The ICVision system is a diffractive display based on VLSI technology. It is designed to display holographic stereograms in real-time. The diffractive display is formed on the surface of standard integrated circuit chips which have been covered with a liquid crystal overlay. Fringing electrostatic fields generated by indium tin oxide electrodes on top of the integrated circuit are used to induce the actual diffractive display. Within the individual IC die making up the display will be computational engines that compute the image to be displayed. Because grating information is encoded in the ITO gratings at the time of chip fabrication, the actual real-time computation is several orders of magnitude less than previous approaches. A large display may be formed by a tessellation of several hundred IC die, each approximately 1 cm², on a flat substrate. An optical broadcast system would be used to transfer imagery information into the integrated circuits, obviating the need for wire bond attachments. This paper presents details of the overall architecture of the display system, and details of the holographic grating computations.

A 2D image can be scaled simply by changing its pixel size. If we were to apply this model to a hologram, it would cause distortion in the reconstructed 3D images, and a change in the viewing angle. We propose a method for scaling the reconstruction image without changing its fringe element, i.e., pixel size. We divide the hologram into small blocks. Then, these blocks are repositioned in order to magnify or demagnify the reconstructed image. This method maintains the viewing angle and causes no distortion. It does, however, blur the reconstructed image. To reduce the blur, we propose a method of interpolation in the frequency domain. Results of experiments performed on an electro-holography system are also presented.

This paper presents a new type of the interactive holography display system which features both dynamic and precisely detailed imaging. The main discussion is on synthesis of electronic holograms and optical holograms. Electronic holograms have benefits of dynamic imaging of computer generated 3D objects in essence. On the other hand, conventional optical holograms are known to be suitable for detailed and precise imaging. Considering that many images typically contain objects which dynamically move around on the still background, synthesis of electronic holograms and optical holograms has high potential that the currently limited electronic holograms are applied to a wide range of applications. The second discussion of this paper is about the possibility of producing computed holograms in real time. Computation time of generating holographic fringe patterns with a parallel computer CYBERFLOW is considerably reduced by using techniques such as parallel computation with and within 64 processing elements, vectorized computation, scalar computation simultaneously in parallel with vector computation, and simultaneous computation with data transfer to the output display device. The obtained result is 84.7 times as fast as a conventional computer and promises the possibility of the real time computer generated hologram.

Electro-holographic and volumetric displays are current subjects of research for the auto- stereoscopic presentation of multi-variate information in real-time. Although both technologies offer robust psychological and physiological depth cues, discrepancies limit their usefulness to specific applications. This paper presents a multi-dimensional display system which, in dual modes, functions as both a 360 degree(s) electro-holographic stereogram (also known as cylindrical or multiplex electro-hologram) and volumetric display. The system alternately provides both holographic and volumetric images, with corresponding depth cues, in one display space.

A 2D image can be scaled simply by changing its pixel size. If we were to apply this method to a hologram, it would cause distortion in the reconstructed 3D images, and a change in the viewing angle. We propose a method for scaling the reconstructed image without changing its fringe element, i.e., pixel size. We divide the hologram into small blocks. Then, these blocks are repositioned in order to magnify or demagnify the reconstructed image. This method maintains the viewing angle and causes no distortion. It does, however, blur the reconstructed image. To reduce the blur, we propose a method of interpolation in the frequency domain. Results of experiments performed on an electro-holography system are also presented.

An electronic analog to a multiplex hologram is described. The system is comprised of a CRT and a Spatial Light Modulator (SLM). The SLM is thin film ferroelectric ceramic based. The CRT displays an NTSC raster, the light from which is amplitude modulated as it passes through the SLM. Each electrode on the SLM is driven by a separate video signal generated by an x-axis array, or by a computer. This produces a spatially multiplexed array of video images which, when viewed at a normal distance from the SLM, appear as a composite image having true depth. Color operation is achieved by tripling the number of electrodes on the SLM, and then associating an RGB filter array with them. Each filter/electrode group is fed the appropriate primary color trio signal from a video camera in the x-axis fly's eye array. Methods of bandwidth conservation are discussed, including a 6 MHz configuration which still permits viewing in true 3D without glasses. A method for achieving projected image operation is presented. A thick panel design is described briefly. Possible applications for this technology are mentioned as are areas requiring further research.

