Extended depth of field with a nonlinear silver-halide emulsion detector

Presented here are experimental results of an extended depth-of-field (EDF) system using film to record the image. The EDF system used is an application of wave-front coding. A phase mask is placed in the aperture stop of the lens to code the image data; then digital signal processing is used to decode the image. Wave-front coding is based on linear systems theory, but film is not a linear medium. An extra step of linearization is then needed to apply the technique. Both nonlinear and linearized results are shown, as is a test image that demonstrates the success of the technique for nonlinear media.     

Extended coding for optical array logic

We present extended coding for optical array logic (OAL) to avoid the marginal effect. The marginal effect is defined as an effect caused by the finite size of the image region, and it is a problem in massively parallel processing by OAL. OAL is a paradigm of optical computing suitable for optical implementation utilizing image coding and discrete correlation. To avoid the marginal effect in the context of OAL, we propose a new coding rule and consider possible operations with this coding. With extended coding, binary data can be identified from background with the same number of pixels as that used in the original OAL. Simulation results of the operations verify the correctness of the proposed technique.     

光电编码角位移传感用于三表集抄系统

本文介绍了用于水、电、气三表集抄系统的光电编码角位移传感技术。光电编码器测量出数字轮当前角度,它有 20 个编码,采用 5 个发射管、5 个接收管和 2 个码道的设计方案。直读表具的数据通过集中器采集到管理系统,实现了三表的集抄。     

Three-dimensional image compression with integer wavelet transforms

A three-dimensional (3-D) image-compression algorithm based on integer wavelet transforms and zerotree coding is presented. The embedded coding of zerotrees of wavelet coefficients (EZW) algorithm is extended to three dimensions, and context-based adaptive arithmetic coding is used to improve its performance. The resultant algorithm, 3-D CB-EZW, efficiently encodes 3-D image data by the exploitation of the dependencies in all dimensions, while enabling lossy and lossless decompression from the same bit stream. Compared with the best available two-dimensional lossless compression techniques, the 3-D CB-EZW algorithm produced averages of 22%, 25%, and 20% decreases in compressed file sizes for computed tomography, magnetic resonance, and Airborne Visible Infrared Imaging Spectrometer images, respectively. The progressive performance of the algorithm is also compared with other lossy progressive-coding algorithms.     

波前编码系统中相位掩膜板的新设计

波前编码技术能扩大非相干光学成像系统的景深。根据传统相位掩膜板的设计原理,从两个方面对原有的相位掩膜板农达式进行扩展。由此提出了两种新的设计方案：“多项式”方案和“高次方”方案。前者是在原有的公式中加入了x平方项,而后者是将原有的高次方指数拓展到小数形式。将这两种新系统进行模拟计算,得到了相关的调制传递函数（MTF）数据和三维图,结果显示MTF随离焦量变化很小（当u=1时,均方差分别为0．0027和0．0021）,而且不会出现零值,跟传统方案MTF差值分别在0．05和0．04以内。由此说明新方案也能实现扩大光学系统景深的目的。     

Hybrid algorithm based on improved extended shifting bottleneck procedure and GA for assembly job shop scheduling problem

With the makespan as the optimisation goal, we propose a hybrid solving method that combines improved extended shifting bottleneck procedure (i-ESB) and genetic algorithm (GA) for the assembly job shop scheduling problem (AJSSP). Hybrid genetic algorithm (HGA) uses a GA based on operation constraint chain coding to achieve global search and a local search based on an i-ESB. In the design of i-ESB, an extended disjunctive graph model (EDG) corresponding to AJSSP is presented. The calculation method of the operation head and tail length based on EDG is studied, as well as the searching method of key operations. The Schrage algorithm with disturbance is used to solve the single-machine scheduling subproblem. The selection criterion for bottleneck machines is increased. A greedy bottleneck machine re-optimisation process is designed. The effectiveness and superiority of the proposed algorithm are verified by testing and analysing the relevant examples in the literature.     

Investigation of an optical multiple PPM link over a highly dispersive optical channel

A performance analysis of (X/Y) multiple pulse position modulation (PPM) systems, in which X denotes the number of data slots and Y the number of pulses, operating over a plastic optical fibre channel has been described. The effects of receiver noise and channel dispersion are accounted for and the manner in which the erasure, wrong-slot and false-alarm errors affect the system performance is examined. The receiver/decoder uses slope detection and a maximum likelihood sequence detector. As the analysis of any (x/y) multiple PPM system is extremely time-consuming, a novel automated solution was designed to predict the equivalent pulse code modulation (PCM) error rates of specific sequences and to simplify the task. A measure of coding quality that accounts for efficiency of coding and bandwidth expansion has also been proposed. Using this measure, original results show that a (12/6) system is the most efficient for a wide range of bandwidths.     

