CBERS-02B影像HR数据的地形效应校正实现

中巴资源卫星CBERS-02B星是我国第一颗能为众多行业提供高分辨率图像数据的卫星,广泛应用于国土资源、农业、林业、水利、环保、灾害监测、测绘、城市规划等众多领域。考虑到山区地形对高分辨影像的山区地表特征反演精度的影响,对数字高程模型(DEM)精度对地形校正的影响进行了初步分析,比较了几种常用地形校正模型：C校正、SCS+C校正、Minnaert校正和Ekstrand-r校正,并对校正结果进行了评价,结果表明以往的地形校正方法对CBERS-02B影像HR数据具有一定可行性,从而为中巴资源卫星CBERS-02B影像的地形校正提供了依据。     

CBERS-04星PAN/MUX图像几何定位精度评价

CBERS-04星的成功发射,为国土资源、农业和林业等诸多领域提供服务支持。图像定位精度是衡量遥感影像应用价值的重要指标,从业务应用角度出发,通过对CBERS-04星全色/多光谱载荷获取的图像进行无控制点的RPC处理后,结合野外实测的42个控制点和利用实测控制点生产的Worldview-2正射影像为基础底图,比较控制点坐标值和图像上量算值的偏差,分别评价X和Y方向平均误差,研究不同遥感影像、不同地形地物类别的几何精度。研究发现5 m全色与10 m多光谱影像范围一致,单相机多光谱数据各波段间匹配精度高,5 m全色影像与10 m多光谱影像分别在X方向和Y方向上的误差对点位误差有较大影响。     

基于CBERS-02B的矿区地物信息的提取

应用面向对象分类方法,对山西省平朔露天煤矿进行信息提取。以中巴资源卫星CBERS-02B卫星遥感影像为数据源,利用面向对象分类方法进行多尺度分割并建立分割等级,通过对不同分割尺度的分割结果进行比较,获得最终分割尺度,并结合具体地物的光谱、空间等特征,采用模糊分类中的隶属度函数分类方法,最终将地物分为植被、道路、矿区建筑、煤堆、开采面、废石堆六类。最后使用误差矩阵对分类结果进行精度评价,其总体分类精度达到了88.63%,Kappa系数为0.89。     

基于空间联合的红外舰船目标数据增强方法

针对红外舰船目标图像数据少、获取难度高等问题,结合图像的几何变化以及金字塔生成对抗网络的特征拟合,提出一种几何空间与特征空间联合的红外舰船目标图像数据增强方法。首先,利用基于几何空间的几何变换、混合图像及随机擦除等图像变换方法对红外舰船目标图像进行增强;然后,根据红外舰船图像特点,改进金字塔生成对抗网络（SinGAN）,在生成器引入In-SE通道间注意力机制模块,增强小感受野特征表达,使其更适合用于红外舰船目标;最后,在数据集层面联合基于几何空间的几何数据变换和基于特征空间的生成对抗网络两种方法,完成对原始数据集的数据增强。结果表明:以YOLOv3、SSD、R-FCN和Faster R-CNN目标检测算法为基准模型,开展红外舰船图像数据增强仿真实验,采用增强数据训练的网络模型的舰船目标检测平均精度（mAP）均提高了10%左右,验证了所提方法在小样本红外舰船图像数据增强方面的可行性,为提高红外舰船目标检测算法提供了数据基础。     

中巴地球资源卫星数据产品应用于奥运场馆

中国资源卫星应用中心根据北京奥组委及奥运安保部门等单位的任务需要，结合各场馆所在城市的GPS数据，利用CBERS-02B搭载的高分辨率相机及CCD相机对奥运场馆及周边地区进行成像；根据CBERS-02B星轨道特性，结合气象部门的天气预报，主动安排制定奥运场馆的成像计划，并有针对性地成像，以满足北京奥组委及奥运安保部门的需要。     

中巴地球资源卫星02B星在南方雪灾监测中发挥重要作用

一月中旬雪灾以来，根据国防科工委领导要求，中国资源卫星应用中心紧急启动灾害应急机制，CBERS-02B卫星于1月29、30、31日连续获取了受灾地区图像，并及时将提取的积雪覆盖信息报送国家减灾中心，为抗灾救灾及灾后重建提供了决策依据。     

一种应用于图像配准中的点特征匹配算法

点特征匹配在机器视觉、图像配准等领域中有着重要的应用.针对空间存在较大仿射几何差异的图像中的点特征匹配问题,提出了一种利用马氏距离仿射不变性进行约束的松弛匹配算法,并将该算法应用于遥感图像配准中.实验结果表明,算法可以很好的完成点特征匹配,匹配点对数量充足且具备很高的正确率,从而可以保证图像配准的精度.     

利用MODIS数据进行海岸带卫星图像大气校正

提出一种利用同步MODIS图像的水体像元反演出混浊水域上空气溶胶光学特性的算法.在晴空无云的条件下,假设一定范围内的海岸带上空的大气和水体上空的大气一致,借助6S辐射传输模型,并考虑临近像元效应,利用反演出的气溶胶光学特性对卫星海岸带图像进行大气校正的方法,给出了应用该方法对我国沿海地区QuickBird-2卫星图像和CBERS-02卫星图像进行大气订正的结果,并对反演结果进行了比较分析.实验证明,利用MODIS图像进行海岸带卫星图像大气校正取得了很好的效果,该方法无需地面实测数据,具有很高的适用性.     

