Integral imaging systems are imaging devices that provide 3D images of 3D objects. When integral imaging systems work in their standard configuration the provided reconstructed images are pseudoscopic; that is, are reversed in depth. In this paper we present a technique for formation of real, undistorted, orthoscopic integral images by direct pickup. The technique is based on a global mapping of pixels of an elemental-images set. Simulated imaging experiments are presented.

A LC panel is layered on the LCD panel with the same pixel structure by matching each pixel to display stereoscopic images. The images for the LCD and LC panels are prepared by taking square root of sum of squared intensities and intensity ratio, respectively, of corresponding pixels from the stereoscopic image pair. The layered LCD panel enables to display each view image of the stereoscopic image pair with the full resolution of the panel and stereoscopic images with high quality.

We address the optical system for three-dimensional (3D) sensing, visualization and recognition of biological microorganisms. A digital holographic microscopy records Fresnel digital hologram of the biological microorganism. 3D image of the biological microorganism is computationally reconstructed by inverse Fresnel transformation of the digital hologram. For 3D recognition, two methods are presented. One is 3D morphology-based recognition and the other is based on statistical estimation and inference algorithms.

Integral imaging (II) is a promising technique for sensing and visualizing of three dimensional (3D) images because it produces autostereoscopic images without special illumination requirements. As with any 3D imaging, in order to produce high quality 3D images, it is required to capture, record, transmit, process and display an enormous amount of optical data. Therefore, a central challenge that rises is to store and transmit efficiently the huge amount of information. This can be done by applying appropriate data compression techniques that remove efficiently the inherent redundancy within the captured data. In this work we survey previously developed II compression methods and, compare their performance. We present a new technique to cope with a common problem with some of the II compression methods, namely the choice of the compression depth to be applied in the various dimensions representing an II.

We present an algorithm for stereoscopic conversion of two-dimensional movie encoded in MPEG-2. The stereoscopic algorithm consists of segmentation process and depth determination process. In the segmentation process, we segment the image based on the dc information and the motion vector information encoded by MPEG-2. After the segmentation, depth of each segment is determined by examining the motion vector and the overlapped region of the segment.

Integral imaging (integral photography) is one of the promising three-dimensional display techniques, which is composed of pick up and display steps in general. In pick up step, a two-dimensional image array, elemental images that have three-dimensional information of the object, is obtained. In display step, the elemental images are displayed and integrated through a lens array for observer to see 3D image. Thus making elemental images in the pick up step is an important process since the 3D information of the objects is included in the elemental images through this step. In this paper, we examine the problem of synthesizing elemental images of virtual views from an elemental image using the line of sight (LOS) algorithm. LOS can handle any number of input images while simultaneously using the information from all of them, and can be applied in integral imaging to generate elemental images. However, very few images are usually enough to provide reasonable synthesis quality. The explanation of the proposed algorithm is provided and the results on real images are presented also.

In this paper, we present a system to reconstruct a free view of a partially occluded object by using computational integral imaging. The system is analyzed to sense information of off-center views from a elemental images set. To obtain unobstructed images with high resolution, low focus error, and large depth of focus, synthetic aperture integral imaging utilizing a digital camera has been adopted. Two novel algorithms are proposed: 1) an algorithm for reconstructing volumetric perspective images and 2) an algorithm for scaling reconstruction images at arbitrary distances.

Computation of the coherent point-spread function (PSF) involves evaluation of the diffraction integral, which is an integration of a highly oscillating function. This oscillation becomes severe as the value of defocus increases and thus makes PSF computation a costly task. We present a novel algorithm for computing the PSF, which works efficiently for any arbitrarily large value of defocus. It is theoretically proved that the complexity of our new algorithm does not depend on the value of defocus. We also develop an implementation scheme for the new algorithm. Using this implementation we experimentally demonstrate the low complexity of our method. We quantify the rapid convergence and numerical stability of this method over all ranges of defocus. Finally, we compare the computational cost of this method, in terms of time and memory, with other numerical methods such as direct numerical integration and the Fast Fourier Transform.

