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。     

基于FPGA的偏振OCT双路信号处理系统

针对目前基于计算机的偏振OCT具有系统数据处理速度慢、不能实时显示等问题,设计了基于FPGA的偏振OCT双路信号处理系统.FPGA设计包含同步时序控制、正交解调和CORDIC运算三个模块.同步时序控制模块为系统的各器件提供同步控制信号,实现数据的实时处理和同步显示.正交解调和CORDIC运算模块对预处理后的干涉信号进行振幅解调和相位解调,获取反射率和双折射率数据,经USB接口送入计算机进行实时显示.对玻片、云母片和生物组织进行偏振OCT系统成像,对成像结果的分析验证了系统具有实时探测生物组织反射率和双折射率的能力.     

基于Storm流处理的数控机床运行数据监测方法的设计与实现

针对目前数控机床运行数据种类多、数量大且难以实现实时处理的问题，提出一种基于Storm流处理技术的数控机床运行数据监测方法。该方法采用实时大数据计算框架Storm作为核心，通过外置传感器和数控系统通信协议获取数控机床运行数据。使用Kafka作为消息队列将机床运行数据上传给Storm，然后在Storm框架中进行数据统计、数据异常检测等实时分析业务，之后将分析结果存储于数据库中，并实现分析结果的可视化展示。在实际生产环境中对基于Storm流处理的监测方法进行测试，实验结果表明：该方法能够实现对数控机床运行数据的实时监测与处理，具有强实时计算能力、高扩展性的优点;并且在处理相对复杂的数控机床运行数据监测业务时，该方法的优势更显著。研究结果为数控机床运行数据监测提供了新思路，该监测方法具有广阔的工程应用前景。     

基于ADSP—TS201的实时成像处理器

本文介绍基于ADSP—TS201信号处理板实现的实时成像处理系统。对使用不同硬件资源情况下的成像性能进行了分析。     

自适应Chirplet信号分解用于ISAR目标三维转动检测

当ISAR目标作复杂的三维转动时,目标上各散射点的相位误差将与它们在目标上所处的位置有关,传统的相位聚焦方法难以采用统一的相位校正函数来进行补偿。为解决此问题,论文提出了一种基于自适应Chirplet信号分解的ISAR目标三维转动检测方法,该方法使用自适应Chirplet信号分解的快速算法来估计散射点子回波的相位信息,并根据两个散射点相位之间的非线性度来判断目标是否存在三维转动,从而只选择那些仅具有二维转动的数据段进行成像。仿真实验结果表明了它的有效性。     

一种通过相续雷达成像构建目标三维像的算法

逆合成孔径雷达(ISAR)作为成像雷达技术之一,它是应用雷达波束对基于遥感目标的二维像进行观测.ISAR对相继像的观察就类似于采用摄像机捕捉移动的画面.在光学成像的领域里,将图像而成的二维速度变换称为"光速流"或者是"速度场".当摄像机与目标之间的相对运动是已知的时候,那么基于速度场的以相继运动图像来估计目标的三维形态是合理的.     

三维超声地震模型实时成像系统

室内水槽实验是研究地质沉积过程及其演化规律的重要手段,高精度获取沉积过程中的地质体的变化是这类模拟实验非常关键的环节。文章介绍了新研制的三维超声地震模型实时成像系统的主要组成及关键技术。该系统用于模拟海上地震,可以在沉积实验后通过快速测量及对数据的实时偏移处理与成像可以获取变化的多层复杂地质模型动态图像,极大地提高了实验效率和成像精度。该系统具有良好的实时性、成像质量以及探测范围,在对研究地质沉积、海洋地质以及三维地震模型研究等方面有着广泛应用前景。     

利用FPGA实现红外焦平面阵列实时非均匀性校正

实时非均匀性校正是红外成像的一项关键技术。根据红外焦平面阵列探测元光谱响应的特点和基于参照源的两点温标非均匀性校正理论，提出一种利用FPGA硬件实现红外焦平面阵列实时非均匀性两点校正的新方法。该方法动态范围大、处理速度快，适用于红外成像系统实时图像处理场合。仿真和实验结果证明是可行的。     

