shutter 48 is appropriately moved, whereby the hologram 4 is recorded.
A desired reproduced two-dimensional plane image can be selected from a plurality of reproduced two-dimensional plane images reproduced from No. 1 and read by the CCD 44. In this embodiment, since the reproduced two-dimensional plane image is read as a real image, the imaging lens is not always necessary, but the imaging lens is arranged between the hologram 41 and the CCD 44 to obtain a desired reproduced two-dimensional plane image. It is, of course, possible to read at a desired magnification.

FIGS. 10A, B and C show a sixth embodiment of the present invention.
It is a figure for explaining an example. In this embodiment, reproduced two-dimensional plane images 52a, 5a recorded on a hologram 51 and reproduced so as to be superimposed in a three-dimensional image space substantially in parallel.
2b and 52c are passed through a confocal optical system having a lens 53 and a pinhole 54, and a CCD 55 is formed by an imaging lens 55.
The image is selectively formed on 56 and read.

That is, when reading the reproduced two-dimensional plane image 52a, as shown in FIG. 10A, the position of the lens 53 is adjusted so that the light ray 57 from the reproduced two-dimensional plane image 52a is focused on the pinhole 54. Then, the light ray 57 passing through the pinhole 54 is imaged on the CCD 56 by the imaging lens 55. In this case, the light ray 58 from the reproduced two-dimensional plane image 52b and the light ray 59 from the reproduced two-dimensional plane image 52c hardly pass through the pinhole 54,
Be shielded.

Similarly, when the reproduced two-dimensional plane image 52b is read, as shown in FIG. 10B, the position of the lens 53 is adjusted so that the light ray 58 from the reproduced two-dimensional plane image 52b is focused on the pinhole 54. When reading the reproduced two-dimensional plane image 52c, the lens 53 is adjusted in position so that the light ray 59 from the reproduced two-dimensional plane image 52c is condensed on the pinhole 54, as shown in FIG. 10C. ,
The light rays passing through the respective pinholes 54 are imaged on the CCD 56 by the imaging lens 55.

According to this embodiment, since the confocal optical system having the lens 53 and the pinhole 54 is used,
Only the reproduction light from the desired reproduction two-dimensional plane image is transferred to CCD5
You can lead to 6. Therefore, the S / N of the reproduced image
Can be improved.

In the above-described embodiment, when reading a plurality of reproduced two-dimensional plane images reproduced from the hologram, the end of reading one reproduced image is detected, and the next reproduced image is selected and read. In addition, it is possible to automatically select and read a plurality of reproduced two-dimensional plane images. Further, in the above embodiments, the example of the Fresnel hologram reproduced by the coherent reproduction light is shown, but a Lippmann type hologram using incoherent light such as white light as the reproduction light of the hologram may be used.

Appendix 1. The image recording method according to claim 1, wherein each of the plurality of two-dimensional planar images has a transparent portion and an opaque scattering portion. 2. The image recording method according to claim 1, wherein each of the plurality of two-dimensional planar images has a transparent portion of a predetermined size. 3. The image reading apparatus according to claim 2, further comprising a reading angle changing unit that changes a reading angle with respect to the hologram. 4. The image reading device according to claim 2, wherein
The image reading device, wherein the three-dimensional image reading means has a confocal optical system. 5. The image reading device according to claim 2, claim 3 or claim 4, wherein the two-dimensional image reading means has an imaging optical system. 6. The image reading apparatus according to any one of claims 2 and 3 to 5, wherein the two-dimensional image reading unit includes a bandpass filter having a peak transmittance at a wavelength of illumination light. apparatus. 7. The image reading device according to claim 2 or any one of claims 4 to 6, further comprising a holding device that holds the two-dimensional image reading device at a predetermined position with respect to the hologram. 8. The image reading device according to any one of claims 2 and 3 to 7, wherein the completion of reading of one reproduced two-dimensional plane image by the two-dimensional image reading means is detected,
An image reading apparatus characterized in that selection of a reproduction two-dimensional plane image by the image selecting means is switched to the next reproduction two-dimensional plane image, and a plurality of reproduction two-dimensional plane images are automatically read sequentially.

According to the image recording method of the additional item 1, since each two-dimensional plane image is composed of the transparent portion and the opaque scattering portion, even if the images are arranged to overlap each other, the rear surface The light emitted from the two-dimensional plane image can be reliably recorded through the transparent portion of the front two-dimensional plane image. Also, when reproducing the hologram recorded in this manner, similarly, the light emitted from the reproduced two-dimensional plane image on the back surface passes through the transparent portion of the reproduced two-dimensional plane image on the front surface, so that it is surely read. be able to.

