Universal digital holographic printer and method

The present invention relates to holography, and more particularly to a method and apparatus for recording and printing holographic composite images based on digital information.

For more than fifty years, holograms have been made based on the following general principle: the object is illuminated by a coherent beam of light, the diffused light of the object falls on a carrier covered with high-resolution

A capacity photoemulsion that is simultaneously illuminated by a coherent support beam. (See, for example, ENLeith et al., "The Reconstructed Theory of Communication and Communication," Journal of the Optical Society of America, 53,1377-81, 1963).

However, to capture a holographic image of this object using this method, it is necessary to have a real physical object. Usually, the size of the holographic image is exactly the size of a real physical object. In many cases, the practical application of this method is unacceptable.

For many years, an alternative method of retrieving information and then directly recording an interference pattern to characterize a hologram has been discussed and explored (see U.S. Patent No. 4,701,006). However, today, even with the help of a modern arsenal of computing, calculating the interference model from Fourier transforms is a difficult task. Moreover, even with the necessary calculations, it is very difficult and expensive to record these models. The preferred technology for this purpose is video recording using an electron beam.

Another method of producing holograms that does not require a real object has been proposed by King et al. (Applied Optics, 1970). In this work, it has been shown that holograms can be created by optically juxtaposing information from multiple two-dimensional images captured by the same camera. The importance of this idea lies in the fact that the device that prints the final hologram can be distinguished from the real object, and the holographic image of the object does not necessarily have to match the actual object's dimensions. It was later shown that the real object may not be needed at all if the two-dimensional images of the object are generated only as computer information (see U.S. Patent No. 3,843,225).

Typically, the above principle is implemented when many conventional and sequential images of a subject are sequentially recorded by a camera that moves along a straight or circular track. Each resulting image is then used in a specific optical system that overlaps and combines the information to form an intermediate (or H1) hologram as disclosed in U.S. Pat. 3,832,027. From such a hologram, the holographic image may already be transferred to another hologram, which will now be visible in white light, known as the hologram H2. To accomplish this, the hologram H1 is illuminated with a laser beam by the principle of interconnected geometry, and the resulting image is then used as an object for the hologram H2. Illuminating this H2 hologram with a composite support beam reconstructs the true image of the subject in white light (see MV Grichine, DBRatcliffe, GR Skokov, "An Integrated Pulsed-Holography System for Mastering and Transferring onto AGFA or VR-P Emulsions" Proc. SPIE Vol. 3358, p. 203-210, Sixth International Symposium on Visual Holography, Tung H. Jeong; Ed.).

An alternative scheme is described in U.S. Pat. 4,206,965, which shows how the images taken are grouped together in a final, white light hologram of many tiny hologram strips folded sideways, thus eliminating the need for an intermediate H1 hologram. Subsequently, U.S. Patent 4,498,740 describes a two-dimensional composite hologram recording system, each consisting of a two-dimensional grid of individual holograms. Each such hologram corresponds to a specific point on the object. However, the disadvantage of the latter system is that it requires the subject to be very close to the recording material. Furthermore, the present invention does not allow the creation of holograms that adequately reconstruct the directional properties of the light emitted from each image point.

U.S. Pat. 4,421,380 describes a novel system for producing panchromatic light-transmitting holograms using three overlapping holograms consisting of achromatic-type dot or dashed holograms, with a precise application of a color filter photo frame. U.S. Pat. No. 4,778,262 describes a method for directly recording a two-dimensional array of key holograms using computer information. The ideas of the latter patent were later developed in U.S. Pat. No. 4,969,700; 5,138,471, which describes similar technologies utilizing a one-dimensional spatial light beam modulator connected to a computer thereby directly recording conventional types of holograms as a two-dimensional array of basic holograms.

In U.S. Patent No. 4,834,476, we find another similar method that relies on computed or sequential camera data used to directly record Alcove composite holograms. They have reflection or transmission geometry, but this technology can be generalized to more conventional flat hologram production.