A novel method for multiplier modulo using optical signal processing is presented. Multiplier modulo is an important process in a factorization algorithm. In the method, modulo operations are executed by phase modulation. We construct a prototype system of the presented method. The constructed system consists of a Michelson interferometer with a photo detector array. In the system, mirrors are put on both object and reference arms. A mirror in the object arm is slightly tilted and the angle depends on parameters for target multiplier modulo. An obtained interference fringe has information about desired results for modulo operations. The most feature of the presented system is that it achieves massive data processing for mulitiplier modulo in parallel with only simple implementation. We show experimental results to verify usefulness of the presented method. Moreover, we study on expansion to implement factorization.

We consider physical principles of realizing the Bragg regime of one-, two-, and three-phonon scattering of light in optically anisotropic crystals under specially elaborated conditions. The exact and closed analytical models for describing these regimes are developed. The performed analysis reveals an opportunity of realizing 100% efficiency of light scattering in these regimes, and computer simulations illustrate the obtained results. Possible applications lie in the fields of creating large aperture spatial modulators of light. In connection with this, the problems of optimizing the bandwidths and resolution of such modulators are studied.

Numerous phase-shifting interferometry digital hologram compression techniques have been proposed and investigated in the literature. We review some of the most important of them and compare their performance under the same conditions. Comparison is performed based on reconstruction quality. As holograms contain three dimensional information we investigate the compression effects on different distance reconstructions and reconstructions corresponding to different viewing angles. In this way we evaluate the compression performance of the methods not only on a single reconstruction, as it was done so far, but for aspects of the whole range of the holographic three dimensional information. We use holograms of multiple object scenes or objects with sufficient details on different depths so that both parallax and depth effects can be demonstrated.

Digital Holography is the technique of numerically reconstructing a three-dimensional (3D) image containing both amplitude and phase information from a two dimensional (2D) interference pattern recorded by the CCD. In this paper, we study the effects of varying the coherence length by using light from two types of source's (1) coherent laser light and (2) spatially filtered incoherent light from a Light Emitting Diode (LED). We present results using both calibrated test objects and biological samples with view to developing a 3D object recognition and classification system.

In this work we present the experimental synthesis of fully complex fields employing computer generated holograms, implemented with an amplitude liquid-crystal spatial light modulator (SLM). The hologram transmittance is obtained by adding an appropriate bias function to the real cosine computer hologram of the encoded signal. The effect of finite pixel size in the SLM is compensated by digital pre-filtering of the encoded complex signal. For the purpose of this work, we consider an appropriated bias function for a modulator in which the amplitude transmittance is coupled with a linear phase modulator. This type of coupled phase appears in a commercial Twisted Nematic Liquid Crystal Display (TNLCD), configured to provide amplitude modulation, with only two polarizers as external components. We employ a commercial TNLCD to generate experimentally Laguerre-Gauss beams and non-diffracting Bessel beams of several orders.

In this work we present a single exposure method for recording multiple holograms in reflection holography. In this novel method, the input pattern is a segmented image composed of alternating slices of several original images and modulated by a lenticular lens array sheet. A set of object beams can be produced simultaneously, which are angularly separated on the recording plane and overlap one reference beam at the same time. Therefore, only one exposure is needed for holographic recording multiple holograms. Experimental results show that a lenticular lens array sheet placed as a modulator in the path of the object beam provides a simple yet effective ingredient of creating multiple images for single-exposure holography. The proposed method is especially useful for one-step write/read multiple holograms and for stereoscopic display applications.

We recently proposed a novel 3D microscopy technique called stimulated parametric emission (SPE) microscopy. Stimulated parametric emission microscopy shares the four-wave-mixing properties with CARS (coherent anti-stokes Raman scattering) microscopy. The SPE microscope maps the distributions of the third-order nonlinear susceptibility, or information about the nonlinear refractive index and two-photon absorption coefficient of a certain electronic-excitation level of materials such as unstained living cells. Wide-band or equivalently ultra-short pulses from a mode-locked Ti:sapphire laser and an optical parametric oscillator were used for the pump and dump pulses with different central optical frequencies (ω₁ and ω₂) for the SPE process. The pulses are then focused into the sample and the third frequency (ω₃ = 2ω₂-ω₁) component is generated in the sample due to the nonlinear optical susceptibility. This signal pulse having the third frequency and the reference pulse generated by using a standard material are superposed on an array sensor. If we introduce a proper time delay into the signal and reference pulses, the mixing process produces a fringed pattern on the array sensor. Simple calculation enables us to obtain the stronger signal levels of the third-order nonlinear susceptibility that are separated into the real and imaginary parts. Spatial distributions of the complex susceptibility at the several bands can in principle be obtained. We will show the feasibility of this method and a 3D image of the complex susceptibility of a living cell.

