The technique of color photography with black-and-white film is presented. It is basically a physical method for color photography, and so has the advantages of no color fading and environmental pollution problems. The prototype instruments for the color encoding and color decoding are also introduced.
Conjugate image plane correlator with holographic disk memory is proposed. Optical correlation between the conjugate images reconstructed from holographic disk and input image on liquid-crystal television are executed under the rotation of disk. It was found that nevertheless of Fourier hologram recording with pseudorandom diffuser it is possible to take out the diffuser from original hologram recording scheme and get correlation signals between input and reconstructed conjugate images at output plane of two lens imaging system under image reconstruction process. The generation of conjugate replicas with high contrast causes an exact matching with input image which results in high recognition performance for autocorrelation signals. The real-time character recognition by optical parallel high- speed processing for 2D images with position normalization are demonstrated.
A set of new algorithms for image connection is presented in this paper. Firstly in order to improve the quality of medical ultrasonic image, we adopt the adaptive weighted median filter to suppress the speckle noise and employ the adaptive histogram equalization to enhance the details. Secondly the image connection based on the image matching technique is performed. Thirdly to get a seamless and smoothed connected image we employ interpolating and smoothing operation. At the last part of the paper, we give the experiment results and conclusions.
A nonlinear joint transform correlation (NLJTC) used for moving object tracking was proposed in this paper. In the proposed NLJTC, a high contrast liquid crystal light valve was used to implement real-time joint power spectrum nonlinear processing. Moving object tracking principle is described. Experimental results were given and analyzed.
Adaptive nonlinear optical correlators and joint transform correlators with a nonlinearity in the correlator's Fourier plane are investigated with the purpose of optimization (in terms of the correlators' discrimination capability in target location in cluttered background) of nonlinearities' parameters and of judgment of the discrimination capability's sensitivity to such design factors as limitation of the nonlinearity's dynamic range and resolution power.
Optical distortion can be corrected by a digital circuit in the process that the images are grabbed or displayed. The correcting process is in fact the transformation from the distorted image plane to the distortionless image plane. A standard calibrating sample plate is used to get the transformation function. To meet the requirement of real time operating, transformation function is presented as a table form. Therefore the correction is just a course of table-lookuping. The digital circuit has been designed to realize the correction process. And the software is working with the hardware to get the transformation table. Some experiment data are proposed in the paper to show the results of the calibration and analyze the correcting errors.
A optical system to get the wavelet transform coefficient which needed in encoding system is discussed in our paper. A reference beam was used in our system to get the positive or negative information of the signal. An reconstruction based on the signal proved the feasibility and reliability of our system. Some problems are discussed in the end of this paper.
The effect of the quality of printing paper, which is a main factor of the reproduction of picture and character, on the reproduction quality of picture and character by the optical information theory is studied. The optical transfer function that is applied to evaluate the imaging character of printing paper is obtained.
This paper presents a method based on the image matching to extend the measuring range of AFM. By this way, we can extend the measuring range of AFM without changing the hardware structure of AFM system. It is proved that this method is powerful to resist the noise and the images can be matched precisely and quickly. In principle, the measuring range of AFM can be extended unlimitedly.
In this paper, a four-channel holographic associative memory system with electrical data bank was presented, whose basic processing unit was a photorefractive-based correlator. Furthermore, a diode-pumped solid-state laser was introduced into the system, which exhibited a lot the potentiality of a compact associative memory with multi-channel synchronizing processing architecture.
This paper presents a new system of echocardiographic visual processing and quantitative analysis, which can be used in computer aided diagnosis. Detection of the left ventricular boundaries in cardiac images is essential for the quantitative analysis. Our new approach incorporates a priori knowledge of heart geometry (a set of constraints), its brightness distribution, and Sobel operator detection in polar coordinate into the boundaries detection algorithm. Then we employ the outline chain-code tracking technique for echocardiogram computation and quantitative analysis. The procedure is demonstrated by using echocardiograms of the human heart.
In this paper, we first introduce the definition of quantum information optics and expound the essential distinction between quantum and classical information optics. Secondly, the five great subjects on the research of quantum information optics are summarized. Finally, the recent experimental progress on the preparation (or generation) of quantum states (or quantum information) in some semiconductor devices and materials are introduced and reviewed in detail.
