一种基于人眼视觉特性的图像EZW算法

在对嵌入零树小波编码(Embedded Zero-tree Wavelets Encoding,EZW)算法研究的基础上,利用人眼的视觉特性(Human visual system,HVS),提出一种基于小波系数的嵌入零树小波编码算法,其主要包括对小波图像的低频子带(LLi)进行单独DPCM编码;抛弃最高频对角方向子带(HH1),不进行编码;根据人眼的视觉特性,对各子带分配不同的比特数进行零树量化,最后用游程编码实现输出.实验结果表明,此方法是一种比较有效的编码方法.     

基于小波变换的图像压缩

给出了使用二维小波变换进行图像压缩的原理和实例，提出了结合小波变换零树压缩和量化编码的新方法，小波分解后，仅保留图像最有用的部分，即低频成分，对三个高频部分强制为0，然后再对低频部分量化编码。该方法简便易行，压缩比高，效果极显著。     

一种适用于遥测系统的小波零树编码算法及其硬件实现

提出了一种基于LZC算法的改进无链表小波零树编码算法,与SPIHT算法比较大大降低了所需内存容量,并在Matlab上对其进行了仿真验证,仿真结果证明PSNR值比原LZC算法提高大约1dB左右。并给出该算法基于FPGA的VLSI结构。该结构在QuartusⅡ上进行功能仿真并综合通过。     

寻的头中扩大视场和减小图像模糊的装置

对一种常见的速率稳定的红红外寻的头作了改进，可得到了较大的视场，也大大减少了图像的模糊。本改进采用了装在寻的头传感器光学部件前头的作旋转运动的圆形光楔。将由寻的头传感器的圆周运动产生的主扫描矢量与由这块光楔转动产生的次扫描矢量合成，即可得到一种扫描图案，其总的视场要比只有传感器时更宽，同时还有偶然的零或接近零的空间扫描速度点，在这些点上即可采集到很少或没有图像模糊缺陷的“快拍”数据。     

多媒体信息压缩技术

针对多媒体信息压缩技术,介绍了静态图象压缩标准JPEG中编码器、解码器和交换格式3种元素的定义,编码类型及基于DCT编码,无失真编码和熵编码的结构;运动视频和音频压缩标准MPEG的概述及其视频压缩算法描述,音频压缩的编码和解码。最后介绍了统计式压缩Huffman方法和字典式压缩LZ78方法的举例,及常用的ARJ、PKZIP／PKUZIP和WinZIP等压缩软件。     

基于内容特征的视频半脆弱水印方案

本文提出一种基于内容的MPEG-Ⅰ/Ⅱ格式视频特征编码算法,其基本思想是采用离散余弦变换(DCT)变换域中不同8×8 块之间DCT能量关系来构造特征码.在此基础上给出了视频半脆弱水印方案,将内容特征码生成方法和水印算法有机地结合在一起.特征码具有"半脆弱"特性,即它对于可接受的"内容保持"修改具有鲁棒性,而对常见的"内容篡改"性修改具有敏感性.另外由于DCT系数块能量的主要部分集中在低频部分,这使得可以用低频部分来生成特征码,用高频部分来嵌入水印.实验结果验证了算法的有效性.     

一种改进的嵌入式零树小波编码方法

文中详细介绍了嵌入式零树小波编码,并分析了嵌入式零树小波编码的不足。针对其不足,提出了一种改进的编码方法。最后通过MATLAB7.0实验仿真,实验结果证明了改进算法的有效性。     

基于Matlab环境的JPEG图像压缩算法

压缩是多媒体技术得到长足发展的关键技术,而图像是多媒体信息的重要组成部分。针对图像压缩问题,分析了JPEG图像压缩系统的原理,提出了一种基于DCT的JPEG图像压缩技术,并在Matlab环境下实现了编码和解码的几个关键步骤,演示了一幅图像压缩后的效果。     

基于AMESim的DCT换挡过程仿真

在研究DCT动力学模型基础上,分析DCT车辆换挡过程．利用仿真软件AMESim建立DCT传动系统动力学模型,并进行仿真研究．研究结果表明：在DCT换挡过程中,随着滑磨时间的增加,冲击度逐渐减小,滑磨功逐渐增加,并且在惯性相阶段产生最大的冲击度．这对研究DCT换挡品质,提高车辆的换挡平顺性,为DCT在车辆上进行更深入的研究和发展提供了理论依据．     

基于小波变换和零树编码的无人机图像压缩

针对傅里叶变换的不足，介绍了小波变换，详细分析了嵌入式零树小波编码方法。采用bior3．7对图像woman进行单层分解，将原始图像与分解后低频和高频信息图像进行对比，清晰地看出图像的能量主要集中于低频系数，而高频系数主要是图像的细节信息。     

WT DCT算法及实现

小波变换可获得高的压缩率，而离散余弦变换可使能量更加集中。本文中，作者通过这两种变换的结合使用，得到高的压缩率，并设计了硬件实现系统。     

超大像素航空相机图像压缩算法的研究与应用

以超大像素航空CCD数码相机的研究与应用为背景,讨论了JPEG标准压缩算法.针对相机的实时传输系统,研究了基于JPEG标准的自适应量化表的快速压缩算法,并应用多线程技术实现了该算法.计算结果证明了该方法的有效性和可行性.     