This paper introduces an optical solution to (bounded-length input instances of) an NP-complete problem called the traveling salesman problem using a pure optical system. The solution is based on the multiplication of a binary-matrix, representing all feasible routes, by a weight-vector, representing the weights of the problem. The multiplication of the binary-matrix by the weight-vector can be implemented by any optical vector-matrix multiplier. In this paper, we show that this multiplication can be obtained by an optical correlator. In order to synthesize the binary-matrix, a unique iterative algorithm is presented. This algorithm synthesizes an N-node binary-matrix using rather small number of vector duplications from the (N-1)-node binary-matrix. We also show that the algorithm itself can be implemented optically and thus we ensure the entire optical solution to the problem. Simulation and experimental results prove the validity of the optical method.

This paper summarizes the results of experiments in developing a method for extracting 3D information from a scene by means of a polarimetric passive imaging sensor. This sensor provides full Stokes vector at each sensor pixel location, from which, degree and angle of linear polarization are computed. Angle of linear polarization provides the azimuth angle of the surface normal vector. The depression angle of this surface normal vector is obtained in terms of the emitting object's index of refraction, from the solution of an equation derived from Fresnel equations, snell's law, and percent of linear polarization. Results of the application of this approach on simulated infrared polarimetric data are provided.

The one-shot phase-shifting digital holography using phase difference of orthogonal polarizations is proposed. Using a CCD camera with pixelated polarizers, three images for phase analysis can be obtained simultaneously. The proposed method can be applied to a moving object, because a complex field of the wavefront of a 3D object can be obtained in a single exposure.

In this paper we concern ourselves with the subject of superresolution in Digital Holography (DH), i.e. increasing the resolution of DH system beyond its limit. The limiting factor regarding resolution in a DH system is the pixel size, which is equal to the smallest resolvable unit. By careful superposition of different digital holograms captured of the same 3-D object, we attempt to increase the resolution of the reconstructed image and equivalently to increase the range of angles of reconstruction. This is accomplished by rotating the input object wavefield either by rotation of the object (it is 2-D) or by rotation of a mirror that is placed between the object and the CCD. Rotating the input wavefield shifts the wavefield in the hologram plane in space and spatial frequency. Therefore, those parts of the hologram field that contained energy at too great an angle for recording and were therefore arranged to be adjacent to and not on the CCD will be shifted in space onto the CCD face and will also be shifted to a recordable angle. We outline a sub-pixel correlation technique to stitch the consecutive holograms together in both the space and spatial frequency domains. Multiple captures enable us to record a DH of large resolution and angle of reconstruction. Storage and reconstruction of the stitched hologram is also discussed and experimental results are given. The method may be applied with any existing form of DH. We use the Wigner Distribution Function to qualify and quantify the method.

We present a new method for numerically reconstructing digital holograms on tilted planes. The method is based on the angular spectrum of plane waves. Fast Fourier transform algorithm is used twice and coordinate rotation in the Fourier domain enables to reconstruct the object field on the tilted planes. Correction of the anamorphism resulting from the coordinate transformation is performed by suitable interpolation of the spectral data. Experimental results are presented to demonstrate the method for a single-axis rotation. The algorithm is especially useful for tomographic image reconstruction.

We investigate the principles of digital holography based on the Wigner distribution function (WDF). We apply the WDF to the analysis of generic optical setups which are used to record and reconstruct image Fresnel holograms. We use the graphical representation of the Wigner chart to derive various important properties, including the required space-bandwidth product of the digital hologram, CCD sampling and numerical reconstruction and the optimum required object size to optimize the system efficiency. This allows us to offer a simple comparison of the various recording schemes. The analysis also allows us to graphically compare the numerical reconstruction methods and the restrictions it may impose on the CCD parameters. We show how this insightful analysis leads us to a new method of digital holography which we call 'dual-shift' DH.