Holographic movies can be seen as a tool to estimate the picture quality of moving holographic images as a step towards holographic television. The authors have previously developed two versions of an experimental holographic movie system, and this paper is a report on an improved version 3 of the system. The new version features a newly-developed recording system which utilizes a pulsed Nd:YAG laser with an injection seeder, and an automatic film driver unit which moves perforated 35 mm holographic film intermittently. The system is mounted on a dolly to which a hydraulic lifter is attached. A twin diamond-shaped hologram format, developed for an earlier version of the system, is adopted for the films. After the films are developed, they are driven intermittently with a shutter, illuminated by the LD pumped CW Nd:YAG laser, and viewed through twin diamond-shaped windows. This version 3 system makes it possible to record live scenes, including those of the human body, flowing liquids, smoke, etc., which was impossible in the version 1 and version 3 systems. As a consequence, the characteristics of holographic 3D images with motion can be studied over an area covered by both eyes, and the labor required of animators in taking holograms is greatly reduced.

A new method to record a color holographic stereogram and its application in the synthesis of a conical holographic stereogram are presented. The method consists in recording three rainbow holograms on each slit hologram. To obtain the three images reconstructed on the same place, the position of the projection screen is changed when recording the three rainbow holograms. The difference of the projected image's size that appears because of the movement of the screen, is corrected by introducing a cylindrical lens in the projection system. Results of the method, feasibility and distortion of the image are discussed.

Unlike holograms of real objects, holographic stereograms consist of information recorded from a relatively small number of discrete viewpoints. As discrete imaging systems, holographic stereograms are susceptible to aliasing artifacts caused by insufficient or improper sampling. A characterization of sampling-related image artifacts in holographic stereograms is presented. Constraints on image extent and resolution imposed by sampling are outlined. Methods of reducing or eliminating aliasing artifacts in both photographically-recorded and computer-generated holographic stereogram images are described. Results of this analysis can be generalized to describe other autostereoscopic displays.

We will report on the status of the development of the OFFICE HOLOPRINTER^TM. Last year we showed that we were able to make one-step holograms. This year we will show a new approach to quality one-step holograms and explain the practical and theoretical principles. This paper will also include new possibilities for holoprinter input.

A one step technique for color mixing rainbow `shadow' holograms is accomplished by a single exposure. Multiple slit beams are projected simultaneously onto a dual plane, variable angle diffusion screen, thus permitting a wide range of wavelength selection. The H1 is illuminated by a single white light point source and is analyzed in terms of the projected slit wavelength reconstructions.

Computer generated hologram (CGH) using the image processing system with large frame memory was constructed. The kinoform was used for on-axis CGH and it was displayed on the liquid crystal device (LCD) and the 3D animated image was reconstructed. Moreover the kinoform with arrayed LCD display system was constructed and characteristics of superimposed image was considered and also characteristics of the color animated image was considered.

Color holography is typically achieved through the use of three wavelengths during the imaging. However, three-color holography is sufficient only when one has the freedom to select locally the proportions of the primaries during reconstruction. This freedom exists in some, but not all, holographic techniques; we discuss wavelength selection in light of this distinction. For holograms that do not allow for local control of color, such as display holography, the color contributions depend on the surface reflectances in the scene; the monochromatic sources point sample these reflectances. From this sampling, we show that the problem of wavelength selection is equivalent to that of finding efficient approximations to the tristimulus integrals. We conclude that three sources are often insufficient for accurate color reproduction, and we suggest wavelengths for holography with three, four, or more wavelengths. For holograms that do allow for local color control, the color science involved is similar to that of raster displays. Therefore, only three primaries are necessary. However, we describe situations where only two primaries are sufficient. This conclusion follows from the dichromatic theory of color reflection, which postulates that often the reflection of light from a surface contains only two color components.