We report a new experimental result to generate open-loop correlation nonclassical state of the light by means of the technique of quantum information copy in a series-coupled LEDs system at room temperature. Quantum fluctuation of the intensity difference between open-loop twin beam of the light has been squeezed below the standard quantum limit of the light by 9.5 dB (88.8%) at the frequency of 2 MHz, the corresponding squeezed bandwidth is broader than 1 - 50 MHz.
Optimal incoherent filters are proposed for distortion- invariant and noise-tolerance correlation. The optical transfer function (OTF) of the correlator is specified as a realizable phase-only term which is modified by a passband function. The phase-only term is optimized by the simulated annealing for producing a sharp and distortion-invariant correlation peak, and the passband function is selected by a direct iterative search algorithm to achieve the noise- tolerant image recognition. The designed OTF is generated by dual-filter synthesis. The correlation output is obtained from the subtraction between the correlation of two realizable filters with the input image. Optical experiments and computer simulations show that the proposed correlator can yield a sharp correlation peak with excellent distortion robustness and noise tolerance.
A new method to produced self-similar pattern is described in this paper. The method that applies a series of primary pictures makes Fourier transformation and convolution operation. If all pictures are characterized by similar Fourier spectrums, which have different scales, the fractal images can be obtained in the output plane. Experiments show the regular multifractality can be generated by optical instruments completely with this method.
This paper describes the application of parallel processing technique in optical pattern recognition. We present a multiplexing parallel processing system. A plane optical lenslet array is used to produce multiple paralled beam, which read out multiimage of object from LCLV. The parallel iterative algorithm is adopted to design the bank of eigenfunction filters. Multiplexing correlation results are processed and determined synthetically. At last the recognition results are provided.
A real-time hybrid joint transform correlator (JTC) with parallel processing architecture that use two liquid crystal light valves spatial light modulators, two VP32 image boards and two optical wavefront-division multiplexers as the key parts was presented. Using this hybrid JTC< real-time high- efficiency joint transform correlation, high-speed joint transform correlation and four-channel joint transform correlation were realized. The hybrid JTC system has also been used in the domain of morphological complex-valued kernel scale-space image processing. In this paper, the principles of the above experiments are described, experimental results are also given and analyzed.
One of the methods of boundary expansion of holographic interferometry measurements consists of IR-lasers using as radiation sources. At the present time a photothermoplastic materials can be considered as one of the reverse materials registrating IR radiation. The area of their spectral sensitivity lies in the ranges of 400 - 1150 nm. A certain method of recording has been developed for the purpose of expansion of the range wave lengths registered on thermoplastic carriers.
Analytical solutions for the equations that describe the steady-state photorefractive two-wave mixing with rapidly phase-modulated beams are presented. The results show that the volume index of refraction grating automatically aligns so that it coherently couples the signal and local oscillator fields just like a fixed beamsplitter in a conventional homodyne receiver structure.
The implementation strategy of optical wavelet transform for texture information processing is discussed in this paper. An opto-electronic hybrid system is constructed for texture segmentation, which is based on the multi-channel filtering framework in the early stages of human visual theory. First, a traditional optical system with a Damman grating as the beam splitter and a bank of Gabor wavelets as the channel filters is set up for feature extraction, and several clustering algorithms are then used for feature integration. Furthermore, a novel binary optical element with the functions of splitting, filtering and imaging is designed and fabricated to simplify the traditional system. The experimental results and the primary applications are also provided.
Handling of optical information has become increasingly digital in nature and digital concept and techniques play an ever more dominant role. The representation of the data to be handled is of concern in the system design. Such systems consist of several units classified by their function: encoding, transmission, processing, storage, and decoding of information. Coding schemes have been introduced and developed to accommodate transducer problems between distribution of energy and material properties.Electronic devices and systems have had a significant impact on the treatment of 2- and 3-D information and have to be adapted and developed accordingly. Gradually, sophisticated computational abilities have been added together with ideas to convert 1-D modulated signals into 2-D ones. The gained additional degrees of freedom can be used to optimize the process and sampling and quantization requires refined software to filly utilize existing hardware. The flexibility to include processing of the information locally and/or globally has opened new extensions of and possibilities in, the field of synthetic counterparts of established physical methods and techniques. The spectrum of digital optical coding techniques range from sequential, pixelwise to iterative methods. Major classes of algorithms will be illustrated. Competing specific requirements, needs and tolerances will influence the choice of a suitable algorithm.