In this paper, we analysis the effect of partial occlusions in scenes captured using digital holography. We reconstruct the scene from different perspectives. These reconstructions are then combined, allowing one to overcome foreground occlusions that are obscuring one's view of the scene. The analysis in this paper is carried out with the aid of the Wigner distribution function, allowing us to visualize the energy of the object wavefield and the occluding object wavefield in phase space. We show that by iteratively selecting different views, the original scene can be reconstructed e±ciently. This technique would be useful in situations where transmission of the whole digital hologram, or exhaustive reconstruction of every perspective, was not feasible. We provide results using optically captured digital holograms of real-world objects, and simulated occlusions.

We propose a novel multifactor encryption-authentication technique that reinforces optical security by allowing the simultaneous AND-verification of more than one primary image. We describe a method to obtain four-factor authentication. The authenticators are: two different primary images containing signatures or biometric information and two different white random sequences that act as key codes. So far, optical security techniques deal with a single primary image (an object, a signature, or a biometric signal), not combined primary images. Our method involves double random-phase encoding, fully phase-based encryption and a combined nonlinear JTC and a classical 4f-correlator for simultaneous recognition and authentication of multiple images. There is no a priori constraint about the type of primary images to encode. Two reference images, double-phase encoded and encrypted in an ID tag (or card) are compared with the actual input images obtained in situ from the person whose authentication is wanted. The two key phase codes are known by the authentication processor. The complex-amplitude encoded image of the ID tag has a dim appearance that does not reveal the content of any primary reference image nor the key codes. The encoded image function fullfils the general requirements of invisible content, extreme difficulty in counterfeiting and real-time automatic verification. The possibility of introducing nonlinearities in the Fourier plane of the optical processor will be exploited to improve the system performance. This optical technique is attractive for high-security purposes that require multifactor reliable authentication.

An optical identification system based a three-dimensional (3D) phase object is presented. The identification is implemented by the correlation between a speckle pattern of the 3D phase object and stored speckle patterns. To achieve a high level of recognition, we use two speckle patterns of the 3D object obtained by illuminating two wavelengths. Experimental and numerical results are presented to show the effectiveness of the proposed system.

We consider a Double Random Phase Encoding (DRPE) Encryption/Decryption system in which the image encryption/decryption process is performed numerically. In this paper we present a key-space analysis of the (DRPE) algorithm which is used to encrypt two dimensional (2-D) images. We map the assiocated error for every phase-key in the key-space of a particular system to get a visual representation of the spread of phase-keys for the system and so assess its security from a key-space perspective.

In this work we propose different types of combination of several diffractive lenses written onto a single programmable liquid crystal display (LCD) in order to increase the depth of focus (DOF) of the imaging system. Each lens is designed in such a way that lenses with consecutive focal lengths provide amplitude distributions along the axis that overlap. The lenses are spatially multiplexed onto the LCD following different schemes: by sectors, by rings and randomly. We compare experimentally the Point Spread Function (PSF) in transversal planes along the optical axis with a single lens and with the designed multiplexed lenses. The intensity profiles are also compared. The random multiplexing is the combination technique that brings the best results in terms of DOF.

In this article we study the use of the cubic-phase pupil function for extension of the depth of field of task-based imaging systems. In task-based design problems the resolution of interest varies as a function of the object distance due to change in magnification. This introduces a new challenge in the design process. We discuss how the optimal design criterion of task-based imaging systems is fundamentally different from that of visual imaging systems and formulate the optimization problem. We discuss how the use of the cubic-phase pupil function changes the spectral signal-to-noise-ratio (SNR) and modulation transfer function (MTF) in the range of the depth of field in order to fulfill our design requirements. We introduce an approximation to the problem of maximizing SNR and show that it is amenable to analytic treatment. We derive an explicit expression for the optimized cubic-phase pupil function parameters for a general problem of this class, thus establishing an upper bound for the extension of the depth of field using cubic-phase Wavefront Coding.

The hardware implementation of a high throughput Max Log Map Serial Concatenated Convolutional Code (SCCC) turbo decoder for an optical channel employing 64 Pulse Position Modulation (PPM) is described. The Max Log MAP turbo decoder is in contrast to a corresponding optimal log MAP turbo decoder. The Max log MAP decoder is the preferred turbo decoder for applications requiring high throughput. The performance of both the max log MAP decoder and log MAP decoder are compared to the theoretical performance values. Tradeoffs used in the implementation of the high throughput Max Log Map 64 PPM decoder are discussed.