U.S. Pat. No. 4,964,684 discloses the use of a spatial beam modulator for solving a vibration problem in a holographic printer producing an intermediate hologram H1 based on computer or camera data. U.S. Pat. 5,949,559 describes how to directly record a better quality holographic stereogram while avoiding optical noise by changing the positions of various diffuse screens.

European Patent Application EP0816952A3 describes a technology for achieving a higher quality of composite holograms by using a photo template image instead of a real photo template, which, in many previous inventions, needs to be placed on the surface of a recording medium. Japanese patent no. JP11084992A describes a vibration damping system that reduces the effect of vibrations in a holographic printing system, thereby improving the quality of the holographic image. U.S. Pat. 5,973,807 discloses a technology for producing complex holographic stereograms using data from a camera or a computer to produce a set of H1 holograms. They are then copied through a special transfer process to form a larger composite hologram.

In many cases, producing an intermediate hologram H1 using information from a computer and further copying it or other image plane transfer techniques used to obtain a white hologram is superior to the direct method of recording the final hologram. This is for several reasons. This is primarily because it is often desired to produce holograms of limited parallax that only have horizontal parallax. In the case of technology using the H1 intermediate hologram, this hologram is usually made up of one or more holographic strips of overlapping holographic pixels. The classical optical transfer method then solves the problem of the computer-aided computational distribution of light over the entire two-dimensional surface of the final hologram.

If the final hologram is recorded live, then these calculations have to be made by computer. Also, for large holograms, the time it takes to record a two-dimensional holographic pixel matrix is ​​usually equal to the time it takes to write the H1 Master hologram squared, which in some cases is extremely long. Finally, it is often complained that live composite holograms appear to be "pixelated", whereas H1 Master holograms appear to be much less common. However, despite the disadvantages mentioned above, there are many cases where direct recording of the final hologram takes great advantage. This way, the holograms recorded directly are much easier to fit together to produce extra-large images. In most cases, a quick preview of the final hologram is required in advance. Therefore, it is not very convenient to produce the H1 hologram, then transfer it to another device and make the final hologram. In addition, live hologram recording technology allows the creation of holograms, hybrids that have very unconventional viewing angles, which is particularly attractive to the printing industry by adapting the holograms thus recorded to the installation of holographic billboards. An additional advantage of the direct recording method is its application to materials such as photopolymers (see. European Patent EP0697631B1), which requires dry chemical treatment, while classically producing H2 replicas of holograms, requires much more sensitive silver halides to be subjected to the classical development process.

The present invention relates to a method and apparatus for both directly recording the final composite holographic stereogram seen in white light and recording the H1 Master hologram, which could be used to produce a holographic stereogram visible in white light by classical imaging.

Another object of the present invention is to substantially address the vibration sensitivity of the environment and equipment in a holographic printer using a pulsed laser with appropriate time and space light beam characteristics such that the hologram recording time is limited to the time required to reproduce the image produced by the spatial fiber modulator.

Still another object of the present invention is the use of a combination of a spatial beam modulator and a wide angle lens with minimized aberrations and having a beam of light passing through it, while adjusting the spatial coherence of the laser beam passing through the aforementioned optical elements. optical patch noise when recording the H1 Master hologram without using diffusion screens, which have traditionally been ₆ EN 4842 B apply.

Another object of the present invention is the use of a combination of a spatial beam modulator and a wide angle lens with minimized aberrations and having a beam of light passing through it, while adjusting the spatial coherence of the laser beam passing through the aforementioned optical elements)>

method, avoiding significant optical patch noise by recording a composite hologram that may or may not be visible in white light. In such a composite hologram, the pixel size of each individual complementary hologram is adjustable to such a spatial coherence that allows the light intensity to be maximally distributed within the pixel.

Yet another object of the present invention is to displace a three-dimensional beam modulator representing a single pixel of each holographic image in one or two directions in the light input lens area of ​​said lens between laser flashes, thereby achieving higher resolution images in H1 Master holograms.