Keywords: digital holography, cmputer-generated holograms, diffractive elements, hologram design
Recently there has been a great deal of interest in the optical implementation of wavelet transforms for image processing. In this paper, we discuss applications of the wavelet transform to image analysis, rotation and scale invariance, and pattern recognition in the presence of background noise. We describe a method for scale and rotation invariant pattern recognition based on wavelet features of an image. Finally, we give an example of using discrete wavelet filters to extract information from an image.
Presented is the analyses of influence of Hadamard coding system on imaging error in laser coding Synthetic Aperture Radar. The result shows that using Hadamard coding can increase the amplitude of echo signal and reduce noise. Coding and sampling circuit possess good linearly respond property.
A diffractive optical element (DOE) offering a uniform illumination for ICF is designed by geometrical transformation combined with Yang-Gu algorithm. By properly choosing the quantization opportunity, the DOE with 16 phase-levels generating uniform focal spots with rms < 4% and (tau) > 90% is obtained. The quality degradation of the focus caused by the noise of input beam is analyzed. Computer simulations show that the element has enough ability of anti-noise.
In this paper we show the relationship among the Lagrange invariant, the interference invariant and the space bandwidth product, they are important in geometrical optics, physical optics and information optics. And we give a method of calculating the space bandwidth product of optical system.
A new image nonlinear segmentation method which is based on feedforward multilayer neural network (MLN) is presented in this paper. The example of using proposed MLN technique for cross overlapped chromosome image segmentation is given. In contrast to gray-level threshold technique, the MLN method is based on spatial coordination classification. From the experiments it can be concluded that the MLN in particular shows promise of being a useful method for image nonlinear segmentation.
Despite of its slow learning time, back-propagation (BP) is one of the most widely used neural network training algorithms. In this paper, a nonlinear stretch method is presented that modifies the nonlinear activation function of BP algorithm to speed up the convergence. A invariant target recognition system based on BP neural network using this method and moment invariants is studied. Simulative recognitions on aircrafts and vehicles show that the speed of convergence is increased effectively.
We employ the genetic algorithm to design a binary optical element system which transforms the Gaussian beam into the uniform circular ring beam. The transformation system is composed of two binary optical elements with 8 phase levels which are placed coaxially. The numerical results indicate that the transformed wavefront has a near-desired waveform and high energy transformed efficiency (tau) equals 87.3%. The genetic algorithm is better that the other usually used algorithms such as input-output iterative algorithm and stationary phase algorithm. The comparison with the three algorithms are shown in this paper, too.
Binary interferograms can encode in a simple, reliable fashion, 1D phase variations. Here, we describe a simple technique for encoding as binary interferograms. Dammann array illumination, and Lohmann array illuminators.
In this paper, a new type optical splitters is described. The splitter, a varied phase structure grating which is made with binary optical technique, can continuously adjust splitting ratio of two light beams. The relation between splitters structure and two split beams energy is given by vibration curve method, experimental results are presented and discussed too.
This paper will review the requirements and status of the component and material technologies required to bring holographic storage successfully to the marketplace. Emphasis will be placed on satisfying the demanding system requirements, such as bit error rate and design margins, for an integrated, fully functional storage device.
Recent work on dynamic fiber holographic processes is discussed. Fabrication of single-crystal fibers using a laser-heated pedestal growth system is given. Angular and wavelength selectives are calculated which show that wavelength-multiplexed reflection fiber hologram offers higher and uniform selectivity. Channel cross-talk is also evaluated; we show that the cross-talk noise can be subsided by using narrower spectral light source. Applications of the fiber hologram to fiber-sensing and also to tunable filters are provided.
