弹载图像小波实时处理技术研究

以战场图像侦察弹为需求背景，采用小波理论对弹载图像实时压缩技术进行了研究，分析了弹载图像压缩特点和机理，给出了小波帧内压缩算法模型及弹载实时压缩硬件实现电路，实验室硬件仿真结果表明该模型可用于战场弹载图像的无线传输。     

A digital technique to estimate second-order distortion usinghigher order coherence spectra

A digital spectral method for evaluating second-order distortion of a nonlinear system, which can be represented by Volterra kernels up to second order and which is subjected to a random noise input, is discussed. The importance of departures from the commonly assumed Gaussian excitation is investigated. The Hinich test is shown to be an appropriate test for orthogonality in the system identification. Tests for Gaussianity of two important sources, which are commonly used for Gaussian inputs in nonlinear system identification, are presented: (1) commercial software routines for simulation experiments, and (2) noise generators for practical experiments. The deleterious effects of assuming a Gaussian input when it is not are demonstrated. The random input method for evaluating the second-order distortion of a nonlinear system is compared with the sine-wave input method using both simulation and experimental data. The approach is applied to a loudspeaker in the low-frequency band     

Backward and forward linear prediction applied to ultraspectral image processing

Atmospheric infrared sounder images are ultraspectral data cubes that comprise over two thousand spectral bands accounting for well over 25 megapixels of information. In this paper, we focus on the analysis of backward and forward linear prediction (LP) applied in the context of ultraspectral image compression. We start by introducing a detailed analysis of the differences and similarities between them and proceed to present a mathematical model that integrates not only error signal but also LP coefficient encoding. In addition, to overcome some of the limitations of backward LP, we present a hybrid LP scheme where both, backward and forward LP, are put into consideration by dynamically interleaving them in order to minimize the mean square error of the error signal. The model is further extended to compare all three techniques, and both experimental and theoretical samples are contrasted to verify that hybrid LP provides most efficient compression method.     

A technique to estimate the relative gains, tuning phases, and RE phase shifts of the elements of a phased-array radar

An in-situ technique to estimate the following parameters of a phased-array antenna is described: 1) the relative array-element excitation voltages, 2) the array-element tuning phases, and 3) the RF phase shifts at the array elements. This technique has several significant features. First, it involves the use of two auxiliary antennas. One is a remote continuous wave (CW) source directed at the phased-array antenna. The other is a passive antenna mounted close to the phased-array antenna. Its output is used to produce a reference phase for phase measurements. Second, it contains a technique to reduce the errors in phase estimates. Third, it takes note that beam steering uses phase sums of the form (phi_{k} + beta_{kl}), wherephi_{k}is the tuning phase for thekth array elemenet andbeta_{kl}, is an RF phase shift of the array element, and pays special attention to reduce the errors associated with the estimates of these sums. Fourth, it assumes the use of a reasonably stable and strong CW source of commerically available quality. No other assumptions are made. Experimental results obtained with a 295-elementS-band space-fed phased-array antenna are given.     

The vertical resolution of ground-based microwave radiometersanalyzed through a multiresolution wavelet technique

The spatial resolution of a ground-based microwave radiometer is analyzed through a multiresolution wavelet transform. This technique allows us to compare the ability of the instrument to detect perturbations in a profile under different observing configurations and different noise levels. The use of a wavelet transform applied to performance indicators enables us to isolate the altitude and scale of the perturbation providing an unambiguous definition of resolution. A suitable ensemble of channels and view angles can then be selected to optimize the performance at different altitudes and different resolutions. Several angle/channel configurations are simulated. Among the configurations examined, a scanning system with only one channel offered a resolution comparable to a multichannel system for boundary layer sensing. The simulation suggests that increasing the bandwidth in the multichannel system improves the performance of the fixed view configuration. For investigation above 1 km, a multichannel system with fixed angle seems to offer a better performance at a coarser resolution     

基于图像准确处理的数字图像处理系统结构设计及其功能实现

为了满足图像精确处理需求,利用现场可编程门列阵动态配置灵活性,采用高性能Cysclone系统芯片作为核心处理器,并配合1394总线链路层构建图像处理系统,实现图像数据采集和处理。系统方设计分为图像采集、存储、处理和传输等模块,先通过摄像头采集QR码图像,进行滤波等预处理工作,然后经定位、提取信息、检索纠错等得到字符信心。该系统采用图像处理技术,很好地解决了不同光照条件引起的识别不确定性,精确区分前景和背景,减少信息遗漏,设计硬件结构,提高系统速度和面积技能,优化系统硬件操作。在软件设计中,采用软核处理器,完整图像信息的提取。系统设计与传统二值化、滤波等检测方法相比,处理时间大大缩短,同时处理图像分辨率也得到提高。     

数字图像处理与识别系统的开发研究

信息技术的快速发展为各行业领域注入新鲜的活力.以当前数字图像处理技术、识别技术等为例,其本身以计算机技术为依托,能够完成信息传输、处理、存储等工作,应用范围极广.然而从现行计算机感知能力角度看,仍需将相关的理论与实践经验作为指导,如人脸识别、纸币识别等,要求做好图像处理与识别系统设计.本文将从数字图像处理、图像识别方法在人脸图像识别中的应用以及图像识别系统在识别残损纸币中的应用角度,对系统开发思路进行探析.     