It is also an object of the present invention to synchronize the vertical and horizontal movement of the holographic material and the spatial beam modulator so that the pixels of the H2 image plane in the spatial beam modulator are aligned in the H1 hologram made of two-dimensional images such that when the H1 hologram is a defined "pixelated" image would be created on said H2 hologram surface. The images on the spatial beam modulator display can then be re-compiled and encoded into overlapping pixel groups representing multiple primary colors and then a color laminated or printed photo frame can be fitted to said H2 hologram to create a multicolour hologram.

Finally, the object of the present invention is the free movement of an element controlling spatial coherence, or defined by an algorithm that defines and controls the density of holographic pixels, thereby smoothing and reducing structure or spatial noise generated by the use of this element, and eliminating any other similar optical noises occurring in the system.

In all cases, the data for the hologram recordings are generated using a computer-based 3D model or derived from multiple images captured by a moving camera. Holograms are recorded using a laser beam on a suitable material on a recording head using a space modulator connected to a computer. Moves either recording material or a spatial modulator in one-dimensional or two-dimensional space to record a matrix or sequence containing a large number of pixels.

The invention is explained in the drawings, wherein:

FIG. illustrates a flow chart of sequentially captured camera images that can be used to produce holograms. This diagram also shows a computer model of an object when a point on the viewing plane determines the perspective from which the object's images are derived.

FIG. illustrates a top plan view of an optical device according to the invention.

FIG. illustrates the main selected components of the device according to the invention shown in perspective.

FIG. Shows the operation of the device according to the invention when in H1 Master Hologram Recording mode while recording an H1 throughput hologram.

FIG. illustrates the operation of the device according to the invention in the H1 hologram recording mode when the holographic material on which the recording is made is tilted at an achromatic angle.

FIG. depicts a device according to the invention in H1 hologram recording mode for recording an H1 reflection type hologram.

FIG. depicts a device according to the invention in live recording mode, recording a reflection-type hologram.

8a. depicts the overlapping structure of the subject's light beam, embedded in the holographic material that is characteristic of the H1 Master hologram, which is recorded to create a rainbow hologram by conventional transfer. Each circle contains information about the perspective corresponding to a particular viewing point.

8b. illustrates the overlapping density of an object's light beam

Composition I recorded on the holographic material that is characteristic of the H1 Master hologram, to create a panchromatic light rainbow hologram by conventional transfer. Each ellipse contains information about a perspective corresponding to a particular viewing point. The three rows of ellipses represent the distinction between the three primary colors.

FIG. illustrates the overlapping object fiber density structure recorded on the holographic material, typical of the H1 full aperture Master hologram for creating a rainbow achromatic hologram or a monochrome or panchromatic reflection hologram by a conventional transfer. Each circle contains information about the perspective corresponding to a given point in space, as shown in Figure 1.

FIG. shows the structure of the subject's fiber density recorded on the holographic material, which is typical of directly recorded holograms. Each circle contains information about the direction and amplitude of the light emitted, which forms a three-dimensional image.

Basic image data necessary for the invention.

The present invention generates an image of a 3D object from a computer using one of the standard commercial computer programs. Such computer programs nowadays allow for the creation of highly realistic digital models through a series of ancillary processes that mimic real effects. In addition, advances in computer technology have led to a significant reduction in the computational time required to run these programs. 3D image scanners, working on Moire or other principles, now allow real-world 3D images to be embedded in such computer models. The amount of computer memory required to store such 3D models largely depends on the texture descriptions used to create them, so computer files containing such 3D images are relatively small and can be easily transmitted over the Internet. Preferred embodiments of the present invention use such 3D computer-based digital models for generating two-dimensional camera images from a virtual viewing plane, as shown in Figure 1. Here 1 is the plane to be viewed. 2 and 3 are separate, two-dimensional computer generated images of the object 4. Such images come from many points in the viewing plane, e.g. 5 and 6. The spatial arrangement of such two-dimensional images and their density are usually controlled by the need for a particular type of hologram information. In one case they form a regular two-dimensional matrix, in another case they form a regular horizontal one-dimensional linear chain. Deviations from these regular shapes are useful for a number of reasons, such as the ability to reduce optical noise in the image while simultaneously controlling image blur.

