浅论在刑事案件细微特征检验照相中传统胶片的成像质量优于数码CCD、CMOS成像质量

由于数码相机性能的迅速提高和价格的不断降低，以及其突出的优点，目前在一般照相方面，已经大量推广，取代传统的照相胶片，但是在刑事照相方面，尤其是在拍摄细微痕迹时，还是不如传统照相胶片。传统照相胶片，尤其是反转片和黑白胶片在刑事照相时，能获得更高的感光度、解像力和清晰度，能为影像提供更丰富的细部层次和更真实的色调，对揭示刑事案件现场的微细痕迹效果更好。     

家庭数码影像完美解决方案

目前流行用数码相机和喷墨打印机搭配以制作数码照片,但是有些摄影爱好者,已经拥有质量很好的传统照相机,可以不购置数码相机也能够建立数码影像制作系统。为此,本文推荐一套家庭数码影像系统：爱普生Perfection2400photo扫描仪＋Stylus Photo打印机,实际应用效果很好,经济而实惠。     

基于多波束系统的水下目标近程回波亮点声图像

模拟多波束系统,仿真得到了水下目标的二维回波亮点声图像。先采用小分置角双基地目标回波特性计算的近场板块元方法,计算得到水下目标的传递函数。再根据多波束系统的理论,建立了水下目标回波亮点二维声图像的基本框架,实现了水下目标回波亮点二维声图像仿真。最后得到了水下目标不同方位角情况下近程二维回波亮点的声图像。     

Large aperture static interferential multispectral image compression with motion compensation and region of interest coding

To perform better on interferential multispectral image compression, wavelet transform based on motion compensation and region of interest coding and asymmetric zerotree was proposed. According to the movement in the images and the characters of spectrum, the motion compensation and raising coefficients of intensive interference area were used in this wavelet. In this way, the relativity among the spectra is reduced and the intensive interference area coefficients can be coded preferentially. The asymmetric zerotree was proposed due to the unsymmetrical structure of images formed by the wavelet. Experimental results show that with eightfold compression, this algorithm outperforms the three-dimensional set partitioning in hierarchical trees (3DSPIHT) in the range of 0.35–0.49 dB in power signal-to-noise ratio (PSNR) and outperforms the 2DSPIHT in the range of 2.24–2.62 dB in PSNR. Compared to joint picture expert group 2000 (JPEG2000) upscaling method, the effect of intensive interference area is also improved 0.29–0.38 dB in PSNR. Meanwhile, the average of mean square error of spectra within 46 spectrum bands is reduced to 9.69. Translated from Journal of Xi’an Jiaotong University, 2006, 40(4):449–453 [译自: 西安交通大学学报]     

一种2/4线话音接口的设计与实现

文章介绍了一种2/4线话音接口和回波抵消器的设计与实现方案,该方案实现了2/4线的话音接口,包括A/D、D/A变换,ADPCM编解码,自适应回波抵消等。其中,ADPCM编解码和回波抵消器是基于FPGA使用VHDL语言编写实现的。测试表明,该接口电路以较小的资源消耗,提供了优异的话音通信质量,在电力系统话音通信中具有重要的实用价值。     

星载SAR对舰船高分辨成像研究

研究了星载SAR对舰船高分辨成像的难度和方法。在星载SAR舰船数据获取模型的基础上，着重分析了舰船航行以及船体在特定海情时三维转动对星载SAR成像的影响，研究了星载SAR舰船数据的ISAR成像方法，并给出成像算法流程，仿真结果验证了该方法的有效性。     

一种快速回声消除算法及DSP实现

在回声消除系统中,人们希望回声消除器不仅要收敛速度快而且要鲁棒性好。PNLMS和PNLMS 算法具有收敛速度快的优势,然而在双端发声情况下,它们就会产生大的失调,甚至不能保证滤波器收敛。为了克服上述问题,根据正交原理,我们提出了OP-PNLMS算法,该算法不仅具有PNLMS和PNLMS 算法的快速收敛性能,而且受双端发声和嘈杂背景噪声影响极小。即使是在单端发声时,该算法的性能也优于NLMS以及PNLMS和PNLMS 算法。此外,讨论了该算法在定点DSP上的实现方案。     

A hybrid PET‐MRI: An integrated molecular‐genetic imaging system with HRRT‐PET and 7.0‐T MRI

A PET‐MRI fusion system is developed for molecular‐genetic imaging. The purpose of the system is to obtain images of the in‐vivo human brain using two high‐end imaging devices, an advanced PET and an ultrahigh‐field MRI. These are the HRRT‐PET, a high‐resolution research tomograph dedicated to brain imaging on the molecular level, and the 7.0‐T MRI, an ultrahigh field version used for morphological imaging. HRRT‐PET delivers high‐resolution molecular imaging with a resolution down to 2.5 mm FWHM, which is currently the highest spatial resolution available for the observation of the human brain's molecular activities, including enzymes and receptors, which are manipulated genetically, such as reporter genes and probes. The 7.0‐T MRI began to reveal submillimeter resolution images of the cortical as well as deep brain areas, down to 250 μm, which allows us to visualize the fine details of the cortical and brainstem areas, including the line of Gennari in the visual cortex and the corticospinal tracts in the pontine area. The current PET‐MRI fusion imaging system produces the highest quality images of molecular and genetic activities of the human brain in vivo. It is starting to provide many answers to the key questions about the neurological diseases. Some of these start providing answers to many cognitive neuroscience problems with clear molecular and genetic bases. There is great potential in the PET‐MRI for early diagnosis of cancers as well as other neurological diseases, which we were previously unable to diagnose, such as microscopic molecular changes that occur in Parkinson's and Alzheimer's diseases. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 252–265, 2007     

超高速运动目标回波及其对雷达检测的影响

超高速运动目标是现代雷达目标检测中遇到的新情况。文中建立了超高速运动目标的回波模型，得出其信号模型是一多项式调频信号。根据超高速运动目标回波信号的特点，给出了先进行多普勒处理再进行脉冲压缩的超高速运动目标检测方法。分析了目标的超高速运动对雷达目标检测的影响，并对理论分析进行了仿真验证。最后给出了问题的解决方向。