工业非胶片射线照相技术 二．数字射线成像

数字射线成像不同于射线实时成像，存数字射线成像系统巾，由各种各样传感器捕获的射线影像信息以电子数据的形式存储存特定的存储器巾，以便进一步处理或存档。本文阐述数字射线成像的一些基本观念、技术、成像系统，以及采用的相关传感器如：1．涂布在非品硅薄膜晶体管上的荧光体：2．涂布在薄膜晶体管上的非晶硒光电导体；3．涂布在电荷耦合器或互补金属氧化物上的荧光体；4．可进行光激励的存储荧光体；5．涂布在线阵列器上的荧光体：6．扫描电子束法等．     

基于双CPU结构的数据监控系统设计

针对通信系统中，对所有客户线路的电压、电流、温度等数据进行实时多路采集监控，提出了一种基于双CPU结构的数据监控系统的设计方法以及硬件组成。讨论了系统主要芯片之间的连线方法以及软件流程。该系统已经成功应用在邮电系统48V通信线路监控。实践证明，双CPU设计方案不仅满足了系统高运算量、高实时性、抗干扰性要求，而且优化了软硬件设计。     

柴油机加速振动信号的阶比双谱特征提取

针对发动机加速过程振动信号的非平稳性和混有大量噪声的特点,提出计算阶比跟踪和双谱相结合的方法,将振动信号按等角度间隔进行软件重采样,得到阶域内的平稳信号,再进行双谱分析,通过仿真信号验证了该方法优于传统双谱。为了充分利用阶比双谱图中的信息,提出双谱特征阶比面的概念,通过比较阶比平面内的累加能量来反映不同工况的变化。诊断实例表明,该方法能有效提取柴油机曲轴轴承的故障特征。     

Inverse synthetic aperture radar imaging of ship target with complex motion

High-resolution inverse synthetic aperture radar (ISAR) imaging and recognition of ship target is very important for many applications. Although the principle of ISAR imaging of ship target on the sea is the same as that of flying target in the sky, the former usually has more complex motion (fluctuation with the oceanic waves) than the latter, which makes the motion compensation very difficult. However, the change in phase chirp rate caused by the complex motion of ships will deteriorate the azimuth focusing quality. In this paper, we first model the complex motion of ship target with cubic phase terms (parameterised on chirp rate and its change rate), then a new ISAR imaging method, referred to as TC-DechirpClean, is proposed, which estimates the chirp rate and the change rate of chirp rate of all scatters in the time? chirp distribution plane. Both numerical and experimental results are provided to demonstrate the performance of the proposed method.     

两种超分辨ISAR成象算法

为提高逆合成孔雷达（ＩＳＡＲ）图象的分辨率,本文介绍了连续Ｈｏｐｆｉｅｌｄ神经网络和ＥＳＰＲＩＴ两种超分辨技术。通过对实验ＩＳＡＲ回波数据的处理表明,与常规的ＦＦＴ算法以及普通超分辨成象算法相比较,这两种新算法明显地提高了图象分辨率。     

自谱与双谱相互转换的一种实现方法

阐述自谱与双谱相互转换的一种实现方法.该方法通过对自谱添加线性相位,根据双谱的数值估计算法计算获得双谱在三维空间的幅频图,通过推导双谱与自谱估计算法之间的等价关系以及所得的幅频图来实现两者之间的相互转换.文末给出了一数值算例,验证该方法的可行性与有效性.     