Alternatively, the present invention may employ a realistic model instead of a digital one. Then a real camera is used, which captures individual photographs (either digitally or by using a film, which is then digitized). In this case, FIG. should be interpreted as follows: 4 represents the object to be holographic. 1 represents the plane containing the camera 5. Object 4 will be photographed from many points on that plane. For example, if the field of view is 5, the image in the image will be 2, if the field of view is 6, the resulting image will be 3. Usually, a certain mechanism is used to move the camera sequentially from one position to another. This can be done using a one-dimensional or two-dimensional stepping mechanism. As mentioned above, the spatial arrangement and density of two-dimensional images are usually controlled by the type of information required for a particular type of hologram, so that they form a regular two-dimensional matrix in one case and a regular horizontal one-dimensional linear chain in another. Deviations from these regular shapes are useful for many reasons. One of them is the ability to reduce optical noise in the image by controlling image blur.

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In both of these cases, the limited animation that can be transferred to the final hologram can be shaped such that the pattern 4 moves in a predetermined manner (implementing such animation) with different camera positions being selected, following sequential monotonic trajectories in said 1 plane. Looking at the final hologram, the viewer, following such a consistently monotone trajectory in the observation space, will perceive the animation.

The present invention is based on taking a series of two-dimensional, real or computer generated object, images, digitally processing them into digital information, and displaying them in the form of two-dimensional images on a spatial beam modulator. In a preferred embodiment of the present invention, such a spatial fiber modulator is a high-resolution liquid crystal display, but any other two-dimensional spatial fiber modulator having appropriate characteristics may be used.

In a preferred embodiment of the present invention, a pulsed laser is used to illuminate this three-dimensional fiber modulator. Such a pulsed laser may have one or more wavelengths and pulse duration characteristics ranging from a few nanoseconds to tens of microseconds. The frequency of such a laser pulse should ideally be close to the refresh rate of the selected spatial beam modulator. The use of a pulsed laser allows the construction of a commercial device that will not be exposed to vibrations. Therefore, such a device will be able to produce high-quality holograms quickly and with predictable results. The temporal coherence and pulse energy variation of such a laser must be chosen with great care. Typically, if the shoulders of the objective and support beam are aligned, the required temporal coherence is approximately a few centimeters. The final choice of pulse duration will depend on the holographic material used for recording. If necessary, pulse sequences may be used to extend the pulse envelopes of the fibers to maintain the peak peak power of the luminous pulses required for nonlinear changing of the beam frequencies.

A special lighting system is used to regulate the spatial coherence of the laser beam. In a preferred embodiment, the telescope and microlens array are used for this purpose. However, there are many other suitable systems for controlling the spatial coherence of laser beams that can replace the latter without changing the spirit of the invention. Such systems are characterized as systems that control the spatial coherence of laser beams without causing significant optical noise.

The laser beam passes through a three-dimensional modulator and passes through a special wide-angle lens which focuses said beam into a narrow fold outside this lens, forming a beam known as an objective beam. The spatial beam modulator image is formed at a certain, adjustable distance from said junction.

The hologram for recording a hologram is placed near or at the narrowest point of the objective beam of light. The support beam, which is coherent with this objective beam, illuminates the same area of ​​the holographic recording material, but at a different angle, so that the support and objective beam light interferes with each other to form an interference image that is recorded on the holographic recording material.

In one embodiment of the present invention, the holographic material moves in one-dimensional or two-dimensional space relative to the objective light beam so as to provide optimum overlap between the objective and support light beams, while the image in the surround beam modulator is altered such that each adjacent pair of objective and support beams the recording material would record an interference image corresponding to the corresponding digital data. A pair of objective and support light beams can also move while the recording material remains motionless. In either case, this technique allows the creation of individual interfering images (known as holographic pixels) that form a two-dimensional array or one or more one-dimensional linear chains of such pixels. A set of such pixels is called a composite hologram.

