This PDF file contains the front matter associated with SPIE Proceedings Volume 8855 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

Over the past decade, the field of medical image analysis research has undergone a rapid evolution. It was a collection of disconnected efforts that were burdened by mundane coding and file I/O tasks. It is now a collaborative community that has embraced open-source software as a shared foundation, reducing mundane coding and I/O burdens, promoting replicable research, and accelerating the pace of research and product development. This talk will review the history and current state of open-source software in medical image analysis research, will discuss the role of intellectual property in research, and will present emerging trends and technologies relevant to the growing importance of open-source software.

In this work we describe techniques for the generation of vortex beams, including vortex generating diffraction gratings and diffractive lenses, as well as some possible applications in optical image processing. We then analyze the description of radially polarized beams in terms of superposition of such vortex beams. We present some methods for the production of radially polarized light, that include patterned linear polarizers, specially designed liquid crystal devices and spatial light modulators (SLMs). We analyze the manipulation of this radial polarization by means of wave-plates, in order to obtain other non-standard spatially variant polarized light beams. Theoretical analysis are presented based on the Jones matrix theory, and experimental results are included for all cases.

We propose an asymmetric image encryption and decryption scheme based on phase-truncated Fourier transform and polarization encoding. An image bonded with a random phase mask is Fourier transformed and the obtained spectrum is amplitude- and phase-truncated. The phase-truncated value is encrypted using the polarized light in which two independent optical plane waves are used. The first plane wave illuminates the input image and is encoded into a given state of polarization. The second plane wave illuminates an intensity key image and is encoded into another state of polarization. Thus obtained two waves are mixed to obtain first level of encryption. The resultant is then passed through a linear polarizer (pixilated polarizer), to obtain the second level of encryption. For decryption, encrypted image is passed through the pixilated polarizer rotated at appropriate angles. Finally, decrypted image is obtained by computing inverse Fourier transform of retrieved phase-truncated value bonded with amplitude-truncated value. The proposed method offers flexibility in the encryption key design. We also checked immunity against special attack if polarization keys are unknown. Due to amplitude- and phase-truncation process the designed keys are asymmetric in nature. Results of numerical simulation are presented in support of the encryption scheme.

Among the existent technologies of spatial light modulator devices, parallel aligned liquid crystal on silicon displays (PA-LCoS) have found wide acceptance. They are especially interesting since they provide phase-only modulation with no coupling of amplitude modulation. Optimal use of these devices requires proper calibration of their modulation capabilities in order to minimize some degradation effects found in the literature, such as flicker or anamorphic and frequency dependent modulation. In this work we apply calibration techniques developed in our lab, basically the classical linear polarimeter adapted to be able to take into account the existence of flicker. This method enables to obtain both the average retardance and a good estimation of the magnitude of the phase fluctuation when flicker is present. Various addressing formats are discussed and variations in the magnitude of the applied voltages are considered in order to amplify the retardance dynamic range and to enhance linearity in the device. Finally, two electrical configurations intended for phase-only and amplitude-mostly modulation regimes, useful e.g. in diffractive optics, are given.

A new cardiac rate measurement method is proposed. Through the beam splitter prism, the common-path optical system of transmitting and receiving signals is achieved. By the focusing effect of the lens, the small amplitude motion artifact is inhibited and the signal-to-noise is improved. The cardiac rate is obtained based on the PhotoPlethysmoGraphy (PPG). We use LED as the light source and use photoelectric diode as the receiving tube. The LED and the photoelectric diode are on the different sides of the beam splitter prism and they form the optical system. The signal processing and display unit is composed by the signal processing circuit, data acquisition device and computer. The light emitted by the modulated LED is collimated by the lens and irradiates the measurement target through the beam splitter prism. The light reflected by the target is focused on the receiving tube through the beam splitter prism and another lens. The signal received by the photoelectric diode is processed by the analog circuit and obtained by the data acquisition device. Through the filtering and Fast Fourier Transform, the cardiac rate is achieved. We get the real time cardiac rate by the moving average method. We experiment with 30 volunteers, containing different genders and different ages. We compare the signals captured by this method to a conventional PPG signal captured concurrently from a finger. The results of the experiments are all relatively agreeable and the biggest deviation value is about 2bmp.