According to the image recording method described in appendix 2, since each two-dimensional plane image has a transparent portion of a predetermined size, even if the images are arranged so as to overlap each other, a three-dimensional image by holography is obtained. If the angle with respect to the front image is changed by changing the angle with respect to the two-dimensional plane image due to the parallax, the light flux emitted from the back two-dimensional plane image can pass through the transparent portion of the front surface. It is possible to reliably record the entire surface of the planar image. Also, when the hologram recorded in this way is reproduced, the hologram can be surely read in the same manner.

According to the image reading apparatus described in appendix 3, the reading angle changing means can change the reading angle with respect to the hologram, so that the reproduced two-dimensional plane image on the back surface can be read by parallax.

According to the image reading device of the additional item 4, since the two-dimensional image reading means has the confocal optical system, the reproduction light from the reproduction two-dimensional plane image before and after the desired reproduction two-dimensional plane image is effective. Therefore, the S / N ratio of the read image can be improved.

According to the image reading apparatus described in appendix 5, since the two-dimensional image reading means has the image forming optical system, only a desired reproduced two-dimensional plane image is formed on the image forming surface by the image forming action. The image can be read by changing the magnification and forming an image. Further, if the imaging optical system is used, the reproduced secondary planar original image can be read as a virtual image.

According to the image reading apparatus described in appendix 6, since the two-dimensional image reading means has the bandpass filter having the peak transmittance in the wavelength of the illumination light, noise light other than the light used for reading is effective. Therefore, the S / N ratio of the reproduced two-dimensional plane image can be improved.

According to the image reading apparatus described in appendix 7, since the holding means can hold the two-dimensional image reading means at a predetermined position with respect to the hologram, a plurality of reproduced two-dimensional plane images can be read. The position becomes constant, so that the desired reproduced two-dimensional plane image can be easily selected.

According to the image reading apparatus described in appendix 8, since a plurality of reproduced two-dimensional plane images are automatically read sequentially, these reproduced images can be read substantially simultaneously and efficiently.

[0038]

According to the image recording method of the present invention, a plurality of two-dimensional plane images are hierarchically arranged substantially parallel to each other in a three-dimensional image space and are holographically recorded on a recording medium. Therefore, information can be recorded with high density.

Further, according to the image reading apparatus of the present invention, the desired reproduction 2 is performed from a plurality of reproduction 2D plane images recorded on the hologram and reproduced so as to be superimposed in substantially parallel to each other in the reproduction 3D image space. Since the two-dimensional plane image is selected by the image selection means and read by the two-dimensional image reading means, each reproduced two-dimensional plane image can be accurately read.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a method of reproducing a hologram created by applying the recording method of the first embodiment.

FIG. 3 is a diagram for explaining a second embodiment of the present invention.

FIG. 4 is a diagram for explaining a method of reproducing a hologram created by applying the recording method of the second embodiment.

FIG. 5 is a diagram for explaining a third embodiment of the present invention.

FIG. 6 is a diagram for explaining a method of reproducing a hologram created by applying the recording method of the third embodiment.

FIG. 7 is a diagram for explaining a method of setting adjacent image intervals of a plurality of two-dimensional plane images to be recorded in a superimposed manner in the third embodiment.

FIG. 8 is a diagram showing a fourth embodiment of the present invention.

FIG. 9 is also a diagram for explaining the fifth embodiment.

FIG. 10 is also a diagram for explaining the sixth embodiment.

[Explanation of symbols]

1A to 1E, 11A to 11D, 21A to 21D Two-dimensional plane image 1a to 1e, 11a to 11d, 21a to 21d Reproduction 2
Dimensional plane image 2 Illumination light 3 Object light 4 Reference light 5, 12, 22 Recording medium 7, 15, 25 Hologram 8, 16, 26 Reproduction light 13 Transparent sheet 14 Opaque scattering material 13a, 23, 23a Transparent part 14a, 24, 24a Opaque scattering part 31,41,51 Hologram 32a-32c, 52a-52c Reconstructed two-dimensional plane image 33 Semiconductor laser 34 Illumination lens 35 Bandpass filter 36,55 Imaging lens 37,44,56 Imaging device (CCD) 38, 45 arm 42 laser light 43a, 43b diffracted light 46 0th order light 47 light shielding means 48 shutter 53 lens 54 pinhole 57, 58, 59 rays

Claims (2)

[Claims] 1. An image recording method, comprising: arranging a plurality of two-dimensional plane images hierarchically in a three-dimensional image space in a substantially parallel manner and recording them holographically on a recording medium. 2. A device for reading a hologram from a hologram recorded holographically by hierarchically arranging a plurality of two-dimensional plane images substantially parallel to each other in a three-dimensional image space, wherein the hologram has a predetermined angle. Illumination system for coherent illumination or incoherent illumination, and one reproduction from a plurality of two-dimensional plane images to be reproduced.
An image reading apparatus comprising: a two-dimensional image reading means for reading a two-dimensional plane image; and an image selecting means for selecting a reproduced two-dimensional plane image read by the two-dimensional image reading means.