A very important feature of the present invention is that the size and intensity distribution of the objective and support light beams are carefully controlled depending on the type of hologram being recorded and the characteristics required for such a hologram. The objective beam control is performed by adjusting the spatial coherence of the laser beam. In the case of a support beam, this is done by a telescope, placing the aperture image projection on the recording material.

Another equally important feature of the present invention is that the wide-angle lens is constructed to minimize aberrations and maintain the narrowest point of the beam of light outside the lens.

Once recorded, such composite holograms are processed according to the requirements of the specific material on which they are inscribed to form a hologram. Preferred materials are photopolymers and silver halides, but other materials may be used without altering the spirit of the invention.

With the proper selection of information processing algorithms, many types of holograms can be produced using this method.

We can divide the holograms into two major classes of holograms. The first class includes holograms H1, which are created to be later transferred to another hologram (hereinafter referred to as the hologram H2). In this case, the 3D image plane is resized. Such image plane displacement described above is a standard classic hologram recording method. The second class of holograms consists of holograms that directly mimic this already-displaced image plane, or in other words * the holgram H2, avoiding the need for an intermediate step (H1 hologram). In this case, the 3D image plane is replaced by a computer that performs a different algorithm of mathematical manipulation with the set of primary data.

An important feature of the present invention is that it is possible to achieve optimal hologram quality by producing holograms of both of these classes, despite the fact that the two different classes of holograms require completely different recording conditions for the holograms. H1 holograms are of the highest quality when captured in large pixels that can occupy hundreds of times the area of ​​pixels needed to directly record the final hologram on the holographic recorder. These large pixels are overlapping. This produces an H1 hologram with a lower luminance but a significantly lower level of optical noise. An image plane transfer technique is then applied, which compensates for the lack of luminance by diffraction productivity. The result is an optimally bright, very high quality final H2 hologram.

Live recording holograms require intertwined pixel structures with minimal overlap to avoid loss of hologram luminance. In some cases, this places some restrictions on the quality of the final image.

The following is a preferred embodiment of the present invention which describes and illustrates the principles of operation and use of the present invention. However, it is very clear that those skilled in the art of holography may make various modifications, additions, and simplifications while maintaining the spirit and scope of the present invention. For example, the optical system can be arranged in various ways. The system for modulating the movement of the holographic writing material with respect to the spatial beam modulator may also be modeled in various ways, and instead of the flexible holographic tape, a solid base of the holographic material may be used, as described below.

FIG. Figure 4 is a top view of a preferred embodiment of the present invention. The single color, single longitudinal mode pulsed laser, marked 7, has a high working repetition rate and sufficient temporal coherence. It emits a beam of coherent light which is divisible by a variable fiber divider 8. The beam 9 travels to an optical mirror 10 which directs the latter to the optical mirror 11. This mirror deflects the beam of light into a wave plate 12 which controls the polarization of the beam. The beam of light then passes through the telescope lenses 13 and 14. The lens 14 is mounted on a stepping mechanism 15 having a motor marked 16. Thus, the fiber diameter of the optical lens 14 exiting is adjustable. The fiber passes through a microlens array 17 which expands the fiber onto a spherical collimating lens 18. The distance between the optical elements 17 and 18 is selected to correspond to the focal length of the lens 18. In this way, the collimated fiber exits the optical lens 18 with adjusted spatial coherence. Further, the beam illuminates the liquid crystal display (SKD) 19, which is mounted on a motor two-dimensional stepping mechanism 20 with a vertical control motor 21 and a horizontal control motor 22. Positions 23 and 24 show the maximum horizontal displacement of the SKD. The position of the SKD is adjusted during the recording of H1 type holograms to obtain a much higher final image resolution that cannot be achieved with the same, but static, SKD from a given viewing angle. Passing through a liquid crystal display, a beam of adjustable coherence light crosses a linear polarizer, which converts an SKD image from circularly polarized to amplitude modulated. The beam then passes through a wide-angle lens 25 attached to a motor stepping mechanism 26, which has a motor marked 27. This shifting mechanism is used to adjust the SKD image plane designed by the lens.