A lensless digital holographic tomography using not a filtered back projection method but a light back propagation method is proposed. In the proposed method, the phase distribution on the detector is used for a light propagation. On the contrary, in the conventional method, the phase information is used for a back projection. Owing to the propagation, the deflection from a true optical path is reduced in the proposed method. For the measurement of a specimen with a huge refraction angle, it is shown that our proposed method improves on measurement accuracy compared with a conventional filtered back projection method. Numerical simulations are given to confirm the feasibility of the proposed method.

Optical spectrometer of the Guillermo Haro astrophysical observatory (Mexico) exploits mechanically removable traditional static diffraction gratings as dispersive elements. There is a set of the static gratings with the slit-density 50 – 600 lines/mm and optical apertures 9 cm x 9 cm that provide the first order spectral resolution from 9.6 to 0.8 A/pixel, respectively, in the range 400 – 1000 nm. However, the needed mechanical manipulations, namely, replacing the static diffraction gratings with various resolutions and following recalibration of spectrometer within studying even the same object are inconvenient and lead to losing rather expensive observation time. We suggest exploiting an acousto-optical cell, i.e. the dynamic diffraction grating tunable electronically, as dispersive element in that spectrometer. Involving the acousto-optical technique, which can potentially provide electronic control over the spectral resolution and the range of observations, leads to possible eliminating the above-mentioned demerits and to improving the efficiency of analysis.

In this paper, we present a fast hologram pattern generation method to overcome accumulation problem of point source based method. Proposed method consists of two steps. In the first step, 2D projection of wave field for 3D object is calculated by radial symmetric interpolation (RSI) method to the multiple reference depth planes. Then in the second step, each 2D wave field is translated toward SLM plane by FFT based algorithm. Final hologram pattern is obtained by adding them. The effectiveness of method is proved by computer simulation and optical experiment. Experimental results show that proposed method is 3878 times faster than analytic method, and 226 times faster than RSI method.

Holographic optical correlator (HOC) is applicable in occasion where the instant search throughout a huge database is demanded. The primary advantage of the HOC is its inherent parallel processing ability and large storage capacity. The HOC’s searching speed is proportional to the storage density. This paper proposes a phase-encoding method in the object beam to increase the storage density. A random phase plate (RPP) is used to encode the phase of the object beam before uploading the data pages to the object beam. By shifting the RPP at a designed interval, the object beam is modulated into an orthogonal object beam to the previous one and a new group of database can be stored. Experimental results verify the proposed method. The maximum storage number of the data pages with a RPP at a fixed position can be as large as 7,500. The crosstalk among different groups of the databases can be unnoticeable. The increase in the storage density of the HOC depends on the number of the orthogonal positions from the different portions of a same RPP.

The integration of photonic antennas with radio over fiber (RoF) systems can serve high dense populated areas such as airports, shopping centers, dead-zone areas and tunnels. In this paper, we present an optical wireless communication downlink with a photonic antenna. Our proposed radio over fiber (RoF) system is to carry modulated orthogonal frequency division multiplexing (OFDM) signals with a 2.4 GHz radio frequency over a cost effective optical link. A comparison of using a photonic antenna as a passive and an active in the RoF system is presented. The active photonic antenna (APHA) is mounted at the end of the optical link to the photodiode as a package of a band-pass filter (BPF) and a radio frequency power amplifier. The photonic antenna scattering parameters are implemented into the optical system simulation tools with various fiber length and free space loss (FSL). The wireless link is implemented for a transmission distance up to 100 meters. The transmitted signal is fully carried over a radio frequency signal and then optically carried over a standard single mode fiber (SSMF). The measurements of the EIPR and SNR were done with 0 dBm RF input into the directly modulated laser (DML) for all the simulations. The results show that the analog optical wireless link is very suitable to carry the OFDM signals. Moreover, the active photonic antenna provides sufficient service for more than 30 meters compared to the passive antenna.