In this paper we will describe techniques for increasing considerably the diffraction efficiencies of silver halide recordings and also techniques for achieving pseudo and true color recordings. The techniques were developed with mass replication in mind and a design for a second generation `Holocopier' will be discussed.

Holograms may be superimposed in a holographic medium by a number of techniques such as angular, phase-encoded, and wavelength multiplexing. For typical architectures, crosstalk increases as the bandwidth of stored data increases. The number of superimposed holograms in an ideal medium is limited by its length L, the wavelength of light (lambda) , and index of refraction n, such that for crosstalk-limited storage we can superimpose up to 2nL/(lambda) holograms of high bandwidth. In practice, however, the properties of real materials depart from the ideal through index inhomogeneities and scattering centers, dispersion in the material response as a function of grating spatial frequency, and dispersion as a function of the wavevector and polarization of both incident and scattered light. We discuss the impact of these properties on holographic data storage and describe material, device, and system strategies designed to minimize these effects.

Reality of holographic image can be effectively improved by multicolor reconstruction. This fact is applicable to real-time 3D display by computer generated hologram (CGH). However, generating CGH for multicolor imaging in real-time is quite difficult because a CGH contains huge amount of information and it is multiplexed by the number of primary colors for multicolor imaging. Moreover, an optical system for multicolor reconstruction tends to be rather complicated. This paper presents a new method to reconstruct 3D multicolor images from CGH. In this method, three sub-holograms reconstructing primary color images are sampled respectively to reduce the amount of computation and realize the simple optical system. Fringe patterns are displayed on only one spatial light modulator and color crosstalk images are eliminated with color filtering system to ensure that each sub-hologram is illuminated only with the light of the appropriate color. As the experimental results, multicolor images from CGH using this method and the improvement of calculation time to generated multicolor images are shown.

Dichromated gelatin has been established as the most frequently used recording material for the obtention of holographic optical elements and new applications are being found for photopolymers in previously unexplored areas such as holographic interconnects. However, photographic emulsion from the beginning has been and continues to be the most used holographic recording material. This is due to the relatively high sensitivity and ease of processing of this material, improved processing chemistries, commercial films, and the repeatability of the results. In this paper we will analyze different sources of noise in photographic emulsions such as intermodulation noise, noise gratings and non-linear noise, and the influence of the photochemical process on the previously noise sources cited. Bleached emulsions by rehalogenating and solvent process will be considered and silver halide sensitized gelatin will be present as a solution in transmission holograms. At the same time, new developers and new noise models will be presented under the supposition that non-linear response of the recording material is due to the photochemical process.

A durable and practical architectural installation of an image hologram that can be used to modify the direction of light from a natural or incandescent source. Working from a silver halide master prepared by the author, transfers were made by The Polaroid Corporation to their photopolymer recording material. The H2 was then applied to tempered glass using an index matching material. The glass panels are typical of those used in aluminum mullioned entries in contemporary building. The reference and read out angles of the hologram were arranged in such a way as to advantageously modify the output of the metal halide light sources used to illuminate the space. Solar tracking specular metal strips maintain reference angle during daylight at a constant input. The holograms appear as thin strips of transparent material applied to glass until the visual field is entered, then a bright and wide field image is viewed. The hologram serves to redirect approximately forty percent of the light falling on its surface deeper into the building.

Certain mechanical structures create colors when they are illuminated by light. This is achieved whenever a wide illuminating spectrum is filtered through some physical processes such as diffusion, scattering, or interference. Periodicity in the structures generally leads to iridescence as in the case of opals and holograms; conversely, interferential construction can generate broad band spectra such as the ones displayed at the reconstruction stage of some Lippmann color photographs. The characteristics of the materials and processes used to make such pictures are enhanced through an analysis of their microstructure. Energy spectra generated by interference in resonant structures and in Lippmann photographs relate closely to the volume distribution of the scatterers they are made of.