25th The size of the objective beam beam 28 is adjustable by a motor stepping mechanism 15 having a motor marked 16. Further, the objective beam falls on the holographic material.

29th Here is how the holographic bar is mounted on the rotating step system. The motor 30 controls the movement of step step 31 towards and away from the objective beam of light beam. Shafts 32 and 33 control the horizontal movement of the holographic strip 29 relative to the objective light beam. The motor 34 controls the vertical movement of the holographic tape with respect to said objective light beam. The movement of shafts 32 and 33 is controlled by motor 35. Rollers 36 and 37 tension the holographic bar and adjust the horizontal angle at which the bar moves relative to the objective beam's axial propagation vector. For example, Figure 5 shows a portion of this diagram depicting a case where the holographic bar is retracted at an achromatic angle useful for recording H1 Master holograms, from which the image will later be transferred to panchromatic rainbow H2 holograms.

The shoulder of the support beam is separated from the main laser beam by a heated divider 8. The beam 38 is directed to a mirror 39 which reflects and deflects through an elliptical aperture 40. The image is finally created at the intersection of the support beam and the holographic recording material. , is defined as a circular or elliptical abutment in the recording material, depending on the requirements of the type of hologram being recorded. Further, the support beam travels to the waveguide plate 41, which controls the polarization of the laser beam. Optical elements 42 and 43 form a telescope that regulates the beam size, the latter being passed through an element 43 that is adjustable by a motor stepper 44 having an engine 45. Optical path 48 is used to create transmitting holograms, while path 47 is used to create reflection holograms.

In the case where the support beam is guided through the optical path 48 and passes through the lens 49, this lens projects an aperture 40 image on the surface of the recording medium. This lens also adjusts the small fiber umbrella that occurs when the fiber passes through the 43 lens. The fiber split, after 49 lenses, is ideally collimated and therefore adjustable within diffraction limits. In fact, this means that if the backing beam is small, it will not collimate very accurately, but the collimation error has far less effect on the image blurring than the size of the illumination source of the final hologram. Mirrors 50 and 51 direct the support beam to its final target, the intersection of the support beam with the objective light beam on the surface of the holographic recording medium. The motor rotary stepping mechanisms 52 and 53 with the motors marked 54 and 55, in combination with the linear stepping mechanism 56 with the motor 57, ensure that different angles of the support beam can be used at different positions of the recording material. The Bruster angle is generally used, but in certain embodiments of the invention, the angle is variable.

In the case that the support beam is guided through the optical path 47 and passes through the lens 58, this lens projects an aperture 40 image on the surface of the recording medium. This lens also adjusts the small fiber umbrella that occurs when the fiber passes through the 43 lens. The fiber split after 58 lenses is ideally collimated, so adjustable within the diffraction range as described₁₇ LT 4842 B above. Mirrors 59 and 60 direct the support beam to its end target at the intersection of the support beam with the objective light beam on the surface of the holographic recording material, in this case, the opposite. The motor rotary stepping mechanism with motor 61 and the linear stepping mechanism 62 with motor 63 ensure that different bearing angles can be used at different positions of the recording material. The Bruster angle is generally used, but in certain embodiments of the invention, the angle is variable.

Figure 2 is a perspective view of the main selected components of the present invention, the numbering of which corresponds to the numbering of the components of Figure 2.