Optical filters are crucial elements in optical communications. The influence of cascaded filters in the optical signal will affect the communications quality seriously. In this paper we will study and simulate the optical signal impairment caused by different kinds of filters which include Butterworth, Bessel, Fiber Bragg Grating (FBG) and Fabry-Perot (FP). Optical signal impairment is analyzed from an Eye Opening Penalty (EOP) and optical spectrum point of view. The simulation results show that when the center frequency of all filters aligns with the laser’s frequency, the Butterworth has the smallest influence to the signal while the F-P has the biggest. With a -1dB EOP, the amount of cascaded Butterworth optical filters with a bandwidth of 50 GHz is 18 in 40 Gbps NRZ-DQPSK systems and 12 in 100 Gbps PMNRZ- DQPSK systems. The value is reduced to 9 and 6 respectively for Febry-Perot optical filters. In the situation of frequency misalignment, the impairment caused by filters is more serious. Our research shows that with a frequency deviation of 5 GHz, only 12 and 9 Butterworth optical filters can be cascaded in 40 Gbps NRZ-DQPSK and 100 Gbps PM-NRZ-DQPSK systems respectively. We also study the signal impairment caused by different orders of the Butterworth filter model. Our study shows that although the higher-order has a smaller clipping effect in the transmission spectrum, it will introduce a more serious phase ripple which seriously affects the signal. Simulation result shows that the 2nd order Butterworth filter has the best performance.

OFDM has been adopted in many high systems due to its high data rates and to its robust performance in fading channel. OFDM distributes the data among number of carriers which are called subcarriers. The subcarriers must be orthogonal to prevent the carrier from interfering to each other. Features such overcoming ISI (inter-symbol interference) and the complexity of Designing both receiver and transmitter made it ideal technique for both wired and wireless communication as long as optical communications. However, OFDM suffers from a defect called Peak Average power ratio (PAPR). APARP is crucial drawback that limits the way that OFDM functions and reducing or mitigating this factor in wireless and optical environment will help overcome and enhance the OFDM date rate. PAPR is the main cause of inter-carrier interference and high out-of-band power, and consequently Bit error rate BER. We investigate some of the techniques that mitigate the effect of PAPR. These techniques are merged together to provide a better PAPR reduction with the existing techniques. In this paper, we are proposing a new reduction algorithm to minimize the effect of the PAPR. The results and simulation are done in Optisystem V-11 and Matlab environment. These approaches will be applied on WiMAX application and the performances between the different techniques are examined.

Electro-optic logic is a paradigm which employs the optical switch network to perform the logical operation. The status of each switch in the optical network is determined by an electrical Boolean signal applied to it. The operation of each switch is independent of the operations of other switches in the network and the operation result propagates in the network at the speed of light. The overall latency of the logic circuit is very small and all switches perform their operations almost simultaneously. Therefore, the electro-optic logic has a very high operation speed. Silicon microring resonator is an attractive structure owing to its outstanding performances, such as compact size, ultra-low power consumption and CMOS-compatible process. Therefore, the electro-optic logic based on silicon microring switches is easy to realize large-scale integration and low-cost manufacture in a high-volume CMOS-photonics foundry. We have proposed and demonstrated two electro-optic logic circuits based on silicon microring switches including XOR/XNOR and AND/NAND. We also proposed the architectures to achieve encoder, decoder and half-adder, and demonstrated them with the thermo-optic effect. In this paper, we will review the recent research on electro-optic logic circuits based on silicon microring switches and introduce new development in this topic.