A new suggestion that there is a phase jump of (pi) in the boundary wave is put forward in this paper. This suggestion may be a supplement of Huygens-Fresnel principle. Based on this new suggestion, a series of new beam was invented, both outside and inside laser cavity. Especially, a new CO2 laser with equivalent beam quality factor M2e < 1 is achieved. It can be considered as the result of some controllable nonlinear self-focusing, and the physical background of deformed quantum mechanics.
Utilizing ultrashort laser pulses, the temporal and spatial resolution approach the same order of magnitude. In that case the limited speed of light sometimes causes large measuring errors if correction methods are not introduced. Therefore, we want to revive the Minkowski diagram, which was invented in 1908 to visualize relativistic relations between time and space. We show how this diagram in a modified form can be used to derive both the static holodiagram, used for conventional holography, including ultra-high-speed recordings of wavefronts, and a dynamic holodiagram used for studying the apparent distortions of objects recorded at relativistic speeds. The holodiagram explains the apparent distortions of wavefronts and objects both in the laboratory and in outer space.
Under certain well-defined circumstances, it is possible to record the yieldsx-t orbit or world line of a moving point source holographically. Computer holograms of world lines are also possible. Although aspects of this work were performed 30 years ago, this is the first systematic treatment of the subject.
A new physical model for volume hologram was proposed. Volume hologram was considered as a series coupled Fabry- Perot etalon. The multi beam interference makes band width of volume hologram to be very narrow. The positive feedback of Fabry-Perot provide high diffraction efficiency of volume hologram. Computer simulations based on the new model showed a good consistency with the coupled wave theory and previous experimental results.
The vertical angular selectivity of volume holographic gratings in photorefractive crystals is investigated both theoretically and experimentally. The vertical selective angle and the shape of the grating degeneracy lines are derived by using a simplified geometrical model relating the k-vector sphere to the reference point plane. The study shows that volume gratings have finite selectivity in vertical direction, so that grating degeneracy does not occur along vertical lines.
It is proved theoretically and experimentally in this paper that the diffraction efficiency and resolution of optical fiber image plane hologram can be enhanced by decreasing the single fiber core diameter of image-carrying optical fiber bundle and increasing the unit area fiber number.
To evaluate a hologram by measuring its optical density D, diffraction efficiency (tau) and signal-noise ratio SNR is a conventional method in holography. In this paper, a novel method is proposed for evaluation of a thin, phase holograms by testing phase modulation together with D, (tau) and SNR. Many properties of the thin, phase holograms are related to phase modulation, so that to control the value of phase modulation in making a thin, phase hologram is important. The value of the phase modulation of a hologram can be obtained by measuring the irradiance of its zero and first- order diffraction and calculating their ratio. This method will help holographers to obtain a perfect understanding of a thin, phase hologram and help them to choose the optimum parameters of exposure so as to obtain an expectation result. The theoretical analysis of this method are given and some applications are also introduced.
A systematic investigation is carried out on the optimization of diffraction efficiency (DE) of only methylene blue sensitized gelatin (MBG) holograms. The influence of the following factors on DE are studied: the concentration of methylene blue (Cm), the concentration of ammonium dichromate solution (Ca), swelling temperature (Ts), exposure (E) and the relative humidity of air (RH). This study shows that under the condition of Cm-0.009%; Ca- 5%; Ts within 35 - 45 degree(s)C; E-150 mJ/cm2; RH within 45 - 65%, an optimum DE of over 80%, even 90% can be achieved in MBG holograms. In our experiments we find that a moderate DE(35%) is obtained without dichromate solution in post- processing. In order to know the role which the condition of bathing the plate in a dichromate solution plays and the photo-chemical mechanism of forming the interference pattern in the films, the X-ray spectra are made, the Cr3+ ligands are not found; this means that the quantity of Cr3+ ligands is too small to measure, even if its is existing in the processed film. These results can not be interpreted with the normal photo-chemical mechanism of forming the holograms.
An experimental formula for slitless rainbow hologram diffraction efficiency will be obtained from speckle theory and multiple-exposure theory in this paper. The results obtained from this formula tally with a vast amount of experimental data. This paper will solve the problem that the diffraction efficiency of slitless rainbow hologram not be estimated in theory over a long time.