In this paper we present a new simple and efficient technique based on Fourier transform to generate holograms by computer. This technique does not take into account the classical techniques of phase codification. Referring to the holographic principle (off-axe holograms of Leigh & Upatniek) studied first by Burch or Huang & Prasada, a reference source has been included in the global calculation. In the second part of this paper, the production of the holograms using a commercial photographic film and a laser printer is described and experimental results are presented.

This paper introduces a variety of new techniques for holographic displays, offering an active time element for viewer dynamics. In interactive systems, viewers trigger dramatic changes in holographic images. Light and projection events alter the holograms in response to viewers' movements. Reconstruction light angle changes, digital video and computer-generated animation all play roles in these systems. LCD video projection onto holograms also led to a study of holographic screens suitable for color-coding depth into screens.

It is well known that a coherently illuminated conventional lens-based optical system can be used to display either the spatial frequency spectrum or the image of an object which are located in different planes. But, to get both of them in a single plane is difficult. We have suggested a simple method of achieving this. Two holographic optical elements (lens) of two different focal lengths are multiplexed on the same hologram, one focal length being double of the other. The multiplexed holographic lens is utilized to display the image and the spectrum of an object in a single plane in two spatially separated positions. Preliminary experimental results are presented.

In this paper we discuss a number of issues which affect the performance tolerances of substrate mode holograms (SMHs) used for optical interconnect systems. We examine the effects of emulsion uniformity, thickness variation, and index variation on the ability to accurately determine the diffraction angle within the substrate. The experimental results for the environment stability of SMHs are presented. The effects of emulsion thickness change and cross-coupling on the diffraction efficiency of a 1 X 2 multiplexed SMH are also described.

A fuzzy control model in image formation qualities of holograms manufactured in dichromated gelatin; Agfa 8E75 and other holographic recording material are described. A new model based on the fuzzy set theory is presented to control spectral shifting from the frequency of construction laser beam to the frequency of request. We are concerned with new simplified procedures inserted in ordinary hologram manufacturing process. From the modulation mechanism in these holograms we seize the intrinsic qualities and our model of fuzzy set analysis show to produce good general agreement with the experimentally measured image formation qualities.

Magneto-optic data storage is an emerging read/write storage technology with many potential applications in consumer computer systems. One of the limitations to this development is the cost of the read/write head. This device must provide high optical power during the write phase, and sense a small change in the polarization of the beam reflected from an MO disk during the read operation. Typically the head consists of many individual optical components which must be aligned and accurately assembled, and contributes significantly to system cost. Two important elements in the head are a leaky beamsplitter and a polarization beamsplitter. In this presentation we discuss the design parameters and performance characteristics for these beamsplitters formed in dichromated gelatin. Experimental grating performance is also given.

Usefulness of the Plate Optics with grooved base plates in constructing hologram recording equipments was reported in the previous paper. This paper reports an improved type of Plate Optics called Mole type Plate Optics, and proposes a simple computer-aided design for constructing optical systems on the Mole type Plate Optics.

A practical head mounted display (HMD) has to be light enough and bright enough to wear and view without undue strain on the users head or eyes. A 10 pound CRT based helmet is not always out of the question but binocular or stereo HMDs using LCDs rather than CRTs need only weigh in at around one pound complete with electronics and are far more comfortable to wear. The space bandwidth product or pixel count of LCDs is now approaching that of CRT type displays but LCDs could use a big boost in brightness, especially for see thru designs. The see thru or head up style has many user advantages and this paper addresses ways to more efficiently transmit photons from the source to the eye in one such design. All of the components that are used to improve performance may be made holographically or in an alternate fashion. The most practical method of construction is probably a toss up for some components.

Holographic Interferometry has been successfully employed to characterize and test the behavior of diverse types of structures under stress. Such applications of holographic technique have proven to be among the most effective methods of modal and dynamic analysis available. The technology is non-destructive, real-time, and definitive in allowing the identification of vibrational modes, displacements, and motion geometry. Structures can be analyzed with very low amplitude excitation and the resultant data can be used to adjust the accuracy of mathematically derived structural models. Holographic methods have offered a powerful tool to aid in the primary engineering and development of complex circuit board assemblies which are used in highly mobile platforms. Avionic, undersea, and even automotive systems involve applications where the environment presents large vibrations and stresses which can affect operation and structural stability. These are ideal requisites for analysis using advanced time-average holographic methods in the initial engineering of such advanced systems.