Matrix-vector multiplication is a fundamental operation in modern digital signal processing. Inspired by the intrinsic spatial parallelism of optics, many efforts have been made to develop optical apparatuses that can perform such a parallelizable operation. Here we report the proposal of an on-chip optical signal processor with the function of matrixvector multiplication, which is composed of laser-modulator array, multiplexer, splitter, microring modulator matrix and photodetector array. We fabricate a 4×4 microring modulator matrix on silicon-on-insulator (SOI) platform with complementary metal-oxide-semiconductor (CMOS)-compatible process. 8×10⁷ multiplications and accumulations (MACs) per second is implemented by such an on-chip microring modulator matrix and off-chip laser-modulator array, multiplexer and photodetector. The significant progress in integrated optoelectronics makes it possible to integrate all required functional optical devices and even the driving and controlling circuits on the same chip. Theoretical analysis is given to estimate the potential performance of such an integrated system, which is several orders of magnitude faster than current electrical digital signal processors.

One benefit of employing computer vision techniques to extract individual vehicles from a highway traffic scene is the abundance of networked, traffic surveillance cameras that may be leveraged as the input video. However, the acquisition sensors that are monitoring the highway traffic will have very limited quality. Additionally, video streams are heavily compressed, causing noise and, in some cases, visible artifacts to be introduced into the video. Further challenges are presented by external environmental and weather conditions, such as rain, fog, and snow, that cause video blurring or noise. The resulting output of a segmentation algorithm yields poorer results, with many vehicles undetected or partially detected. Our goal is to extract individual vehicles from a highway traffic scenes using super-resolution and the utilization of Gaussian mixture model algorithm (GMM). We used a speeded-up enhanced stochastic Wiener filter for SR reconstruction and restoration. It can be used to remove artifacts and enhance the visual quality of the reconstructed images and can be implemented efficiently in the frequency domain. The filter derivation depends on the continuous-discrete-continuous (CDC) model that represents most of the degradations encountered during the image-gathering and image-display processes. Then, we use GMM followed by the clustering of individual vehicles. Individual vehicles are detected from the segmented scene through the use of a series of morphological operations, followed by two-dimensional connected component labeling. We evaluate our hybrid approach quantitatively in the segmentation of the extracted vehicles.

A real-time system for illumination-invariant object tracking is proposed. The system is able to estimate at high-rate the position of a moving target in an input scene when is corrupted by the presence of a high cluttering background and nonuniform illumination. The position of the target is estimated with the help of a filter bank of space-variant correlation filters. The filters in the bank, adapt their parameters according to the local statistical parameters of the observed scene in a small region centered at coordinates of a predicted position for the target in each frame. The prediction is carried out by exploiting information of present and past frames, and by using a dynamic motion model of the target in a two-dimensional plane. Computer simulation results obtained with the proposed system are presented and discussed in terms of tracking accuracy, computational complexity, and tolerance to nonuniform illumination.

Coded aperture spectral imaging is a new system to captures multiframes images and reconstructs them into spectral image cube based on compressive sensing theory (CS). However, using dynamic transformed coded aperture pattern can cause two primary problems, firstly the whole exposure procedure needs to be staring on the same surface feature which is depended on a high quality stable platform; secondly the coded aperture’s transformation might reduce the system’s stability. To avoid these problems without a loss of information for precise reconstruction, in the paper we propose dividing the single image panel into encoding spatial overlapped sub-districts. We design a pushbroom scan pattern to ensure each sub-district have enough sampling measurements. In each sub-district, we infer its measurement matrix can satisfy the sparsely requirements needed for accurate estimation and final reconstruction with CS sampling. Considering with efficiency and accuracy, we design a orthogonal self-loop coding mask (lines irrelevant) to guarantee the coding are irrelevant among distinct snapshot of the same scene. The simulation experiment reveals the design helping reconstruct the scene spectral cube with high throughput and resolution.

