Improved holographic particle sizing by using absolute values of the wavelet transform

A new method for sizing particle from in-line particle holograms by using absolute values of the wavelet transform is proposed in order to improve accuracy in measurements. The proposed method provides direct calculation of the particle size by using spatial frequency information of a chirp signal at minima position of an envelope function. Simulation and experimental results are presented.     

数字全息中再现像分离问题的研究

详细分析了数字全息的再现像分离条件,指出数字全息和普通全息的再现像分离条件之间的区别,同时也讨论了再现条件对数字全息记录光路的要求,同时给出一种能部分避免再现像重叠的处理方法,并做出相应的实验验证.     

An Area Optimization Method for Digital Filter Design

In this paper, we propose an efficient design method for area optimization in a digital filter. The conventional methods to reduce the number of adders in a filter have the problem of a long critical path delay caused by the deep logic depth of the filter due to adder sharing. Furthermore, there is such a disadvantage that they use the transposed direct form (TDF) filter which needs more registers than those of the direct form (DF) filter. In this paper, we present a hybrid structure of a TDF and DF based on the flattened coefficients method so that it can reduce the number of flip‐flops and full‐adders without additional critical path delay. We also propose a resource sharing method and sharing‐pattern searching algorithm to reduce the number of adders without deepening the logic depth. Simulation results show that the proposed structure can save the number of adders and registers by 22 and 26%, respectively, compared to the best one used in the past.     

Numerical reconstruction of an infrared wavefront utilizing an optical phase modulation device

We utilize nitroanisole, that absorbs infrared (IR) radiation as heat, as an optical modulation device based on a thermal process. The nitroanisole exhibits a thermal lens effect, i.e. a temperature dependent refractive index. Hence, the nitroanisole can induce phase modulation to visible light, in direct response to intensity of the incident IR radiation. The proposed method can be used to obtain the phase modulation distribution that corresponds to the IR intensity distribution, i.e. the IR hologram itself, on the nitroanisole by examining the phase map of visible light that is modulated upon passing through the nitroanisole. The IR wavefront can be reconstructed by calculating extracted IR holograms through the Fresnel transform. It is verified that both the amplitude and the phase of the IR wavefront can be reconstructed accurately by proposed method.     

Quantitative vibration amplitude measurement with time-averaged digital speckle pattern interferometry

A new method of using time-averaged digital speckle pattern interferometry for the quantitative measurement of vibration amplitude was developed. Signal processing techniques especially the Hilbert transformation for quantitative evaluation of the Bessel fringes obtained in time-averaged digital speckle pattern interferometry were explored. The quadrature signal after Hilbert transformation is equivalent to a 90° phase-shifted interferogram for a monotonically increasing or decreasing phase function. An algorithm was developed for Bessel fringe contrast enhancement and phase extraction. The techniques were tested numerically and experimentally. Sub-fringe quantification of the time-averaged vibration fringes is realised with the proposed method. Compared with the commonly used phase shift method which requires a minimum of two images for image processing, this method requires only one fringe pattern for data extraction.     

一种RISC单片机的分块结构寄存器堆

介绍了一种用于ＲＩＳＣ单片机ＰＩＣ１６Ｃ５７的寄存器堆，讨论了为降低功耗所采用的分块结构，详细说明了译码逻辑、ＳＲＡＭ单元、读／写电路和文件选择寄存器等电路的形式及其工作原理     

一种多输入队ATM交换结构

本文提出一种多输入排队ＡＴＭ交换结构和相应的输出冲突解决方法，它可以使交换网络避免输入队固有的排头阻塞，从而使网络在不增加运行速率的情况下，可达到输出排队的性能。文中介绍了冲突解决办法及其实现技术，说明它可方便地在高速网中实现。     

数字程控交换机与专网中的多媒体通信

本文以一个多媒体通信应用VISIT为实例,介绍了多媒体通信在数字程控交换机及专网中的应用情况。     

新颖的基于小波变换的数字水印方案

随着计算机网络技术与多媒体技术的快速发展，数字产品的版权保护已经成为信息技术领域中最重要的问题之一，提出了一种新颖的基于离散小波变换的数字水印方案，该方案利用改进的Pacthwork算法，将水印嵌入到LL子带中，水印信号在解码过程中无需使用原始图像可快速地重嵌入，该算法利用BCH码来降低误码率，应用所提出的算法，把一个32个字符的水印嵌入到图像中，实现结果表明水印是不可察觉的，经过JPEG有损压缩，低通与中值滤波等图像处理操作后仍是鲁棒的。     

Multiresolution coding techniques for digital television: A review

Multiresolution decompositions for video coding are reviewed. Both nonrecursive and recursive coding schemes are considered. In nonrecursive schemes, it is shown that pyramid structures have certain advantages over subband or wavelet techniques, and a specific spatiotemporal pyramid coding of HDTV is discussed in some detail. It is shown that recursive, DPCM like schemes will incur a slight loss of optimality due to a restricted form of prediction if multiresolution decomposition with compatible decoding is required. Compatibility and transmission issues are also discussed. Multiresolution transmission for digital broadcast TV is introduced. This, when combined with multiresolution source coding, achieves spectrum efficiency, robustness and graceful degradation under channel impairments.Invited PaperWork supported in part by the National Science Foundation under grants ECD-88-11111, MIP-90-14189 and Bell Communications Research.Work supported by the National Science Foundation under grants ECD-88-11111. K.M. Uz is now with David Sarnoff Research Center in Princeton, NJ 08543.