MOMS—2P型CCD线阵立体扫描仪的几何标定

德国航空-航天科学研究院光电研究所光学遥感部承担对MOMS-2P型模块式光电多光谱扫描仪的几何标定任务。1993年春,在执行历时10天的D2飞行任务时,首次用MOMS-02型扫描仪在空间沿飞行方向记录三重立体图像,获得一系列摄影有效数据,验证了像具有小于10m精度的数字地形模型那样产生立体照片的能力。此后,对MOMS-02扫描仪进行改进,使其适用于在俄罗斯MIR空间站的PRIRODA轨道仓环境下重新飞行。除MOMS-2P扫描仪外,     

中巴地球资源02星CCD图像的大气校正研究

利用LANDSAT-5的专题制图仪(TM)对中巴地球资源卫星(CBERS)-02的CCD1～4波段进行交叉定标,得到了CCD1～4波段的参考定标系数。利用该定标系数并应用气象数据和ATCOR3软件对CBERS-02的CCD数据进行大气校正;对比大气修正前后图像的清晰度和归一化的植被指数。结果表明,大气校正增强了图像的对比度,归一化植被指数(NDVI)的均值明显提高,增大了高植被覆盖区与低植被覆盖区NDVI的差别,植被信息更加突出。对于山区崎岖地表状况下,大气校正后,山体的棱角分明,轮廓清晰可见,还原了下垫面的原貌,有利于遥感信息的提取。     

Dequantizing image orientation

We address the problem of computing a local orientation map in a digital image. We show that standard image gray level quantization causes a strong bias in the repartition of orientations, hindering any accurate geometric analysis of the image. In continuation, a simple dequantization algorithm is proposed, which maintains all of the image information and transforms the quantization noise in a nearby Gaussian white noise (we actually prove that only Gaussian noise can maintain isotropy of orientations). Mathematical arguments are used to show that this results in the restoration of a high quality image isotropy. In contrast with other classical methods, it turns out that this property can be obtained without smoothing the image or increasing the signal-to-noise ratio (SNR). As an application, it is shown in the experimental section that, thanks to this dequantization of orientations, such geometric algorithms as the detection of nonlocal alignments can be performed efficiently. We also point out similar improvements of orientation quality when our dequantization method is applied to aliased images.     

Satellite image blind restoration based on surface fitting and multivariate model

Owing to the blurring effect from atmosphere and camera system in the satellite imaging, a blind image restoration algorithm is proposed which includes the modulation transfer function （MTF） estimation and the image restoration. In the MTF estimation stage, based on every degradation process of satellite imaging-chain, a combined parametric model of MTF is given and used to fit the surface of normalized logarithmic amplitude spectrum of degraded image. In the image restoration stage, a maximum a posteriori （MAP） based edge-preserving image restoration method is presented which introduces multivariate Laplacian model to characterize the prior distribution of wavelet coefficients of original image. During the image restoration, in order to avoid solving high nonlinear equations, optimization transfer algorithm is adopted to decom- pose the image restoration procedure into two simple steps： Landweber iteration and wavelet thresholding denoising. In the numerical experiment, the satellite image restoration results from SPOT-5 and high resolution camera （HR） of China ＆ Brazil earth resource satellite （CBERS-02B） ane compared, and the proposed algorithm is superior in the image edge preservation and noise inhibition.     

Stochastic differential equations and geometric flows

In previous years, curve evolution, applied to a single contour or to the level sets of an image via partial differential equations, has emerged as an important tool in image processing and computer vision. Curve evolution techniques have been utilized in problems such as image smoothing, segmentation, and shape analysis. We give a local stochastic interpretation of the basic curve smoothing equation, the so called geometric heat equation, and show that this evolution amounts to a tangential diffusion movement of the particles along the contour. Moreover, assuming that a priori information about the shapes of objects in an image is known, we present modifications of the geometric heat equation designed to preserve certain features in these shapes while removing noise. We also show how these new flows may be applied to smooth noisy curves without destroying their larger scale features, in contrast to the original geometric heat flow which tends to circularize any closed curve.     

Reduced dose and improved image quality with a computerized line-scan radiography system

Diode-array digital radiography (DADR) is a patented technology which shows promise for producing improved radiographic image quality while reducing the X-ray dose to the patient. DADR combines geometric scatter rejection with a scintillator and solid-state photodiode array detector of large dynamic range to create diagnostic X-ray images which makes efficient use of the patient dose. Engineering measurements were made to determine the basic characteristics of the system. Engineering measurements were made to determine the basic characteristics of the system. A number of image postprocessing techniques were examined for further improving the image quality of the DADR system. Unsharp masking, local contrast stretching, and modified local contrast stretching were used. The modified local contrast stretching has produced the best results to date, with image quality exceeding that of standard film/screen chest images. Images have been postprocessed using facilities of the Pittsburgh Supercomputer Center.     

多光谱遥感卫星图像的精确配准方法研究

针对一组多光谱遥感图像中,各谱段图像之间配准不一致的问题,本文提出了一种基于特征点的快速自动配准方法。在图像信息熵的基础上,利用环形移动窗口,自动快速寻找感兴趣区域, 并利用尺度不变特征转换（SIFT）算法提取特征。为提高精度,文中对特征初匹配方法作了改进,并用余弦定理和空间距离约束条件剔除误匹配点,之后提取最稳定的特征点对计算变换参数,完成配准。最后根据配准前后图像的互信息和特征点的均方根误差（RMSE）来衡量配准的程度。通过对大量中巴地球资源卫星拍摄的多光谱图像进行实验,该方法能达到亚像素级配准精度,并能快速对各谱段图像进行配准。