Volume-scanning three-dimensional display that uses an inclined image plane

A novel three-dimensional display based on a volume-scanning method that uses an inclined light-source array and a mirror scanner is proposed. With this technique it is possible to display three-dimensional images that satisfy all factors for human stereoscopic vision. Three-dimensional images of 8 x 8 x 8 pixels, 40 mm x 40 mm x 40 mm in size, with a frame rate of 12.7 Hz were obtained as real images through an experimental system that uses a galvanometer mirror and a LED array.     

Principles of a three-dimensional recording model for short wavelength magnetic recording

Principles are provided for a method of evaluating the magnetization of a magnetic recording tape element running in front of a recording gap. The distributions of switching fields P(Hc) and magnetization axes P(θ, φ) used in the calculations are derived from simple experimental results. The output level is calculated by means of the reciprocity principle. The first application of the method concerns certain phenomenological aspects of magnetic recording. As a practical example, a qualitative explanation of the output level curve versus the recording current for short wavelength signals is given; the advantage of microgaps for recording are demonstrated and finally, the circular Bitter patterns discovered by S. Iwasaki are shown to be predicted by the model. This study is a first step toward a more general solution including the demagnetizing field.     

Real-time pickup method for a three-dimensional image based on integral photography

We studied integral photography (IP), which creates three-dimensional autostereoscopic images. In particular we studied the possibility of a new method that uses a television camera to shoot directly numerous real images produced by a lens array. Unlike the conventional IP method in which the film is placed immediately behind a lens array, this method employs a television camera, which enables us to shoot moving pictures. Of a number of factors affecting the process of image pickup, we examined some optical factors and compared them with those obtained by the conventional IP method. The results show that with this new direct pickup method that uses a television camera, we can obtain an IP image like those obtained by using the conventional IP method. Further, we conducted an experiment with an high-definition TV camera, confirming the production of an autostereoscopic image by using a display device that combines a liquid-crystal panel and pinholes.     

Preparation of plastic spherical microlenses by use of a fluoropolymer stencil and oil-bath heating

A new method for fabricating plastic spherical microlenses was developed, which allowed self-alignment of lenses and self-organized formation of a spherical shape. First a low-surface-energy fluoropolymer thin film was deposited and patterned as a stencil. Then photosensitive phenol resin was patterned on it as the lens material. Finally the resin was annealed in an oil bath to form a sphere. The molten phenol resin spontaneously formed a sphere and positioned itself in the center of the fluoropolymer ring pattern as a result of the difference of surface free energy and the equivalently zero-gravity condition in the oil bath. When a light-emitting-diode printer head was loaded with spherical microlenses, its optical output increased by 1 order of magnitude.     

Digital three-dimensional image correlation by use of computer-reconstructed integral imaging

We use integral images of a three-dimensional (3D) scene to estimate the longitudinal depth of multiple objects present in the scene. With this information, we digitally reconstruct the objects in three dimensions and compute 3D correlations of input objects. We investigate the use of nonlinear techniques for 3D correlations. We present experimental results for 3D reconstruction and correlation of 3D objects. We demonstrate that it is possible to perform 3D segmentation of 3D objects in a scene. We finally present experiments to demonstrate that the 3D correlation is more discriminant than the two-dimensional correlation.     

A combined surface integral and finite element solution for a three-dimensional contact problem

A method is described to determine contact stresses and deformation using a combination of the finite element method and a surface integral form of the Bousinesq solution. Numerical examples of contacting hypoid gears are presented.     

Wide-viewing-angle integral three-dimensional imaging system by curving a screen and a lens array

A wide-viewing-angle integral three-dimensional imaging system made by curving a screen and a lens array is described. A flexible screen and a curved lens array are incorporated into an integral imaging system in place of a conventional flat display panel and a flat lens array. One can effectively eliminate flipped images by adopting barriers. As a result, the implemented system permits the limitation of viewing angle to be overcome and the viewing angle to be expanded remarkably. Using the proposed method, we were able to achieve a viewing angle of 33 degrees (one side) for real integral imaging and 40 degrees (one side) for virtual integral imaging, which is four times wider than that of the currently used conventional techniques. The principle of the implemented system is explained, and some experimental results are presented.     