To date, the most common type of H1 hologram is the H1 permeable hologram. These types of holograms are divided into four main types: 1) H1, suitable for production of rainbow permeable holograms; 2) H1, suitable for production of panchromatic rainbow permeable holograms; 3) H1 suitable for production of achromatic permeable holograms; 4) H1, suitable for producing monochrome permeable holograms. In all of the above cases, the individual holographic pixels must overlap well and be much larger than the objective beam fold to distribute some perspective information within the macroscopic hologram area and to ensure holographic averaging of system optical noises.

Figure 1 depicts how the system operates during the recording of the H1 transmissive hologram. It should be noted here that the support beam reaches the holographic recording material on the same side as the objective beam, forming a pixel 28. It is noteworthy that said pixel is far from the point of convergence 64. It is also noticeable that the image being projected from SKD 19, is at a distance 65 from the recording medium 29. The screen, placed in plane 66, will see each of the highly focused two-dimensional images loaded on the SKD 19. The plane 66 generally corresponds to the H2 plane of the hologram in terms of image transfer geometry.

To capture the H1 transmissive hologram, the perspective images of a real or computer-generated object are pre-distorted to compensate for the remains of optical aberrations, and to adjust to a particular end-of-light illumination geometry. These images are then loaded one after the other onto the SKD, a holographic pixel is recorded, the recording material is rotated, and this process is repeated for each image. In the first case, the top row of pixels is recorded in the holographic recording material as shown in Figure 8a. Each circle represents an interfering image that has information about a given image from a perspective point of view, viewed along a horizontal direction. Figure 8b depicts the second case where three rows of pixels are recorded at an achromatic angle and each row corresponds to a red, green, or blue composite image seen in the final hologram, depending on the axial viewing position. Such a holographic image recording geometry is illustrated in the second case in Figure 5. Figure 9 shows the third and fourth cases in which a two-dimensional pixel matrix is ​​to be recorded. In the third case, all horizontal pixel rows actually contain recorded information associated with a single vertical parallax. In the fourth case, there may be, but not necessarily. However, with full parallax, pixel density can be modulated to optimize optical noise by averaging, thereby reducing the chromatic blur of each individual image due to the adjacent pixel, resulting in the clarity of the individual image. Typically, this is taken into account when producing large-format full parallax reflection-type holograms, which have the chromatic aberration problem of using an infinite number of images to produce a stereogram. In addition, very large format, reduced parallax holograms can be produced for optimum results, provided that fading and optical noise are carefully controlled.

In all cases, the spatial coherence of the objective beam must be adjusted so that the size of the objective beam fold 28 outside the lens 25 is also adjusted accordingly. This pinch also saves the image from blurring, resulting in better image quality. If the creek is too small, the image quality will be poor, if the creek is too wide, the image will be dim. However, the range of suitable joint sizes between the extremes of these parameters is very large, so it is extremely important to carefully choose the optimal size of the joint 28.

The final optimum pixel density maximum for the H1 transmissive hologram should be determined by the characteristics of the holographic material used for recording. In certain embodiments of the present invention, such as panchromatic holography, it is preferable to select an H1 reflection hologram rather than an H1 transmissive hologram. In this case, a single-frequency monochrome laser would need to be replaced by a multicolored single-frequency laser and the SKD or other spatial fiber modulator should be replaced by a colored SKD or other spatial fiber modulator. In this case, the color H1 hologram can be recorded using the geometry shown in Figure 6. The final reflection H2 hologram can then be made from the latter by transferring the image plane. The pixel density on such H1 reflection holograms may differ slightly from the pixel density required for H1-permeable holograms, depending on the characteristics of the available holographic recording material.

When the hologram is recorded live, the luminance of the final hologram by moving the image plane is no longer controlled. Therefore, the hologram recorded should be of optimum luminance immediately. This means that the holographic pixels must be more closely aligned than overlapping, as shown in Figure 10. It follows that the optimum position of the holographic tape for recording will be at the location of the objective fiber fold, as shown in Figure 7. The object beam fiber spatial coherence adjustment system described above is now used to control the size of holographic pixels and to ensure that their intensity distribution on the surface of the holographic recording material is close to the Gaussian distribution.

