星上多通道遥感图像的实时合成压缩

针对星上图像整合电路工作频率过高而造成的成像系统工作不稳定的问题,讨论了相机结构的改进,提出了一种基于现场可编程门阵列（FPGA）平台实现星上时间延迟积分CCD（TDICCD）遥感图像实时合成压缩的方法。介绍了星上多通道遥感图像实时合成压缩的原理。针对TDICCD线阵推扫成像模式的特点,使用改进的JPEG-LS压缩算法;通过自适应量化动态地控制码率,在FPGA硬件平台上实现了图像数据的实时合成压缩。试验验证结果表明,在无损压缩和2倍压缩时,系统主时钟从原来的100 MHz分别降低为80 MHz和64 MHz,整合电路的工作稳定,恢复图像的峰值信噪比（PSNR）满足大于80 dB的要求。提出算法的存储量小,处理每行的平均时间为57.5 μs,小于相机的最小行周期63 μs,满足实时性要求。本文系统可靠性高,算法稳定,实现了星上多通道时间延迟积分CCD相机内部的实时合成压缩。     

基于双DSP的遥感图像实时并行处理系统

在简要介绍遥感图像实时处理系统发展历程的基础上,详细分析几种基本的并行处理策略、并行处理技术及其相关的并行处理硬件平台,并针对具体应用背景提出了基于双DSP的遥感图像实时并行处理系统方案,同时,给出了利用上述并行处理系统实时处理展宽卫星云图的最终结果.该项并行处理方案的提出为将来星载大数据量实时处理技术的实现做了有益的尝试.     

一种高分辨力遥感图像星上压缩方案

DWT是近年来发展起来的数据变换方式,它对整幅图像进行相关计算,比DCT更适合图像压缩.DSP芯片的飞速发展为实时图像处理提供了有利条件.DWT变换编码和高档DSP芯片相结合,可以认为是目前最理想的星上压缩方案之一.在此分析了DWT+DSP方案应用于高分辨力遥感图像星上压缩的优势和可行性,并提出了初步构想.     

高空间分辨率和高光谱遥感图像融合技术

高光谱技术的发展与应用对高维的高光谱遥感数据的处理方法提出了更高的要求,其中高光谱融合技术是热门并具有相当难度的研究领域.高光谱图像数据与高空间全色波段数据进行融合处理,可以在大大改善融合后成象光谱图像空间解析特性的条件下,选择性保持满足应用需求的成象光谱图像的光谱物理特性和波形形态,为深入地研究提供更好的条件.本文介绍了高光谱与高空间影像融合一些典型算法,着重研究了基于最佳指数准则的高光谱图像融合方法,并给出了上海地区PHI高光谱数据和高分辨率全色航空像片融合实例,展现了该技术良好的应用潜力.     

提高图像空间分辨率方法研究

在航空/航天遥感应用方面,利用同一地域遥感图像的信息互补特性来提高空间分辨率的方法是国内外学者探索的热点,本文采用信息累积的代数插值方法来提高图像的空间分辨率,取得了明显的效果.     

基于图像融合提高图像空间分辨率技术研究

在航空/航天遥感应用方面,利用同一地域遥感图像的信息互补特性来提高空间分辨率的方法是国内外学者探索的热点,本文采用频率域解混频的方法来提高图像的空间分辨率,取得了明显的效果.     

最小化预测残差的图像序列压缩感知

提出了一种最小化预测残差的图像序列压缩感知算法以实现高速相机输出图像的实时压缩.首先,在编码端仅使用映射矩阵对原始输出图像进行压缩,将压缩得到的观测向量通过信道传输到解码端.接着,在解码端对相邻帧进行运动估计和运动补偿,得到一幅待重建图像的预测图像,利用压缩感知算法对原始图像和预测图像之间存在的预测残差图像进行重建.最后,用迭代的方法优化预测残差图像的重建结果,直到连续两次的重建结果之差小于设定阈值,从而获得重建的原始图像.采用DALSA公司的CR-GEN0 H6400相机进行的实验表明,该算法可以实现1 000 frame/s图像的实时压缩,并且图像重建质量比独立地重建每张图像至少提高了2～6 dB,有效地实现了对高速相机输出图像的实时压缩与高质量重建.     