Projecting high peak power laser pulses to a specific location in space and time can significantly improve laser weapons, secure optical communications, and remote spectroscopy. Current laser systems send a pulsed beam from laser to target causing collateral damage to objects in the path for a laser weapon system, opportunities for compromising security in communications, and averaging of measurements along the path for spectroscopy. We analyze and simulate a system that beamforms M mode-locked lasers, each having N modes, to achieve a peak power at a target in space and time that is NM times greater than that for M non-mode-locked non-beamformed lasers. In low atmospheric turbulence, a peak power of 10kW can be projected to a point in space and time by a 10 × 10 array of 2W laser diodes, each having 50 modes. Effects of atmospheric turbulence are discussed and were investigated in our previous papers.

We show that long depth of focus can be achieved with a pixelated lens (PL) encoded onto a reconfigurable spatial light modulator (SLM). Our PL has a phase distribution similar to that of a conventional axilens. Additionally, our resulting reconfigurable PL is employed in a novel shape recovering system. A feature of this system is that no moving parts or motors are required to scan a three-dimensional object. Numerical simulations and experimental results are shown.

Hyperspectral sensors can facilitate automatic pattern recognition in cluttered imagery since man made objects often differ considerably from the natural background in absorbing and reflecting the radiation at various wavelengths i.e., the identification of the objects is based on spectral signature of the objects in the scene. In this paper, a unified approach for pattern recognition with known object signature is formulated by generating Gaussian mixture model to effectively utilize the underlying statistics of the data cube. To estimate the model parameters, enhanced version of the stochastic expectation maximization (SEM) algorithm is employed, which is also used successfully for image classification by reducing the unwanted information in the data cube. In the proposed scheme, at first we used the modified SEM to identify the different classes in the scene including the desired object class. Then, the Mahalanobis distance between the desired object signature and distributions of the mixture model is employed to detect the object class. Finally, the maximum a posteriori (MAP) probability for each pixel is estimated and Bayesian decision law is applied in order to isolate object pixels. The proposed algorithm has been tested using real life hyperspectral imagery and the results show that the algorithm shows robust performance in noisy environment.

In hyperspectral imaging applications, the background generally exhibits a clearly non-Gaussian impulsive behavior, where valuable information stays in the tail. In this paper, we proposed a new technique where the background is modeled using stable distributions for robust detection of outliers. The outliers of the distribution can be considered as potential anomalies or regions of interest (ROI). To further decrease the false alarm rate, it may be necessary to compare the ROI with the given reference using a simple method. In this paper, we applied one dimensional fringe-adjusted joint transform correlation technique, which can detect both single and multiple objects in constant time while accommodating the in-plane and out-of-plane distortions. Simulation results using real life hyperspectral image data are presented to verify the effectiveness of the proposed technique.

Hyperspectral sensor imagery (HSI) is a relatively new area of research, however, it is extensively being used in geology, agriculture, defense, intelligence and law enforcement applications. Much of the current research focuses on the object detection with low false alarm rate. Over the past several years, many object detection algorithms have been developed which include linear detector, quadratic detector, adaptive matched filter etc. In those methods the available data cube was directly used to determine the background mean and the covariance matrix, assuming that the number of object pixels is low compared to that of the data pixels. In this paper, we have used the orthogonal subspace projection (OSP) technique to find the background matrix from the given image data. Our algorithm consists of three parts. In the first part, we have calculated the background matrix using the OSP technique. In the second part, we have determined the maximum likelihood estimates of the parameters. Finally, we have considered the likelihood ratio, commonly known as the Neyman Pearson quadratic detector, to recognize the objects. The proposed technique has been investigated via computer simulation where excellent performance has been observed.