We report on the application of holographic measuring techniques to various inverse scattering and tomographic imaging applications. The common feature in these applications is that the total transmitted field, when an object is illuminated by coherent radiation, is composed of the coherent sum of the incident wave and the scattered wave, forming in essence a Gabor hologram of the scattered wave and preserving its phase and amplitude. The object can then be reconstructed from the complex scattered field if the phase and amplitude information are extracted from the hologram. We discuss several methods for image reconstruction from the measured holograms. One such method is direct backpropagation, which is useful in multiview tomographic imaging of 3D objects, such as in optical diffraction tomography. Other methods discussed involve the use of iterative and non-iterative algorithms to retrieve phase information from the hologram(s) and other a priori information. These methods are also applicable to twin-image elimination in Gabor holography and to wavefront sensing. We present computer simulation and experimental results of using holograms in tomographic imaging and inverse scattering using several of these methods.

Laser holographic interferometry has been developed to provide a direct optical transonic flow diagnostic tool. It is often convenient, due to the needs of passage instrumentation and blade fixtures, to restrict optical access to one side of the test facility. To overcome this limitation a reflective holographic system has been devised which uses one of the internal tunnel walls as a mirror surface. However, due to the movement of the facility, spurious rigid body vibration information is added to the transonic flow data. A numerical method has been developed by Warwick University and demonstrated on the Laval nozzle flow facility at EPFL which uses a digital fast Fourier transform algorithm to remove the superimposed background information. A further method known as phase unwrapping is used to extract quantitative numerical data from the interferometrically formed images automatically. A complication to the experiment was created by the non-linear deflection of glass window between the two holographic exposures. The deflection was determined experimentally to be of a parabolic nature and has been successfully removed. This was achieved by post processing the unwrapped fringe data.

The use of a low power He-Ne laser (5 mW) and a nonlinear photorefractive crystal is presented in this paper for achieving real time edge enhancement. A Barium titanate crystal is used in the degenerate of four wave mixing mode for obtaining optical phase conjugation.

We propose and demonstrate a novel method to improve the addressing accuracy of the holographic associative memory. The experimental results are given.

High precision measurement and mensuration of holographic images requires accurate replay in the real-image mode of reconstruction to produce an image which preserves all the characteristics of the original scene. When hologrammetry is applied to the inspection of underwater structures and components, the hologram is now recorded of subjects located in water and replayed in the laboratory in air. The refractive index mismatch between recording and replay spaces introduces optical aberrations into the reconstructed image which can seriously impair image fidelity. We have employed both ray tracing and third-order aberration theory to evaluate the extent of the aberrations and to assess methods of aberration correction. A unique solution relies on the change of wavelength of light as it passes through water and allows a deliberate mismatch of recording and replay reference beams to compensate for the refractive index mismatch. We present simple analytic expressions for the aberrations encountered, and show that a substantial improvement in image fidelity can be obtained by employing refractive index compensation. Finally, we review the practical implementation of the technique and outline the conditions which must be satisfied before the residual aberrations can be reduced to tolerable levels.

Using holographic grating as multiple beam generator the new applications of holographic grating in focal length, curvature radius of spherical mirror, astigmatism, distortion, curvature radius of convergent wavefront measurements are reported, some experiments and analyses of related problems are presented in this paper. It is shown that many parameters can be measured accurately using holographic gratings. Holographic grating (HG) is a sinusoidal grating and has many advantages, e.g., compact, lightweight, easily making, low cost, free ruling error and ghosts etc., it is generally used as a dispersion element in monochrometer and beam splitter in interferometry or diffraction interferometer. In this paper, the new applications of HG in optical test are described and some experiment results are reported.