高空间冗余图像DCT压缩产生的几何衰变

离散余弦变换(DCT)压缩图像的客观质量评价通常采用均方误差(MSE)和峰值信噪比(PSNR),而缺乏对图像几何衰变的考虑,这正是基于位置信息的图像测量系统的关键.针对这一问题,对两幅高空间冗余图像进行DCT压缩实验研究,结果表明:用4×4分块,1:2压缩比时,MSE和PSNR变化不大,但有1或2个像元的几何衰变.与一般情况下光学测量系统总体误差只有1～2个像元比较,在因压缩而产生像元级的位置变化时,将会严重影响测量精度,因此对这类图像进行DCT压缩时应十分关注几何衰变.     

航空视频图像的实时压缩算法

提出一种航空视频图像快速编码方案,在工控计算机上实现两路PAL制式彩色视频的同时实时压缩存储。方案选择离散余弦变换（DCT）来对图像去相关性,在比较各种DCT方法后,选择AAN算法进行优化改进,并给出优化的依据。方案同时优化了可变长编码(VLC)中VLC表的检索方式。通过对视频压缩算法中运算量最大的这两个算法模块的优化改进,在P4 3.0G处理器上实现8ms内压缩一帧768x576彩色图像。算法在32:1的压缩比下,PSNR值为30.18,接近小波压缩算法在该压缩比下的PSNR值,同时保证压缩质量。实验结果表明编码方案在压缩速度、压缩率与压缩质量三者间取得平衡,能很好的满足航空视频图像实时压缩的应用。     

粒子群优化结构测量矩阵的遥感压缩成像

针对块循环测量矩阵应用于遥感压缩成像存在图像重构性能不理想的问题,本文把粒子群智能优化算法引入到块循环矩阵优化中,实现了在保持矩阵结构不变的同时对块循环矩阵的优化。首先以相关系数的Welch界为阈值约束Gram矩阵非对角元素构造目标矩阵;然后以Gram矩阵逼近目标矩阵的方式建立目标函数,将优化对象改为构造块循环矩阵的自由元向量。为提高优化效率,文中采用权重自适应更新的方式提高粒子搜索能力。开展了相关重构对比实验,结果表明,优化后的块循环测量矩阵在保持矩阵结构的同时,降低了与稀疏变换矩阵的相关性,其与稀疏变换矩阵的最大相关系数、平均相关系数和阈值平均相关系数分别降低了0.027 3、0.017 5和0.004 6,得到的结果显示优化的块循环矩阵提高了图像的重构性能。     

Infrared scanning microscope with high spatial resolution

Technical parameters and possible applications of an infrared scanning microscope with a spatial resolution of up to 3 μm are considered. It is shown that the device works with both array and linear photodetectors. Original PC software was designed to control the scanning process interactively and receive and process images of objects in the infrared range,.     

一种高分辨率数据采集系统的设计

针对石油测井采集信号的特点,设计了一种高分辨率24位数据采集系统。给出了单片机和A/D转换器的接口电路,设计上位机控制软件。该采集系统采样最大频率为32ksps,可超前采集1s,采集数据以二进制文件形式保存。     

高空间分辨率分布式光纤测温系统的设计及应用

分布式光纤测温系统是一种新型的线型感温探测器,以光纤作为传感器,可实现沿光纤分布的温度实时测量。理论分析了分布式光纤测温系统的原理以及影响空间分辨率指标的因素,并给出了0.5m高空间分辨率分布式光纤测温系统的设计以及测试情况。将高空间分辨率分布式光纤测温系统应用于电缆温度测量,测量结果表明0.5m空间分辨率下对小区域电缆过热点的探测更为显著,可及时发现潜在的火灾隐患。     

Energy-filtering TEM at high magnification: spatial resolution and detection limits

Energy-filtering TEM (EFTEM) has turned out to be a very efficient and rapid tool for the chemical characterization of a specimen on a nanometer and even subnanometer length scale. Especially, the detection and measurement of very thin layers has become a great application of this technique in many materials science fields, e.g. semiconductors and hard disk technology. There, the reliability of compositional profiles is an important issue. However, the experimentally obtainable spatial resolution strongly influences the appearance of a thin layer in an EFTEM image, when dimensions reach subnanometer levels, which mainly leads to a broadening of the layer in the image. This fact has to be taken into account, when measuring the thickness of such a thin layer. Additionally, the convolution decreases contrast which makes the layer less visible in the image and finally determines the detection limit.In this work we present a systematic study on specifically designed Mn/PdMn multilayer test specimens to explore the practical aspects of spatial resolution and detection limits in EFTEM. Although specific to the ionization edges used, we will present general conclusions about the practical limitations in terms of EFTEM spatial resolution. Additionally, work will be shown about low energy-loss imaging of thin oxide layers, where delocalization is the main factor responsible for broadening.     