Optimal classification methods for diagnosing latent skills and misconceptions for option-scored multiple-choice item quizzes

Behaviormetrika - The paper’s extended Diagnostic Classification Modeling setting assumes (a) nominal item (question) coding, thus including multiple-choice (MC) items, and (b)...     

Pseudo-orthogonal frequency coded wireless SAW RFID temperature sensor tags

SAW sensors are ideal for various wireless, passive multi-sensor applications because they are small, rugged, radiation hard, and offer a wide range of material choices for operation over broad temperature ranges. The readable distance of a tag in a multi-sensor environment is dependent on the insertion loss of the device and the processing gain of the system. Single-frequency code division multiple access (CDMA) tags that are used in high-volume commercial applications must have universal coding schemes and large numbers of codes. The use of a large number of bits at the common center frequency to achieve sufficient code diversity in CDMA tags necessitates reflector banks with >30 dB loss. Orthogonal frequency coding is a spread-spectrum approach that employs frequency and time diversity to achieve enhanced tag properties. The use of orthogonal frequency coded (OFC) SAW tags reduces adjacent reflector interactions for low insertion loss, increased range, complex coding, and system processing gain. This work describes a SAW tag-sensor platform that reduces device loss by implementing long reflector banks with optimized spectral coding. This new pseudo-OFC (POFC) coding is defined and contrasted with the previously defined OFC coding scheme. Auto- and cross-correlation properties of the chips and their relation to reflectivity per strip and reflector length are discussed. Results at 250 MHz of 8-chip OFC and POFC SAW tags will be compared. The key parameters of insertion loss, cross-correlation, and autocorrelation of the two types of frequency-coded tags will be analyzed, contrasted, and discussed. It is shown that coded reflector banks can be achieved with near-zero loss and still maintain good coding properties. Experimental results and results predicted by the coupling of modes model are presented for varying reflector designs and codes. A prototype 915-MHz POFC sensor tag is used as a wireless temperature sensor and the results are shown.     

Coded excitation for synthetic aperture ultrasound imaging

Peak acoustic power limits the signal-to-noise ratio (SNR) of real-time ultrasound images. For most conventional scan formats, however, the average power is well below heating limits. This means the SNR can be significantly increased using coded excitation. A coded system transmits a broadband, temporally elongated excitation pulse with a finite time-bandwidth product. The received signal must be decoded to produce an imaging pulse with improved SNR resulting from the higher average power in the elongated excitation. Decoding can produce significant range side lobes, however, greatly reducing image quality. All practical coding designs, therefore, represent a trade-off between SNR gain and range side lobes. A specific coding scheme appropriate for synthetic aperture imaging is presented. A 14.5 dB SNR improvement with acceptable range side lobes is demonstrated on a forward-looking imaging system appropriate for intravascular applications.     

Environment conscious manufacturing edited by S.M. Gupta and A.J.D. Lambert

The dynamic facility layout problem (DFLP) aims to minimise the sum of handling and re-layout costs by devising an individual layout for each distinctive production period. In this paper, a hybrid particle swarm optimisation (HPSO) algorithm is proposed to find near-optimal solutions of DFLP. We use a coding and decoding technique that permits a one to one mapping of a solution in discrete space of DFLP to a PSO particle position in continuous space. The proposed PSO will further use this coding technique to explore the continuous solution space. For further enhancement, the proposed PSO is hybridised with a simple and fast simulated annealing. The developed algorithm is capable of being extended to more general cases although equal area machines and standardised handling equipments with identical unit costs are assumed for the time being. Computational results show the efficiency of the proposed algorithm compared to other heuristics.     

Coding for compressive focal tomography

We consider the capabilities and limits of strategies for single-aperture three-dimensional and extended depth of field optical imaging. We show that reduced spatial resolution is implicit in forward models for light field sampling and that reduced modulation transfer efficiency is intrinsic to pupil coding. We propose a novel strategy based on image space modulation and show that this strategy can be sensitive to high-resolution spatial features across an extended focal volume.     

改进遗传算法解决柔性作业车间调度问题

柔性作业车间调度问题是经典作业车间调度问题的扩展,它允许工序在多台机器中的任意一台上加工.针对柔性作业车间调度问题的特点,提出一种扩展的基于工序的编码及其主动调度的解码机制,并设计一种初始解产生机制和两种有效的交叉和变异操作.为了克服传统遗传算法早熟和收敛慢的缺点,设计了精英解保留策略和子代产生模式结合的改进遗传算法应用于该调度问题.最后运用提出的算法求解基准测试问题验证算法的有效性.     