The holographic data storage system (HDSS) is a page-oriented storage system with advantages of great capacity and high speed. The page-oriented recording breaks the tradition of the optical storage of one-point recording. As the signal image is retrieved from the storage material in the HDSS, various noises influences the image and then the data retrieve will be difficultly from the image by using the thresholding method. For progressing on the thresholding method, a recognition method, based on the structural similarity, is proposed to replace the thresholding method in the HDSS. The recognition method is implemented that the image comparison between the receive image and reference image is performed by the structural similarity method to find the most similar reference image to the received image. In the experiment, by using recognition method, the bit error rate (BER) results in 26% decrease less than using the thresholding method in the HDSS. Owing to some strong effects, such as non-uniform intensity and strong speckle, still influencing on the received image, the recognition method is seemed to be slightly better than thresholding method. In the future, the strong effects would be reduced to improve the quality of the receive image and then the result of using the recognition method may be vastly better than the thresholding method.

In this paper the robustness of a recently proposed image watermarking scheme is investigated, namely the Double Random Phase Encoding spread-space spread-spectrum watermarking (DRPE SS-SS) technique. In the DRPE SS-SS method, the watermark is in the form of a digital barcode image which is numerically encrypted using a simulation of the optical DRPE process. This produces a random complex image, which is then processed to form a real valued random image with a low number of quantization levels. This signal is added to the host image. Extraction of the barcode, involves applying an inverse DRPE process to the watermarked image followed by a low pass filter. This algorithm is designed to utilize the capability of the DRPE to reversibly spread the energy of the watermarking information in both the space and spatial frequency domains, and the energy of the watermark in any spatial or spatial frequency bin is very small. The common geometric transformations and signal processing operations are performed using both the informed and the blind detections for different barcode widths and different quantization levels. The results presented indicate that the DRPE SS-SS method is robust to scaling, JPEG compression distortion, cropping, low pass and high pass filtering. It is also demonstrated that the bigger the barcode width is, the lower the false positive rate will be.

Images obtained through charged coupled device (CCD) cameras in the National Ignition Facility (NIF) are crucial to precise alignment of the 192 laser beams to the NIF target-chamber center (TCC). Cameras in and around the target chamber are increasingly exposed to the effects of neutron radiation as the laser power is increased for high energy fusion experiments. NIF was carefully designed to operate under these conditions. The present work examines the degradation of the measured TCC camera position accuracy resulting from the effects of neutron radiation on the sensor and verifies operation within design specifications. Both synthetic and real beam images are used for measuring position degradation. Monte Carlo simulations based on camera performance models are used to create images with added neutron noise. These models predict neutron induced camera noise based on exposure estimates of the cumulative single-shot fluence in the NIF environment. The neutron induced noise images are used to measure beam positions on a target calculated from the alignment images with the added noise. The effects of this noise are also determined using noise artifacts from real camera images viewing TCC to estimate beam position uncertainty.

Data is commonly moved through optical fiber in modern data centers and may be stored optically. We propose an optical method of data mining for future data centers to enhance performance. For example, in clustering, a form of unsupervised learning, we propose that parameters corresponding to information in a database are converted from analog values to frequencies, as in the brain's neurons, where similar data will have close frequencies. We describe the Wilson-Cowan model for oscillating neurons. In optics we implement the frequencies with micro ring resonators. Due to the influence of weak coupling, a group of resonators will form clusters of similar frequencies that will indicate the desired parameters having close relations. Fewer clusters are formed as clustering proceeds, which allows the creation of a tree showing topics of importance and their relationships in the database. The tree can be used for instance to target advertising and for planning.

A backscattering model of average signal power function for laser radar range imagery obtained by a short pulse laser for a coarse cone is presented in this paper. This model can analyze the laser range profile and range imaging which relate the average power seen by the receiver with laser pulse, target shape, optical scattering properties of surface material, incidence angle and other factors. Simulation of the laser range profile and range imaging of a coarse cone is given. Based on the results of the simulated model and theoretical analysis, the cone can be identified. The model can be used for demonstration of 3D laser radar system and can also be used to generate library of model data sets for automatic target recognition.