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For direct hologram insertion, perspective images of a real or computer object are mathematically transformed, thereby creating a new set of images that are then pre-distorted to compensate for optical aberration residues, as well as due to the applicable final illumination geometry . Such images are then loaded onto the SKD, the holographic pixel is recorded with the SKD image plane optimally set to the desired viewing plane, or infinitely, and then the recording material is rotated and the process repeated. The process is executed in such a way as to create a two-dimensional holographic pixel array in which each pixel accurately reproduces a beam of light passing through a given point in the selected image plane as it passes through a real or virtual computer-generated object. To a certain degree, the hologram thus created is identical to the hologram produced as the H1 hologram, and then the hologram H2 is produced in the classical image plane displacement. However, when applied in practice, these two methods are very different but complementary and, as mentioned above, they both have their advantages in individual cases.

Different mathematical transformations can be accomplished to create holograms of all major types using the direct hologram recording method. Rainbow holograms can be constructed so that the individual SKD image files for that holographic pixel consist of a single horizontal information bar. The height of this bar on the SKD is selected to depend on the vertical position of the holographic pixel. This creates a hologram that focuses the light that illuminates it on the horizontal bar in front of the hologram. This tape is modulated by visual information from a single vertical perspective, thereby creating a rainbow hologram. In the case of creating a tricolor rainbow hologram, the image files will consist of three horizontal stripes for each holographic pixel, the vertical position of which on the SKD will vary depending on the vertical position of the corresponding holographic pixel. As a result, the final hologram focuses its illuminating light on three parallel horizontal bars in front of the hologram, only this time the three bars are in a plane inclined achromatically with respect to the normal hologram normal vector. In addition, each bar is modulated with the corresponding primary color image information from a single vertical perspective, thereby creating a panchromatic rainbow hologram. The achromatic permeable hologram is created from SKD image files consisting of vertical bars, horizontally modulated with horizontal perspective visual information. Full parallax reflection holograms are also created by transforming SKD image files in a two-dimensional manner.

Varying mathematical transformations, it is possible to create hybrid type holograms by direct recording so that from a single point of view achromatic image can be seen while from another point the image can acquire rainbow characteristics. As an alternative, it is easy to create many different viewing "windows" for holograms. By controlling parameters, such as blur, it is possible to create holograms with very high depth of field when viewed from certain angles, while other viewing angles can be optimally adapted to reveal the integrity of the image with closer objects.

Frequently, certain methods of adjusting the spatial coherence of the objective light beam produce noise in the object beam. The most common pattern is laser blur. This is avoided by the present invention since only devices for adjusting spatial coherence are used which do not cause any significant optical patches. In a preferred embodiment of the present invention, a telescope and a microlens array are used to achieve such control. However, the physical construction of microlenses tends to bring some optical structure into the objective fiber. This noise can be significantly reduced by moving the microlens matrix in a free or defined manner during each exposure (illumination). Such optical noise can be significantly reduced by selecting the optimum maximum pixel density as described above.

when recording H1 holograms, the SKD is moved both horizontally and vertically within the lens's introductory lens, with consistent recording operations, allowing efficient use of a smaller SKD, which would otherwise be much larger, to obtain the same viewing angle and resolution in the final H2 hologram. If we are producing the H1 hologram to create the final rainbow hologram, the SKD only moves in one direction. However, if we produce H1 holograms for tricolor rainbow holograms or full parallax H1 holograms, the SKD is moved in a two-dimensional fashion.

The vertical and horizontal movements of the holographic material and the spatial light modulator are synchronized so that the pixels of the H2 image plane in the spatial beam modulator are aligned in the H1 hologram made of two-dimensional images such that a defined "pixelated" image is created on the surface of said H2 hologram. The images on the surround beam modulator display can then be re-compiled and encoded into overlapping pixel groups representing multiple primary colors, which can then be matched to the said H2 hologram to produce a color, laminated, or printed photo frame to create a multicolour H2 hologram.