This paper proposes an algorithm for detecting object of interest in hyperspectral imagery using the principal component analysis (PCA) as preprocessing and spectral angle mapping. PCA has found many applications in multivariate statistics which is very useful method to extract features from higher dimensional dataset. Spectral angle mapper is a widely used method for similarity measurement of spectral signatures. The developed algorithm includes two main processing steps: preprocessing of hyperspectral dataset and detection of object of interest. To improve the detection rate, the preprocessing step is implemented which processes hyperspectral data with a median filter (MF). Then, principal component transform is applied to the output of the MF filter which completes the preprocessing step. Spectral angle mapping is then applied to the output of preprocessing step to detect object with the signature of interest. We have tested the developed detection algorithm with two different hyperspectral datasets. The simulation results indicate that the proposed algorithm efficiently detects object of interest in all datasets.

Conventional 3D movie systems with the special glasses such as polarized glasses provide us touchable spatial images. However, these 3D imaging systems require the observer to wear the glasses. Our research group would like to realize the glasses-less 3D imaging system to construct an interactive spatial imaging environment. The authors have researched the 3D displays and applications. We have ever proposed 3D displays using the slit as a parallax barrier, the lenticular screen and the holographic optical elements(HOEs) for displaying active image^1,2,3. We developed a prototype field-lens 3D display with a tracking system. This system consists of the user's position detection system and the spatial imaging system. In this paper, we describe the method of 3D measuring using a single camera for tracking users' positions and a 3D display system using a field-lens which can display full screen high resolution views. This 3D display can solve the traditional defect that the horizontal resolution of each image is divided in half.

We developed a prototype tabletop holographic display system. This system consists of the object recognition system and the spatial imaging system. In this paper, we describe the recognition system using an RFID tag and the 3D display system using a holographic technology. A 3D display system is useful technology for virtual reality, mixed reality and augmented reality. We have researched spatial imaging and interaction system. We have ever proposed 3D displays using the slit as a parallax barrier, the lenticular screen and the holographic optical elements(HOEs) for displaying active image^1,2,3. The purpose of this paper is to propose the interactive system using these 3D imaging technologies. In this paper, the authors describe the interactive tabletop 3D display system. The observer can view virtual images when the user puts the special object on the display table. The key technologies of this system are the object recognition system and the spatial imaging display.

An adaptive phase-input joint transform correlator for real-time pattern recognition is presented. A reference image for the correlator is generated with a new iterative algorithm based on synthetic discriminant functions. The obtained reference image contains the information needed to discriminate reliably a target against known false objects and a cluttered background. Calibration look-up tables of all used opto-electronic elements are included in the design of the adaptive phase-input joint transform correlator. The resulting joint input image for the correlator is a real-valued bipolar image, which cannot be directly displayed with a conventional amplitudeonly spatial light modulator. Commonly two optical correlations and post-processing are used. We utilize a phase-only spatial light modulator in the input plane. A new phase-only joint input image is obtained by a monotonic mapping the intensity to phase information. The phase-only image is easily introduced into an optical setup. In this case we need just one correlation and no post-processing. Experimental results are provided and compared with those obtained with computer simulations.

Optical security systems have attracted much research interest recently for information security and fraud deterrent applications. A number of encryption techniques have been proposed in the literature, which includes double random-phase encryption, polarization encoding, encryption and verification using a multiplexed minimum average correlation energy phase-encrypted filter. Most of these reports employ a pseudo-random code for each information to be encrypted, where it requires individual storage capacity or transmission channel for further processing of each information. The objective of this paper is to develop an optical encryption system employing quadrature multiplexing to enhance the storage/transmission capacity of the system. Two information signals are encrypted using the same code but employing two orthogonal functions and then they are multiplexed together in the same domain. As the orthogonal functions have zero cross-correlation between them, so the encrypted information are expected to be unaffected by each other. Each encryption and multiplexing process can accommodate two information signals for a single code and a single storage cell or transmission channel. The same process can be performed in multiple steps to increase the multiplexing capability of the system. For decryption purpose, the composite encoded signal is correlated using the appropriate code and the appropriate function. The proposed technique has been found to work excellent in computer simulation with binary as well as gray level images. It has also been verified that the encrypted images remain secure, because no unwanted reproduction is possible without having the appropriate code and function.