An automatic pulsed laser microfluorometer with high spatial and temporal resolution

The paper describes an automatic pulsed laser microfluorometer with high spatial and temporal resolution, developed in our laboratories. The instrument consists of: (i) a nitrogen-laser-pumped dye-laser for the excitation of the fluorescence, (ii) a microscope with additional optics to focus the excitation beam on the sample and to collect the fluorescence, (iii) filters or monochromators to select the output wavelength, (iv) a fast photomultiplier tube to detect the signal, and (v) a dual time-scale microprocessor-controlled signal averager for the acquisition and processing of the signal. Examples are given that show the potential of the time-resolved fluorescence microscopy in studying, quantitatively and qualitatively, the properties of fluorescent molecules.     

A digital system for producing X-ray images with a high spatial resolution

A system for detecting X-ray shadowgraphs with a high spatial resolution, in which a shadowgraph formed on a luminophor is transferred to a charge-coupled device (CCD) matrix by using an objective lens, is considered. The signal stored on the CCD matrix is read, converted, and transmitted to the computer for further processing and representation. A 25-lp/mm spatial resolution was obtained for a 10.8 × 10.8-mm input field of the system. The measurements were performed by using a tungsten-wire standard placed on the surface of the input field of the detecting system, when the anode voltage was 45 kV, the anode current was ～2 mA, and the focal distance was 450 mm. It was shown that the 25-lp/mm spatial resolution is not limiting and that it is possible to attain a value of 40 lp/mm or higher.     

Practical considerations for high spatial and temporal resolution dynamic transmission electron microscopy

Although recent years have seen significant advances in the spatial resolution possible in the transmission electron microscope (TEM), the temporal resolution of most microscopes is limited to video rate at best. This lack of temporal resolution means that our understanding of dynamic processes in materials is extremely limited. High temporal resolution in the TEM can be achieved, however, by replacing the normal thermionic or field emission source with a photoemission source. In this case the temporal resolution is limited only by the ability to create a short pulse of photoexcited electrons in the source, and this can be as short as a few femtoseconds. The operation of the photo-emission source and the control of the subsequent pulse of electrons (containing as many as 5 x 10(7) electrons) create significant challenges for a standard microscope column that is designed to operate with a single electron in the column at any one time. In this paper, the generation and control of electron pulses in the TEM to obtain a temporal resolution <10(-6)s will be described and the effect of the pulse duration and current density on the spatial resolution of the instrument will be examined. The potential of these levels of temporal and spatial resolution for the study of dynamic materials processes will also be discussed.     

RS422串行通信在转台实时控制中的应用

阐述了利用CPLD实现串并转换的设计方案和具体实现方法，并将其应用于转台实时控制中，取得了理想的控制效果。实验证明此方法可靠性高，灵活性好，易于扩展，具有一定的应用价值。     

Development of custom-made RF coil for magnetic resonance velocimeter with a high spatial resolution

Magnetic resonance velocimetry (MRV) is a versatile flow visualization technique that is used to measure three-component velocity vectors in a 3D space. However, the spatial resolution of MRV is relatively poor in comparison with optical flow visualization techniques, thereby limiting its applicability to small-scale flows and wall shear stress (WSS) estimation. Thus, we built a solenoid RF coil and evaluated its performance in terms of spatial resolution improvement by measuring the laminar flow in a circular tubing. The coil was developed for a 4.7 Tesla MRI system and for tightly wrapping a flow tubing with an inner diameter of 2 mm. The custom-made RF coil could precisely capture the velocity vectors in a voxel that was 11 times smaller than a commercial coil at the same SNR. Therefore, the WSS errors estimated using the custom-made and commercial coils were 8.5 % and 42.3 %, respectively.