The effect of prehardening and processing procedure of dichromated gelatin (DCG) on the broadband characteristics of reflection holograms is researched in this paper. We present several parameters evaluating the performances of broadband reflection holograms, and establish a setup measuring diffraction efficiency of reflection holograms directly, and provides two methods for controlling DCG prehardening. The experiments are significant to the manufacture of reflection holograms in DCG.
In this paper a numerical simulation is used to calculate near-field intensity by `split light beam.' The calculation proves to be valid as we apply it to the plane wave. In the case of one dimension structure such as a compact disk sample, the near-field intensity profiles show a rather complicated structure. In many cases the near-field intensity does not represent the actual surface profile. The near-field intensity is strongly modulated by the surface structure. When the distance between the sample and the probe becomes larger, some subtle perturbation is added to the intensity profile, and a shift between the surface and the intensity profile became more clear. The shift may cause some problems when we use the optical probe as a multi- function probe to do some lithograph work or to position. In this paper, a comparison between the calculation and experiment results was made.
The number of display pixels required to present a holographic image can be reduced to a minimum determined by optical physics, but inevitably grows with the display size and angle of view The MIT holographic video system has recently been scaled up to provide images 85 mm high by 135 mm wide by ca. 200 mm deep, with an angle of view of 30=B0 and a vertical resolution of 144 lines. The minimum number ofpixels needed to support this display is 37.7 million (36 Mp), presented as 144 lines of 262 thousand (256 Kp). This large number of pixels presents considerable challenges for the interactive computation, communication and display of holographic video images. The presentation of such an image is made possible by optical parallelization of the display optics wherever possible. We use an 1 8-channel acousto-optical modulator, and a Fresnel-type moving mirror scanning system to overcome several practical limitations. The computation of such large holograms is speeded up by the elimination of as much information as possible from the hologram, notably its vertical parallax. Techniques of space discretization and table iookup reduce the computation time to a few seconds in most cases. Methods of "difftaction-specific' fringe computation and compression reduce the computation time even frirther. The use ofadaptive sub-sampling allows the lossless "compression" ofhologram data by a factor of two for speedy transmission and reconstruction at the display end of the channel. The general structure of the system includes an IBM Power Visualization System, which provides a 32-processor parallelized system for rapid compuation and compression of the holographic video pixels. A HiPPI link between the PVS and a specially-adapted digital image processing and frame store system (the Cheops system, designed for the Television of Tomorrow research program at MIT) allows transfer times of less than half a second. The output from eighteen synchronized 2-MB video memory circuits with arbitrarilylong line lengths are then converted to a 50-100 MHz signal suitable for the transducers for the acoustooptic modulators.
In this paper the demand for anti-counterfeiting holograms, the case examples of brand authentication, the current anti- counterfeiting techniques in China and the role of China Government in anti-piracy efforts are reported.
Compact reconstruction of hologram is an important technique to popularize the hologram widely. Edge illumination methods to realize this are reviewed and the features are discussed. The method to illuminate the hologram at large angle in air is also discussed and some experimental results are presented.
The yielding and displaying of the 3D images of object have been investigated for many years. The methods of designing non-spherical or complicated wavefront are important for fabrications of different optical elements with low aberrations, and also very useful for the synthesis of rainbow holograms of the 3D true-color objects. The display of 3D wavefront can be realized by several methods. In this paper the technique and system of holographic synthesis of computer designed-3D wavefront are described. The 2D amplitude distribution of light wavefront of object in the recording plane can be created by computer 3D image design and by sampling the wavefront in the angles. Then, these amplitude distributions after modified by computer are output into the holographic recording systems by means of high resolution liquid crystal display (LCD) plate to form the synthetic holographic master. The master is converted into image-plane rainbow hologram in the holographic systems. The advantages of the technique, compared with the CGH and conventional holographic method, are obvious. The LCD output is simple and fast. The wavefronts of true-color object can also be fabricated by this system. The different coding holographic gratings and elements, the true-color 3D rainbow holograms can be made successfully with the technique combined with spatial frequency-coding and color- controlling technology.