Coupled-resonator-induced transparency (CRIT) effect has been widely studied in parallelly coupled double microring resonators (MRRs), and various applications based on the CRIT effect have been demonstrated. We report the proposal and demonstration of a directed logic circuit with the functions of XOR and XNOR using CRIT. Two electrical signals applied to two coupled MRRs represent two operands of the logic operations, and the operation results are represented by the output optical signal. As proof-of-concept, the thermo-optic modulation scheme is employed with an operating speed of 10 kbps.

This paper proposes a system design that integrates CO-OFDM with WDM to reach a data rate of 400 Gbits/s over 1000 Km Single Mode Fiber (SMF). The 400 Gbits/s signal is generated by multiplexing eight OFDM with 50 Gbits/s for each OFDM. We present the performance of CO- OFDM WDM back to back design by measuring the BER and the OSNR (Optical Signal to Noise Ratio) and the constellation diagram of each user. We will also show the performance of CO-OFDM WDM for 1000 Km SMF by measuring the BER and the OSNR of different WDM channels and studying the constellation diagram of each user.

Phenanthrenequinone (PQ) doped poly(methyl methacrylate) (PMMA) photopolymer material has been studied extensively due to the growing interest in application involving photopolymers. However, to progress the development a more physical material model has become necessary. In this article, a kinetic model is developed, which includes: (i) the time varying photon absorption, including the absorptivity of a second absorber, i.e., the singlet excited state of PQ, (ii) the recovery/regeneration and the bleaching of the excited state PQ, (iii) the nonlocal effect, and (iv) the diffusion effects of both the ground and excited state PQ molecules and of the methyl methacrylate (MMA). A set of rate equations are derived, governing the temporal and spatial variations of each chemical component concentration. The validity of the proposed model is examined by applying it to fit experimental data for PQ-PMMA layers containing three different initial PQ concentrations, i.e., 1 mol.%, 2 mol.% and 3 mol.%. The effect of different exposure intensities is also examined. Material parameters are extracted by numerically fitting experimentally measure normalized transmission curves and the refractive index modulation growth curve using the theoretical models.

Based on the previous study of the time varying photon absorption effects, the behavior of four different photosensitizers in an AA/PVA photopolymer material has been further examined by using the developed 1-D Nonlocal Photopolymerization Driven Diffusion (NPDD) model. In order to characterize the photosensitizers precisely, holographic illuminations with different spatial frequencies are applied. Material parameters, i.e., the nonlocal response parameter, σ, the diffusion rate of monomer, Dm, the chain initiation kinetic constant, ki, and the termination rate, kt, are extracted by numerically fitting experimentally measure the refractive index modulation growth curve using the theoretical models. In this paper, the four different photosensitizers under investigation are Erythrosin B; Eosin Y; Phloxine B; Rose Bengal.

The structured light technique is useful to evaluate the topography of an object. By using the Fourier transform, the phase of a fringe pattern is obtained from a single image. With the phase information and the sensibility vector of the optical system, the value z(x, y) at each point of the object can be determined. It is known that color is a subjective sensation, and it changes depending on the observer. In order to make an association of real color and texture, it is necessary to calibrate and profile the optical devices involved in the process. Thus, we ensure that the color detected by a camera is the same displayed on the monitor and perceived by the observer, so it is possible to associate the color of the target object in addition to the evaluation of topography. On the other hand, 3D visualization is possible by using a stereoscopic system that provides two different images of the same object (one for each eye). One possible technique is that known as the anaglyph method, based on the binocular disparity of two images obtained with different color filters. Each one of the images is taken with complementary colors (red-blue or red-green), and the tri-dimensional shape can be seen through the use of special glasses; this way, each eye sees an image from its own angle. Object topography is obtained with the fringe projection technique, and then one image is selected and pseudo colored; then, the second image is taken, slightly changing the perspective of the tridimensional display and pseudo coloring it with a complimentary color. A computational algorithm is developed to evaluate and visualize the object in real time.