Spatial light modulators (SLMs) are key components of collinear holographic storage. Collinear holography utilizes coaxially aligned information and reference beams which are displayed simultaneously by a same SLM for writing process, and also employs reference beam for retrieving process. We developed magneto-optic spatial light modulators (MOSLMs) which have high-speed switching and applied them to transmission-type collinear holography. In this study, we investigate performance of collinear holography with magneto-optic spatial light modulator. The Bit error rate was 8.9×10^-3 for single hologram. To examine the performance of shift-multiplexing, reconstructed image was disappeared after 3 μm shift. MOSLMs is suitable for collinear holography in terms of transfer rate especially.

This paper represents fabrication and properties of an improved current-driven 128 by 128 magneto-optic spatial light modulator (MOSLM) consists of arrayed pixels patterned with 14 micrometers square of 16 micrometers pitch. It could be driven successively only drivelines without a bias field by external coil to saturate magnetization. The magnetic pixels were embedded into the nonmagnetic substrate both to avoid magnetic switching error and to make the pixels array surface smooth. The switching field of arrayed pixels was reduced to 145Oe by annealing them to decrease the growth induced magnetic anisotropy. This value was about half of the conventional 128 by 128 MOSLMs. Moreover, copper straight drivelines were used for decreasing electric power consumption and applying a homogeneous magnetic field to the pixel. This drivelines structure enabled to switch the individual pixels reversibly keeping a single domain state, therefore, the successive driving of writing and erasing various checker patterns could be possible without bias field by external coil. The electric power consumption was decreased about 70 %. The switching speed of one pixel was 25 nanoseconds. It is more than a thousand times faster than other types of SLM, for example, 10 to 30 milliseconds for liquid crystal (LC) type, and 10-20 microseconds for micro electro mechanical systems (MEMS) type.

Accurate registration of image pairs is critical to a number of image processing tasks, including image splicing, change detection, image co-addition, and super-resolution processing. We have applied digital Fourier plane correlation and optical joint-transform correlation to image registration. We demonstrated RMS registration accuracy of 0.09 pixels for a digital system and 0.1 pixels for an optical system. The experimental system uses an electrically addressed spatial light modulator (SLM) at the input plane of a joint transform correlator and an optically addressed SLM at the Fourier plane. We operate our optical system in burst mode at the rate of 50 correlations per second. The paper describes digital and experimental implementations of the image registration system. We discuss preprocessing algorithms used to prepare inputs for correlation, post-processing algorithms to interpolate the output, and the effect of these processing variations on system performance.

Every invention and discovery has its own roots. This article will describe my personal experiences and encountered with Emmett Leith; as an inventor and his technological break through for the discovery of Laser-Holography. The legacy of his discovery, outgrowth from, and development, will also be shown. A tribute to Yuri Denisyuk, who has just passed away, is also included.

The development of the wave nature of light, over the last 430 years, resulted in the off-axis or Leith hologram. Earlier contributions were expressions for the resolution of microscopes and telescopes and the first color photographs. X-ray diffraction by crystals and recorded photographically (actually "holograms" recorded without a reference beam) eventually produced images of atoms in crystals. D. Gabor was the first to add an in line reference beam to a diffraction pattern by passing a coherent beam through a tenuous scene. Interference between the light scattered by the scene and the unperturbed beam was recorded (as in crystallography by a photographic plate, the hologram). The message was reconstructed when the plate was re illuminated with colored light. It is believed that the off axis reference beam was discovered during the classified development of side looking radars. The invention of the visible helium neon laser clarified the importance of the off axis hologram which produces 3D imagery with continuous parallax (miracle #1) of the recorded scene. It was found that the off axis hologram reconstructed the amplitude and phase of the original wavefront, making possible interferometric comparisons (miracle #2). Reconstruction of the conjugate wavefront was achieved by reversing the direction of the reconstructing beam (miracle #3). Phase conjugated holograms makes possible 3D microscopes and can be used to correct different optical systems. In hind sight, it could be said that the off axis or Leith hologram was too obvious, as are all other great discoveries.

With their introduction of diffused illumination Leith and Upatnieks introduced one the most essential inventions in holography and in modern optical engineering in general. They observed for the first time the enormous capability of utilizing the phase of a light field in a random-like manner for manipulating its characteristics when propagating in space. The use of phase freedom beyond lens-like manipulations in optical engineering was born. We like to place their invention into a broader context and discuss its enormous impact on most actual developments in optical engineering.