Very few possibilities are referred to give a solution to the problem of holographic television. We mean here holographic being any system capable of bringing images in continuous horizontal parallax. Occlusion is a necessary property for representing objects with realm, as opaque elements instead oftransparent ones. The only system we know that satisfies this requirements is being developed by Benton since 1989. It consists in processing the object information by Fourier transformation by very powerful parallel computing processing introducing this information in one crystal electrooptical modulator by means of acoustic waves while reading it by means of a laser. Color can be obtained by making a three-chromatic RGB system. The computer simulated images are, to our knowledge, well defmed in continuous horizontal parallax . It was recently reported 2 to have reached the size 8.5cm (V) x 13cm (H) x 20 cm3. We proposed a white light system capable of generating a vectorially addressed holo-like image This system was further developed recently to generate a sequence of TV planes where reach TV frame is seen oblique to a holographic screen, traversing it from its front to his back. A controlled mirror makes this plane to fill a volume by scanning along the screen, so that if we project a sequence of contour lines of an object it can be seen in continuous horizontal parallax, to a size of 1m3, up to now. First results using computer generated models will be described. The system has the possibility of occiussion by control of the spectral distribution when encoding each point, a development to reach in future work.
A new kind of method generating kinetic diffraction grating image is introduced in this paper. Its main property is that the technique of real time dividing light is used in the system. The work efficiency is raised much more than other method, and the angles between two thin beams for generating pixels are successive variable. The encoding principle of kinetic diffraction grating image is discussed. The concept of the grating spectral pallet is first proposed and the sampler of grating spectral pallet is given. The image can be generated to give satisfaction to custom with this grating spectral pallet. The image color can be in accord with the original image color, because there are as many grating spectral pallets as computer spectral pallets. The relation between the number of pallet and the angle of two thin beams is discussed. This kind of image is of high technology, short developing circle time and the properties of being kinetic and visible in 360 degree. It will be widely used in laser anti-counterfeiting, decorating and packing fields.
Recording of large-format color reflection holograms of the Denisyuk type has been performed in the new HOLOS' color holography facility in New Hampshire. Ultra-high resolution silver-halide emission of the Russian type is employed for the recording. With dichroic filter beam combination in the recording setup, simultaneous red-green-blue exposure is conducted. By this method, the RGB color balance ratio and overall exposure energy on the emulsion can be controlled independently. The facility is equipped with several high- power cw lasers (krypton-ion, argon-ion, and frequency- doubled Nd:YAG) to obtain three suitable laser wavelengths for color hologram production. A 30 foot long optical table enables HOLOS to generate color holograms up to 60 cm by 80 cm.
The one and two-step slitless methods are considering for rainbow hologram recording. The theory of the slitless rainbow holography and the Talbot effect in holography was developed on the basis of the Generalized Scheme for recording of rainbow holograms. The modulation theory and the Fourier analysis of optical signals was applicated by creation of this theory.
Techniques of making visible and concealed holographic secret codes based on optical moire phenomenon are described. Theoretical analysis, experimental results and the sample holograms with the secret codes are presented.
A novel method of two-step circular viewing rainbow holography is proposed and experimentally demonstrated. A large viewing angle circular viewing rainbow hologram recorded on a plane plate can be obtained by using holographic phase conjugation technique and aperture conjugation technique. Here, the strict conjugation reconstruction and aiming process to replace the image are not necessary. Also, there is no requirement of large aperture lens.
A circular-viewing color-coding rainbow holography with a group of circular coding slits is presented, in which the color coding holographic image can be observed around a 360 degree(s) viewing circle, and no particular optical elements should be used.
Master holograms with color coding are widely used in making true color embossed holograms, such as 2D holograms and stereograms. But the master hologram can not be used to record true color relief rainbow hologram of 3D object with single laser light. A new master hologram with both color and position coding for true color 3D embossed hologram is presented in this paper. The characteristics of the new master hologram are analyzed in detail.
In this paper, a novel color-encoder which has dual functions of a beamsplitter and a beamshaper is proposed. This encoder could acquire very good uniformity of light field with high diffractive efficiency. An algorithm which combining tracing algorithm, G-S algorithm and Y-G algorithm is used to design this encoder, the result by computer simulation calculation shows: the diffraction efficiency is up to 93.3%, non-uniformity is less than 0.01%. And a new approach to encode and make a phase element by using color- printer techniques is proposed in this paper as well.