A method of obtaining the radiation modulation function in an optoelectronic digital angle converter using a radon transform

A method of obtaining the radiation modulation function in the optical channel of practical optoelectronic digital angle converters using the apparatus of analytical geometry together with a local radial Radon transform is considered. The majority of the instrumental errors that arise when manufacturing and assembling the optomechanical unit are taken into account. The method can be extended to a wide class of optical coding devices and has practical applications.     

Video Transmission for Third Generation Wireless Communication Systems

This paper presents a twin-class unequal protected video transmission system over wireless channels. Video partitioning based on a separation of the Variable Length Coded (VLC) Discrete Cosine Transform (DCT) coefficients within each block is considered for constant bitrate transmission (CBR). In the splitting process the fraction of bits assigned to each of the two partitions is adjusted according to the requirements of the unequal error protection scheme employed. Subsequently, partitioning is applied to the ITU-T H.263 coding standard. As a transport vehicle, we have considered one of the leading third generation cellular radio standards known as WCDMA. A dual-priority transmission system is then invoked on the WCDMA system where the video data, after being broken into two streams, is unequally protected. We use a very simple error correction coding scheme for illustration and then propose more sophisticated forms of unequal protection of the digitized video signals. We show that this strategy results in a significantly higher quality of the reconstructed video data when it is transmitted over time-varying multipath fading channels.     

Application of the complex variable boundary element method to solving potential problems in doubly connected domains

The complex variable boundary element method (CVBEM) developed by Hromadka for the solution of potential problems in simply connected domains is extended to the solution of heat conduction problems in doubly connected domains. A cut is made in the doubly connected domain, and it was found that the complex potentials along the cut do not cancel out but result in a complex stream function that plays the role of perturbation in the nodal equations. Cauchy–Riemann conditions are used to derive additional equations which relate the stream functions and the boundary heat fluxes and potentials when Neumann and Robin conditions are imposed on the boundaries. The resulting nodal equations are expressed in matrix form, and coding rules and methods for checking the matrix elements are developed. Three solution methods (implicit, explicit and hybrid) are described, and by means of examples, the efficacy of these methods is discussed and compared.     

Manchester encoded bandpass sigma-delta modulation for RF class D amplifiers

An analysis of a continuous-time bandpass sigma-delta modulator in a configuration with an upconverter is given for a RF class D amplifier application. The upconverter multiplies the modulator pulse train with a synchronised clock signal and maps each modulator bit to an integer multiple k of a (+1, -1) or (-1, +1) pattern depending on the sign of the modulator bit. The upconversion is equivalent to an extension of Manchester encoding, which is usually defined for k=1. The analysis focuses on evaluating the impact of upconversion on the modulator coding efficiency and the average pulse period. A design equation is derived, which shows that coding efficiency is dependent only on the upconversion frequency ratio, while the average pulse period depends only on k. The equations provide a designer with a way of evaluating the trade-offs in the amplifier system and show that encoding with k=1 is the most efficient configuration for maximising coding efficiency and minimising switching power loss     

Three-dimensional complex image coding using a circular Dammann grating

Recently, optical image coding using a circular Dammann grating (CDG) has been proposed and investigated. However, the proposed technique is intensity based and could not be used for three-dimensional (3D) image coding. In this paper, we investigate an optical image coding technique that is complex-amplitude based. The system can be used for 3D image coding. The complex-amplitude coding is provided by a circular Dammann grating through the use of a digital holographic recording technique called optical scanning holography. To decode the image, along the depth we record a series of pinhole holograms coded by the CDG. The decoded reconstruction of each depth location is extracted by the measured pinhole hologram matched to the desired depth. Computer simulations as well as experimental results are provided.     

基于Pattern时延差编码体制的4信道水声通信

采用Pattern时延差编码(PDS)通信体制,研究了4通信信道水声通信技术。通信系统利用信息码元的时延差值进行时延编码,采用码元的多种不同波形(Pattern)来进行码元分割,另外还采用频率分割来划分通信信道。其优点是可有效对抗水声多途干扰并实现高速通信,通信速率达到1200bit/s。提出依据最小均方误差准则,利用波形相似性来联合估计两个信道的时延差值。通过大量海洋信道仿真实验,验证了PDS体制具有高通信速率和高可靠性。     

Multichannel sampling schemes for optical imaging systems

We introduce a framework of focal-plane coding schemes for multichannel sampling in optical systems. A particular objective is to develop an ultrathin imager without compromising image resolution. We present a complete f/2.1 optical system with a thickness of 2.2 mm. The resolution is maintained in the thin optical system by an integrated design of the encoding scheme, the process of making the coding elements, and the decoding algorithms.