用ISAR横向动态一维像分辨编队飞机架数

提出了ＩＳＡＲ横向动态一维像的概念并研究将其用于分辨飞机编队架数。分别研究了近似刚性、非刚性多目标架数分辨方法,给出了两架飞机编队外场回波数据横向动态一维像。用一维像分辨目标架数的方法可用于窄带相参雷达。最后,给出了编队飞机多目标架数分辨方案。     

New ISAR imaging algorithm based on modified Wigner?Ville distribution

Inverse synthetic aperture radar (ISAR) imaging of air, space or ship targets with complex motion has attracted the attention of many researchers in the past decade. Complex motion of targets induce cross-range scatterer-variant quadratic phase terms, which will degrade the cross-range resolution and affect focusing quality. A new algorithm is proposed for the ISAR imaging of complex moving targets. First, conventional range alignment, phase compensation and range compression are performed over the raw phase history data such that each range bin can be modelled as the sum of several linear frequency modulation or chirp signals. Secondly, a modified- Wigner?Ville distribution (referred to as M-WVD) approach is proposed, which is based on a scale transform in the time-frequency distribution plane and can effectively suppress the troublesome cross-term interference associated with WVD via coherent integration. Finally, the azimuth ISAR image can be obtained via a simple maximisation projection from the two-dimensional accumulated plot to the azimuth dimension. Compared with existing WVDbased ISAR imaging algorithms, the proposed method has the following features: better cross-term interference reduction achieved at no resolution loss, computationally more efficient with no expensive two-dimensional parameter search, and higher signal processing gain because of coherent integration during the whole imaging time. Bothnumerical and experimental results are provided to demonstrate the performance of the proposed method.     

ISAR motion compensation using the burst derivative measure as a focal quality indicator

Inverse synthetic aperture radar (ISAR) is an imaging technique that shows great promise in classifying airborne targets in real-time under all weather conditions. The success of classifying targets using ISAR is predicated upon forming highly focused radar images of these target. Efforts to develop highly focused radar imaging computer software have been challenging, mainly because the imaging depends on and is affected by the motion of the target. Computationally intensive motion compensation algorithms have been developed to remove the unwanted degrading effects of target motion. Those particular motion compensation algorithms which require the use of a space domain focal quality indicator (e.g., entropy) to determine image sharpness as processing proceeds pay a severe computational penalty due to the large number of two-dimensional fast Fourier transforms (2D-FFTs) which must be computed. This is due to the fact that the actual processing of ISAR data is done primarily in the spatial frequency domain and not in the space domain where the final ISAR image is displayed. If a focal quality indicator could be developed to measure image sharpness in the spatial frequency domain, then the computational burden introduced by the numerous 2D-FFTs could be greatly relaxed. This article describes the use of a new focal quality indicator called the burst derivative measure for determining ISAR image sharpness in the spatial frequency domain. Tests have been performed on simulated as well as actual ISAR data using both the burst derivative measure and the entropy measure. Results indicate that the burst derivative measure, when used in conjunction with the entropy measure, can greatly reduce the number of 2D-FFTS presently required in these motion compensation algorithms.©1993 John Wiley & Sons Inc     

ISAR imaging of manoeuvring targets with the range instantaneous chirp rate technique

The conventional range instantaneous Doppler (RID) algorithm is a well accepted inverse synthetic aperture radar (ISAR) imaging method for manoeuvring targets. In the RID imaging, the cross-range resolution depends on the instantaneous Doppler of scatterers at the imaging instant. For a high manoeuvring target, the instantaneous Doppler of scatterers may be small at some imaging instants and the satisfactory RID images may not be obtained. On the other hand, a large instantaneous chirp rate is often present for the same scatterer at the same instant for RID imaging. In order to obtain some additional information of a manoeuvring target, a novel ISAR imaging approach, referred to as the range instantaneous chirp (RIC), is proposed based on instantaneous chirp rate of scatterer to provide cross-range resolution. Using the proposed imaging algorithm, with the same received data of RID, a RIC image is generated at the same instant with a different `view`. Therefore the RIC image may provide some additional information that is not shown in the RID image. With both the RIC and RID images, a better target recognition and identification can be achieved for high-manoeuvring targets. The proposed RIC algorithm is verified by raw radar data.