Because of their high impact and sharpness, we believe that holograms make better teaching tools than conventional images, and one day will be common in medical texts and journals. To be maximally effective, often there must be labels or arrows within the images. Ideally these should be applied when the master is made, but they can be affixed to the image plane copy at a later date. Because of the constraints of the holographic medium, lacking a pulsed laser, one is limited to making images of rigid objects such as bones and anatomical models, though the technique of plastination makes tissue specimens solid enough to make acceptable images with continuous beam lasers. 1 . Putting the label in the master Using continuous beam lasers, the labels must be rigidly affixed to the platform holding the specimen. If the object is inflexible—such as a bone— the label or arrow can be glued directly to it. Reusable adhesives (such as FUN TAK) work reasonably well , though permanent glues are better. If the specimen is plastinated tissue—which is somewhat elastic—the label must be affixed to the base which is fastened to the table. 2. Adding a marker to an image plane copy. If one already has a hologram and wishes to put a label on it, press-on letters and arrows can be applied and burnished to the glass plate. The characters should be affixed to the front or non-emulsion side before the back side is painted black. Once it is painted it is virtually impossible to see where in the image one is putting the letters.

The frequency response curve--laser holographic method which studies the tonal quality of violin's and musical instruments. The method is based on macro measure of frequency response curve and full used sensitivity of laser holograph on weak vibration. We have analyzed violins of different tonal quality and have summarized fine violin's holographic mode. A new measuring method on tonal quality of musical instruments is being developed. We take the microscopic holograms of a violin when it is being vibrated (time--average method), and also with the frequency response curve, to analyze and measure a violin's vibration, to calculate the amplitude of the top and back plate of a violin, to find out the plate of a violin's plate where is should be repaired and micro quantity (micrometer), to change the interval of a violin's box (top and back plate) to improve the violin's tonal quality, to explore the quantitative rules of a whole violin's fine quality.

We present the results of numerical calculations, the experimental data of studying the fluctuation spectra of speckle-field intensity at longitudinal vibration of diffuse objects. A method has been developed for determining the diffuser vibration amplitude by measuring the amplitude ratios of the first two harmonics of the spectrum.

A key element of the optical image processing system is an image memory to temporarily store a huge amount of information between processing. Attempts have been made to use a silver halide photographic plate, a non-linear photorefractive crystal, a liquid crystal display and other elements as the image memory. However, none of these elements has proved satisfactory with respect to the following criteria: write and erase by an electrical method, signal-to-noise ratio of stored images, size of memory area and optical resolution. A thermoplastic photographic plate (TPP), in view ofits advantages oflarge memory capacity and ability to write and erase electrically, has been used for real time holography. However, the TPP is subject to the drawback of a high signal-to-noise ratio and has not been suitable for the image memory of the optical image processing. Recently, the authors conceived three methods to eliminate the drawback, and applied the TPP to holographic defect detection in periodic patterns. The TPP was used as the image memory and defect images were separated by spatial filtering and holographic optical image processing. Our results showed that 0.09 pm defects can be detected with signal-to-noise ratio 3.

A method is presented for rapid processing of high volumes of reflection holograms recorded in rolls of DuPont OmniDex^TM photopolymer films. This process includes high-volume continuous holographic replication, color tuning lamination and scroll over heating. Performance data for commercial OmniDex films processed with this method is presented. Performance and yield data from trial production runs demonstrate process capacity of at least 2500 square feet per day.

A holographic image dot-matrix printing system is described. The initial image to be printed is first loaded into the computer memory by any of the existing methods (scanner, CCD camera, etc.) or synthesised by the computer. This image can then be edited or corrected both in colours and structure with specially designed software. The resulting hard copy (holographic image) is printed as on the conventional matrix printing device. The only difference is that instead of pins the "writing lightpen" is used to record (print) the dots on the light sensitive material. Each dot of the complete image is modulated by a periodic structure (holographic grating). An advantage of the following system is because the nickel shim can be directly removed from the surface relief generated on a high resolution silver halide material.