生物芯片扫描仪图像处理过程及方法

介绍了生物芯片经扫描后所得到图像的处理过程及方法,并简要介绍了图像采集、数据提取及数据分析的相关问题。通过对这些方法、问题的探讨,使读者能对生物芯片扫描仪中的图像处理过程及方法有一个初步的了解和认识。     

阵列处理技术在超短波侦收中的应用

目前超短波宽带自适应天线阵列侦收技术成为一种很有前途的抗多径、抗干扰的 空域技术。采用自适应数字波束处理技术,侦收超短波频段内需要截获的全部通信信号,并能 够分别形成波束加以接收,抑制其他同频信号对该信号的干扰,提高超短波频段信号的侦收和 获取能力。     

小波变换域数字图像增强算法及实现

图像增强是数字图像预处理中的重要方法,其主要目的是改善视觉效果.小波变换在图像压缩和图像分割两个方面应用较为广泛,图像增强方面应用较少.现概括了图像增强的原理,阐述了图像增强的方法,分析了一种小波变换域的图像增强算法并在Matlab环境下仿真实现.该算法首先使用haar小波对图像进行2层分解,然后对低频部分进行增强,对高频部分进行衰减,实验结果证明这是对图像去噪和增强的一种有效方法.     

基于图像处理的印章书写时序研究

印章书写时序鉴别是现有司法鉴定过程中的一个技术难题,文中研究针对此问题,通过对多个样本的处理分析,得到一种可技术辨别的图像特征,并根据各图像特征体现出的差异,提出了基于方差和基于交叉区域提取的技术鉴别算法,实现了印字样本的区分,具有较高的识别率。最后,基于上述两种算法,针对不同测试结果进行了综合对比及结果分析。     

红外图像序列处理的锁相热成像理论与试验

红外锁相热成像技术是一种基于热波信号处理的主动式红外热成像技术,特别适用于复合材料及复杂结构构件的无损检测.阐述了红外锁相热成像技术的原理,采用有限元方法对正弦规律变化的热流在构件中的传递过程进行了分析.利用正弦规律调制光源作为热激励源对不同材料的试件加载,通过Jade MWIR 550焦平面红外热像仪进行图像序列的采集,深入研究了图像序列数字滤波算法,并采用Savitzky-Golay数字平滑滤波算法消除了高频噪声的影响,在此基础上,利用FFr算法得到了热波信号的幅值与相位图像,并采用Visual C++平台开发了基于图像序列处理的红外锁相软件检测系统.试验结果表明,通过选取适当的激励加载频率可准确获得缺陷特征.     

A dynamic range extension scheme applied to a TDI CMOS image sensor

A dynamic range extension scheme applied to a time delay integration （TDI） CMOS image sensor （CIS） is presented. Two types of pixels with higher and lower conversion gain are adopted in the pixel array, which are suitable for capturing images in low and high illumination respectively. By fusing the two kinds of pixels＇ output signals in the process of TDI accumulation, a high dynamic range image can be achieved. Compared with the traditional multiple integration technique, no photoelectrons generated during the exposure time are discarded by the reset operation, and thus a higher level of signal-to-noise ratio （SNR） can be retained. A prototype chip with an 8 × 8 pixel array is implemented in a 0.18 μm CIS process, and the pixel size is 15 × 15 μm2. Test results show that a 76 dB dynamic range can be achieved in 8-stage TDI mode, when the SNR boost can reach 7.26 dB at 90.8 lux.     

多线程在数字图像实时接收处理中的应用

阐述了基于Windows95/98平台的多线程应用程序设计与实现,给出了一个多线程技术在基于PC的数字图像实时接收处理系统中的应用实例。     

数码相机防抖技术及检测方法进展

本文通过对相关国内外专利及文献的检索,综述了近年来数码相机防抖技术的进展,包括机械防抖和数字防抖技术;同时报道了防抖性能检测技术的最新动态,提出防抖技术及检测方法领域的发展趋势.     

基于图像处理的数字仪表字符自动识别研究

为提高数字仪表图像识别率, 结合机器视觉技术, 在图像预处理的基础上, 提出一种PSO的LSSVM参数优化方案.在图像预处理阶段, 采用Hough变换校正, 并通过形态学处理和二值化, 以提高图像采集的效率; 然后采用连通域的方式实现对图像区域的定位分割, 并通过七段码实现图像特征提取; 针对数字仪表识别是多分类的问题...     

A window-based image processing technique for quantitative andqualitative analysis of road traffic parameters

Traffic information is an important tool in the planning, maintenance, and control of any modern transport system. Of special interest to traffic engineers are parameters of traffic flow such as volume, speed, type of vehicle, queue parameters, traffic movements at junctions, etc. Various algorithms, mainly based on background differencing techniques, have been applied for this purpose. Since background-based algorithms are very sensitive to ambient lighting conditions, they have not yielded the expectative results. In this paper, we describe a novel approach to measure traffic parameters. This approach is based on applying edge-detection techniques to the key regions or windows. This method of measuring road traffic parameters eliminates the need of a background frame, which is an essential, but unreliable technique for background-based image-detection methods. A dynamic threshold selection technique has also been introduced to select the threshold value automatically. The image process algorithm has been applied to measure basic traffic parameters such a traffic volume, types of vehicles, as well as the complex traffic parameters such as queue parameters and movements of vehicles at a traffic junction     

计算机图像处理技术在激光－荧光法肺癌定位中的应用

介绍了激光－荧光法早期肺癌诊断和定位技术，并提出一种与计算机图像处理技术结合的新方法。其结果将改善诊断和定位的准确率，有效地克服当前激光诱导荧光早期肺癌诊断可能出现的假阳性问题。