Photonic content-addressable memory system that uses a parallel-readout optical disk

We describe a high-performance associative-memory system that can be implemented by means of an optical disk modified for parallel readout and a custom-designed silicon integrated circuit with parallel optical input. The system can achieve associative recall on 128 × 128 bit images and also on variable-size subimages. The system's behavior and performance are evaluated on the basis of experimental results on a motionless-head parallel-readout optical-disk system, logic simulations of the very-large-scale integrated chip, and a software emulation of the overall system.     

Performance of a write-once multilayer optical disk that uses transparent recording material with an optical switching layer

A volumetric optical disk that has multiple transparent films with optical switching layers is used as a recording medium to increase the number of recording layers. In the disk the optical switching layer is adapted to reduce decay of laser energy and increase reading and recording sensitivity. Well-defined marks of approximately 100-nm depth can be placed precisely on the transparent films by a focused laser beam. Writing and reading of a four-layer recordable disk, fabricated by molding and spin bonding, have been demonstrated experimentally. The volumetric disk can achieve a high recording capacity with conventional optical pickups.     

Optical encryption system that uses phase conjugation in a photorefractive crystal

We implement an optical encryption system based on double-random phase encoding of the data at the input and the Fourier planes. In our method we decrypt the image by generating a conjugate of the encrypted image through phase conjugation in a photorefractive crystal. The use of phase conjugation results in near-diffraction-limited imaging. Also, the key that is used during encryption can also be used for decrypting the data, thereby alleviating the need for using a conjugate of the key. The effect of a finite space-bandwidth product of the random phase mask on the encryption system's performance is discussed. A theoretical analysis is given of the sensitivity of the system to misalignment errors of a Fourier plane random phase mask.     

Analysis of an optical depth converter used in a three-dimensional integral imaging system

An optical depth converter that uses a lens array pair is analyzed theoretically and experimentally. We present a theory of depth conversion and explain the effects of the system parameters in the optical depth converter by using wave-optical analysis. Ray-optical analysis is applied to the investigation of the tendencies of the system parameter effects. We also show that the optical depth converter can be used for the three-dimensional screen in projection-type integral imaging systems.     

Implementation of a high-speed face recognition system that uses an optical parallel correlator

We implement a fully automatic fast face recognition system by using a 1000 frame/s optical parallel correlator designed and assembled by us. The operational speed for the 1:N (i.e., matching one image against N, where N refers to the number of images in the database) identification experiment (4000 face images) amounts to less than 1.5 s, including the preprocessing and postprocessing times. The binary real-only matched filter is devised for the sake of face recognition, and the system is optimized by the false-rejection rate (FRR) and the false-acceptance rate (FAR), according to 300 samples selected by the biometrics guideline. From trial 1:N identification experiments with the optical parallel correlator, we acquired low error rates of 2.6% FRR and 1.3% FAR. Facial images of people wearing thin glasses or heavy makeup that rendered identification difficult were identified with this system.     

Estimation of surface pose with a physically-based ultrasonic image model

State-of-the-art approaches to shape analysis in medical images use a variety of sophisticated models for object shape. We have developed an image model that permits the application of these approaches to ultrasonic images, with detailed methods for representing rough surfaces. Our physically-based, probabilistic image model incorporates the combined effects of the system point-spread function (PSF), the tissue microstructure, and the gross tissue shape. At each image pixel, the amplitude mean and variance are computed directly from the model, characterizing the combined influence of shape, microstructure, and system PSF. Calculation of the SNR0 is used to further classify each pixel as Rayleigh- or non-Rayleigh-distributed. This characterization was used here to generate a data likelihood representing any set of images of a given surface by a probability density conditioned on the surface pose, or rotation and translation. The utility of this likelihood was demonstrated by applying maximum likelihood estimation to infer the pose of a cadaveric vertebra from simulated images of its surface. Successful results were achieved using derivative-based optimization algorithms for a data set of only three images. With a quasi-Newton BFGS algorithm, error in 15 of 20 trials was less than 0.4 degrees in rotation and 0.2 mm in translation. Estimation was inaccurate in only 1 of 20 trials. These results illustrate the potential of a physically-based image model in a rigorous approach to image analysis and also serve as an example of quantitative assessment of the model via performance in a specific application.     