Different modulation formats may be required in different optical communication networks. Format conversion from intensity format to phase format is necessary to ensure the functions between long-haul transmission networks and metropolitan area networks. Cross-phase modulation (XPM) in silicon waveguides provides a promising way to realize all-optical integrated format conversion since a nonlinear phase shift is induced to the probe by the incident signal power. An on-off keying (OOK) signal can be converted to differential phase-shift keying (DPSK) signal if nonlinear phase shift of π is achieved. We numerically investigate the nonlinear phase shift caused by XPM in silicon waveguides by considering the influences of the walk-off effect, group-velocity dispersion, and nonlinear losses including two-photon absorption (TPA) and free-carrier absorption (FCA). The nonlinear phase shift is tried to be enhanced through waveguide design and wavelength management. The walk-off effect can be minimized by carefully choosing the zero dispersion wavelength of the used silicon waveguide and setting the signal and probe wavelengths symmetrically. Low and flat dispersion is beneficial to acquiring a large nonlinear phase shift. TPA and FCA will greatly reduce the nonlinear phase shift obtained from XPM and they should be effectively suppressed in order to realize high-quality format conversion.

It is believed that asymmetric cryptosystem based on phase-truncated Fourier transform has immunity against knownplaintext attack. However, generation of two asymmetric keys is possible, if plaintext-ciphertext pair is known. In this paper, we show that amplitude- and phase-truncation-based asymmetric cryptosystem is vulnerable to known-plaintext attack. The decryption keys are generated with the help of modified Gerchberg-Saxton phase retrieval algorithm from known-plaintext and cipher-text. The first key is generated from known-plaintext and the second key is generated from the cipher-text. With the help of the generated keys, the encrypted image in one domain is decrypted successfully in another domain. The domains used for this study are Fourier, Fresnel, fractional Fourier or gyrator domain. The vulnerability is proved through the results of computer simulation.

Recently the possibility to record phase diffractive optical elements (DOEs) onto photopolymers has been explored. Two of their properties when they are illuminated are useful to this goal: the relief surface changes and the refractive index modifications. The recording intensity distribution with a sinusoidal profile is the easiest profile to record in a holographic recording material, i.e. it can be obtained by the simple interference of two plane wave beams or alternatively using a spatial light modulator. This second method is more flexible and opens the possibility to record a wide range of diffractive elements such as binary, blazed gratings, diffractive lenses, etc. Sharp profiles may as well be recorded. In general they present a clear smoothing of the edges due to various reasons: the cut-off frequency (a low pass filtering) of the optical system, quality of the spatial light modulation, inhibition period, finite size of polymer chains, monomer diffusion, and non-linearities in the recording process. In this work we have analyzed the importance of some of these aspects of the photopolymer and the experimental set-up in order to record high quality DOEs. The photopolymer analyzed is based on polyvinylalcohol/acrylamide. To achieve this goal we have used a diffusion model to simulate the DOE’s recording with different recording intensities distributions.

Optical diffraction fields have in general a spatial complex structure and some times can generate focusing regions, in this work we describe the focusing region associated with highly symmetric transmittances, analyzing its associated phase function. We show that generic features can be studied from a differential equation for a focusing geometry, which is obtained through angular representation for diffraction fields, according to the choice of the parameters involved, the diffraction field presents a new focusing region whose geometry and spatial evolution can be described with the only analysis of the phase singularities avoiding the integral representation.

The paper reviews the recent research progresses of vision measurement. The general methods of the depth detection used in the monocular stereo vision are compared with each other. As a result, a novel bifocal imaging measurement system based on the zoom method is proposed to solve the problem of the online 3D measurement. This system consists of a primary lens and a secondary one with the different focal length matching to meet the large-range and high-resolution imaging requirements without time delay and imaging errors, which has an important significance for the industry application.