声呐数据实时压缩算法性能分析

在反水雷领域,声呐探测技术作为主要的探雷手段,其探测数据显得尤为重要。由于声呐数据量大,并且许多探测数据相当珍贵,因此实时的存储与传输声呐数据成为急待解决的关键问题。对声呐数据的实时压缩就是解决该问题的一种良好技术手段。     

重型车辆湿式双离合器起步模糊控制研究

以重型车辆湿式双离合器(DCT)为研究对象,开展基于模糊控制的DCT起步控制研究.在考虑了油门踏板开度及其变化率、发动机运行状态、滑摩功等影响重型车辆起步品质因素的基础上,参考驾驶员的起步经验,制定了离合器起步的模糊控制规则.通过该车辆在某工况下的起步进行仿真计算,结果表明:综合考虑油门开度变化及变化率、发动机的转速变化和离合器主、被动端转速变化等因素的起步模糊控制策略可以用于重型车辆的起步控制.     

人体红外图像序列威胁行为理解

为识别人体的威胁行为,对提取的人体红外图像行为序列特征进行研究,提取每一帧图像的HOG特征并且并联形成序列二维特征。为降低特征维数,对二维图像进行离散余弦变换,使用变换后的包含该二维图像主要信息的前两列近似代替该图像的主要特征,最终使用最小二乘支持向量机对降维后的多段图像序列进行训练和测试,并给出最终训练测试结果。结果表明,该特征能实现对几种典型的威胁行为识别。     

Stability of the Third Generation Intensifier under Illumination

The stability under illumination of transmission-mode GaAs photocathode sealed in the third generation intensifier is investigated by use of spectral response testing instruments. The variations of spectral response with the illumination times under weak and intense illumination are compared. The variations of photoemission performance parameters are also characterized. The results show that during initial several weak illuminations photocathode behaves no evident decay and a maximum sensitivity is achieved, while under intense illumination the sensitivity of photocathode begin to decrease largely at the first illumination. The calculated performance parameters show that the variation of surface escape probability with illumination times is a direct cause of instability of photocathode. It is also found that under intense illumination peak wavelength is moved towards short-wave and peak response is decreased, which shows that the ability of long-wave response of photocathode is decreased.     

Passive Acoustic Radar for Detecting Supersonic Cruise Missile

A Passive Acoustic Radar is presented as a necessary complement to electromagnetic wave radar, which will be expected to be an effective means for detecting cruise missiles. Acoustic characteristics of supersonic flying projectiles with diverse shapes are expounded via experiment. It is pointed out that simulation experiment could be implemented using bullet or shell instead of cruise missile. Based on theoretical analysis and experiment, the ““acoustic fingerprint““ character of cruise missile is illustrated to identify it in a strong noise environment. After establishing a locating mathematical model, the technique of acoustic embattling is utilized to resolve a problem of confirming the time of early-warning, considering the fact that velocity of sound is much slower than that of light. Thereby, a whole system of passive acoustic radar for detecting supersonic cruise missile is formed.     

Super-resolution Restoration of Remote-sensing Images

A novel image restoration scheme, which is super-resolution image restoration algorithm Poisson-maximum-afterword-probability based on Markvo constraint （MPMAP） combined with evaluating image detail parameter D, has been proposed. The advantage of super-resolution algorithm MPMAP incorporated with parameter D lies in the fact that superresolution algorithm MPMAP model is discrete, which is in accordance with remote-sensing imaging model, and the algorithm MPMAP is proved applicable to linear and non-linear imaging models with a unique solution when noise is not severe. According to simulation experiments for practical images, super-resolution algorithm MPMAP can retain image details better than most of traditional restoration methods; at the same time, the proposed parameter D can help to identify real point spread function （PSF） value of degradation process. Processing result of practical remote-sensing images by MPMAP combined with parameter D are given, it illustrates that MPMAP restoration scheme combined PSF estimation has a better restoration result than that of Photoshop processing, based on the same original images. It is proved that the proposed scheme is helpful to offset the lack of resolution of the original remote-sensing images and has its extensive application foreground.     

Design and Simulation of TF and TA Controller for Missile

A nonlinear terrain following(TF) and terrain avoidance(TA) controller is proposed for missile control systems. Based on classical TF algorithm (adaptive angle method), a new method for TF controller is proposed by using angle of attack. A method of obtaining terrain outline data from digital elevation map (DEM) for TF control is discussed in order to save store space. A TA algorithm is proposed by using bank-to-turn technique. The block control model, which is suitable for backstepping design, is given for nonlinear model of missile. Making full use of the characteristics of the system and combining block control principle and backstepping technique, a robust controller design method is proposed. Uncertainties in every sub-block are allowed, and can be canceled by using the idea of nonlinear damping. It is proved that the state tracking errors are converged to a neighborhood of the origin exponentially. Finally, nonlinear six-degree-of-freedom simulation results for the missile model are presented to demonstrate the effectiveness of the proposed control law.