A digital holographic metrology technique is described for measuring the three-dimensional shape of manufactured parts. The technique uses optical fibers to set up a near equal path interferometer, steps through multiple frequencies with a tunable laser, steps through multiple phases using a fiber based phase shifter, uses an off-axis parabolic mirror to collimate the light, and generates a digital hologram that leads to surface flatness measurements accuracies better than 1 micron over large surfaces. An example result for an automobile engine part is given using a Coherix Inc., Shapix^TM 2000 instrument.

Holographic optical elements are a critically enabling component of modern spectroscopy and spectral imaging systems. While the most common holographic elements are essentially those discovered in 1962 by Leith and Upatnieks, several decades passed prior to the effective integration of holography and sensing. Over 5 decades Emmett Leith was a prime mover in both the birth and the maturation of computational holographic sensors. Recent demonstrations of the unique utility of holographic filtering suggest that continued improvements in materials and recording processes for Leith's original concept will yield tremendous results. This paper describes the multiple order coded aperture (MOCA) spectrometer as an example of the potential for advanced holography in computational sensors.

We describe novel methods for waveform synthesis and detection relying on longitudinal spectral decomposition of subpicosecond optical pulses. Optical processing is performed in both all-fiber and mixed fiber/free-space systems. Demonstrated applications include ultrafast optical waveform synthesis, microwave spectrum analysis, and high-speed electrical arbitrary waveform generation. The techniques have the potential for time bandwidth products ≥10⁴ due to exclusive reliance on time-domain processing. We introduce the principles of operation and subsequently support these with results from our experimental systems. Both theory and experiments suggest third order dispersion as the principle limitation to large time-bandwidth products. Chirped fiber Bragg gratings offer a route to increasing the number of resolvable spots for use in high speed signal processing applications.

The theoretical and numerical difficulties encountered in the analysis of volume holographic information storage and beam shaping are mitigated here by a mathematical procedure to expand the reconstructed wave into a superposition of simple Gaussian beams. The theoretical result is used here to explore some characteristics of bit-oriented holographic storage in volume holograms and the possibility of using volume holograms for beam shaping. Simulation results demonstrate the power of the method, show good correspondence with earlier experimental studies, and provide clues for further developments.

In line Frauhofer holography with collimated recording and spherical reconstruction beams can eliminate the primary spherical aberration. The off-axis primary aberrations with this mode are described. Rayleigh's quarter wavelength rule is then used to set the aberration limited size resolution. General solutions are obtained and the particular example of Ruby recording and HeNe reconstruction lasers is described. The problem was suggested to the author by E. N. Leith during an earlier SPIE conference presentation.

Holographic spectroscopy has been a subject of continuing interest for several decades. Recently, the use of optical filters to allow fast discrimination and segmentation of images has been shown to be very powerful. Conventional filters are restricted to being nonnegative, but that restriction does not apply to holographic filters. So more useful filters can be designed and used holographically to produce a pixel-by-pixel spectral image analyzer.

We describe a holographic technique capable of sampling dynamic events at 150 femtosecond time resolution. We apply the technique to the study of the nonlinear propagation of high energy pulses through gas and condensed media. The holograms are recorded as a digitized image from a CCD camera and reconstructed numerically to retrieve the refractive index change during the nonlinear optical process. We show dramatic differences in the pulse propagation characteristics depending on the strength of the nonlinear coefficient of the material and it's time response. Both positive and negative index changes have been measured in different media. The holographic technique allows us to distinguish the very fast positive index changes that are generally attributable to the Kerr nonlinearity from the negative index changes that result from free electrons generated by multiphoton ionization.

We have developed model that describe transformation of time modulated optical signals by the double optical and electrical interferometer: beam coupling and holographic current in the semiconductor crystals. We consider non-local response, when dominant mechanism of the space charge formation is diffusion or drift in a high external electric field. Both phase and amplitude modulation is considered (linear ramp phase modulation, sinusoidal modulation, step-like modulation). For the sinusoidal amplitude modulation slow-down of optical signal is described. Experimental results on CdTe crystal with IR CW laser (P=100mW, wavelength 1064 nm) are in agreement with theoretical predictions. Effective group velocity was slow-downed to 555 cm/s for the modulated signal with period of 8ms.