Considering asymmetrical manufacturing cost information in a two-echelon system that uses price-only contracts

Consider a basic “price-only” supply chain interaction in which the “players” are a manufacturer and a retailer. The manufacturer sets the wholesale price ($w/unit) of a product she supplies to a retailer, who in turn sets the retail price ($p/unit) at which he sells to the consumers. The product's demand curve is a function of p. The players select to play one of several non-cooperative games such as the manufacturer-Stackelberg game. How should the players set their prices w and p? Most existing studies assume information symmetry i.e., the cost and market parameters are known equally and perfectly to both players. In reality, the retailer's knowledge of the manufacturing cost c is often controlled by the manufacturer. This paper considers explicitly the asymmetry of knowledge in c. This approach reveals interesting and surprising deviations from earlier symmetrical-c-knowledge results. Moreover, the approach also ameliorates some of the internal inconsistencies within the symmetric-information framework. We also show how the effect of knowledge asymmetry varies with the shape of the demand curve and with the degree of relative dominance between the players. We find that under a linear demand curve a manufacturer should overstate c, which is an intuitively expected result. However, under an iso-elastic demand curve she benefits herself and the entire system by understating c, which is counter-intuitive. Also, under asymmetric c-knowledge, the simultaneous decision (or “vertical Nash”) game becomes non-viable under a linear demand curve, but the game becomes quite viable and desirable under an iso-elastic demand curve.     

Albumen as a relief recording media for spatial distributions of infrared radiation. Fabrication of interference gratings and microlenses

It is shown that a relief is generated when spatial distributions of infrared light (lambda = 10.6 microm) are recorded on albumen films. The relief can be applied to the fabrication of microelements, such as diffraction gratings and microlenses. Examples are shown.     

Study of a spherical head model. Analytical and numerical solutions in fluid–structure interaction approach

This paper deals with the analytical and the numerical computation of elastoacoustic vibration modes. We determine in the present study the eigenfrequencies and the modal shapes of the system of brain, cerebro-spinal fluid (CSF) and skull. Two models are presented in this work: an elastic-acoustic model assuming a rigid skull and an elastic-acoustic-elastic model assuming a deformable skull. The analytical results are compared with the numerical solution obtained using the software Comsol Multiphysics. It is shown that eigenfrequencies and more significantly the modal shapes are strongly influenced by the interaction between solid phases (brain and skull) and the cerebro-spinal fluid. Finally the influence of the CSF compressibility and thickness on the natural frequencies was investigated.     

Enhanced three-dimensional integral imaging system by use of double display devices

We propose an enhanced three-dimensional (3D) integral imaging system using multiple display devices. Experimental results with double devices prove the improvement in the image depth for a given image quality. We present experiments on an enhanced 3D integral imaging system using double display devices, in which two 3D subimages that cover different depth ranges are separately generated in each device, and then they are combined with a beam splitter to reconstruct the whole 3D image with an enhanced depth of view. In a similar manner, the double-device system can also be used to obtain a wider viewing angle by combining two images with different viewing angle ranges. We discuss the possibility of 3D integral imaging systems using multiple display devices as extensions of the system with double display devices.     

Improvement of the generalization capability for a pattern-recognition neural network that uses a Gaussian-synapse neuron model

A method for improving the generalization capability for optical pattern recognition by use of a Gaussian-synapse neuron model is discussed. By the dispersive effect of the Gaussian function the input images are blurred and then fed into a multilayer neural network for learning and recognition. The effectiveness of this method is demonstrated in two-dimensional shift- and scale-invariant optical pattern recognition.     

Optimization of a three-dimensional digital image correlation system for deformation measurements in extreme environments

An optimized 3D digital image correlation (3D-DIC) system using active optical imaging is developed for accurate shape and 3D deformation measurements in nonlaboratory conditions or extreme high-temperature environments. In contrast to a conventional 3D-DIC system using white or natural light illumination, the proposed active imaging 3D-DIC system is based on a combination of monochromatic lighting and bandpass filter imaging. Because the bandpass filter attached before the imaging lenses allows only the actively illuminated monochromatic light to pass through and blocks all light outside of its bandpass range, the active imaging 3D-DIC system is therefore insensitive to serious variations in ambient light in nonlaboratory environments and to the thermal radiation of hot objects in extreme high-temperature environments. Two challenging experiments that cannot be performed by a conventional 3D-DIC system were carried out to verify the robustness and accuracy of the developed active imaging 3D-DIC system. Because a much wider application range can be achieved with relatively simple and easy-to-implement improvements, the proposed active imaging 3D-DIC system is highly recommended for practical use instead of the conventional 3D-DIC system.