3D information from 2D images recorded in the European Modular Cultivation System on the ISS

The European Modular Cultivation System (EMCS) on the ISS allows long-term biological experiments, e.g. on plants. Video cameras provide near real-time 2D images from these experiments. A method to obtain 3D coordinates and stereoscopic images from these 2D images has been developed and is described in this paper. The procedure was developed to enhance the data output of the MULTIGEN-1 experiment in 2007. One of the main objectives of the experiment was to study growth movements of the Arabidopsis plants and the effect of gravity on these. 3D data were important during parts of the experiment and the paper presents the method developed to acquire 3D data, the accuracy of the data, limitations to the technique and ways to improve the accuracy. Sequences of 3D data obtained from the MULTIGEN-1 experiment are used to illustrate the potential of this newfound capability of the EMCS. In the experiment setup, a positional depth accuracy of about ±0.4 mm for relative object distances and an absolute depth accuracy of about ±1.4 mm for time dependent phenomena was reached. The ability to both view biological specimens in 3D as well as obtaining quantitative 3D data added greatly to the scientific output of the MULTIGEN-1 experiment. The uses of the technique to other researchers and their experiments are discussed.     

Effects of lighting and air movement on temperatures in reproductive organs of plants in a closed plant growth facility

Temperature increases in plant reproductive organs such as anthers and stigmas could cause fertility impediments and thus produce sterile seeds under artificial lighting conditions without adequately controlled environments in closed plant growth facilities. There is a possibility such a situation could occur in Bioregenerative Life Support Systems under microgravity conditions in space because there will be little natural convective or thermal mixing. This study was conducted to determine the temperature of the plant reproductive organs as affected by illumination and air movement under normal gravitational forces on the earth and to make an estimation of the temperature increase in reproductive organs in closed plant growth facilities under microgravity in space. Thermal images of reproductive organs of rice and strawberry were captured using infrared thermography at air temperatures of 10–11 °C. Compared to the air temperature, temperatures of petals, stigmas and anthers of strawberry increased by 24, 22 and 14 °C, respectively, after 5 min of lighting at an irradiance of 160 W m⁻² from incandescent lamps. Temperatures of reproductive organs and leaves of strawberry were significantly higher than those of rice. The temperatures of petals, stigmas, anthers and leaves of strawberry decreased by 13, 12, 13 and 14 °C, respectively, when the air velocity was increased from 0.1 to 1.0 ms⁻¹. These results show that air movement is necessary to reduce the temperatures of plant reproductive organs in plant growth facilities.     

基于CT的泡沫铝三维细观模型重建及应用

为了建立更加真实的闭孔泡沫铝三维细观分析模型,提出了一种基于计算机层析成像（CT）的有限元模型构建新方法。首先,对CT扫描得到的泡沫铝试件的扫描图像进行Otsu算法分析,确定了区分基体材料和空气的灰度最佳阈值。其次,基于映射网格思想直接从扫描图像生成了试件的有限元分析模型,实现了泡沫金属三维细观分析模型的重建。最后,以此为基础进行了泡沫铝试件准静态压缩和动态冲击试验的数值模拟,结果表明,准静态压缩下泡沫铝的内部变形随机分布于整个试件,且与其三维结构密切相关;而动态冲击下变形在冲击端附近首先发生,体现出显著的局部化效应。本文方法能真实地描述泡沫金属内部的细观结构,实现了对泡沫铝试件在准静态压缩和动态冲击作用下的受力、变形与破坏过程更加详细的模拟分析。      

基于衍射图像的大型光学镜面在位检测

介绍了相位恢复测量系统的软硬件实现原理。构建了由CCD移动平台等硬件装置和基于GS迭代算法的软件程序组成的实验平台。并对一面口径500mm的球面反射镜进行了在位加工环境下的测量实验。测试结果与干涉测量相比较表明测量数据准确,精度满足光学镜面研抛加工要求。     

Spiral eddies in the Baltic,Black and Caspian seas as seen by satellite radar data

Despite spiral eddies were first seen on the sea surface more than 40 years ago, there is still a lot of uncertainty concerning these eddies. The present paper is aimed to provide the comprehensive results on the occurrence and statistics of small-scale eddies in the three inner seas (the Baltic, Black and Caspian) using satellite synthetic aperture radar (SAR) images. The dataset used includes over 2000 medium resolution Envisat ASAR and ERS-2 SAR images obtained in 2009–2010 in the different parts of the seas mentioned. As a result of the analysis performed ∼14,000 vortical structures were detected. 71% of them were visualized due to surfactant films (“black” eddies), while 29% due to wave/current interactions (“white” eddies). Practically all the eddies detected were cyclonically rotating. Their diameter was within 1–20 km. Characteristic size of the “black” eddies in all the basins was discovered to be less than that of the “white” eddies. Characteristic eddy size for the Baltic, Black and Caspian seas proved to be strictly proportional to the values of the baroclinic Rossby radius of deformation typical for these basins. The “black” eddies did not demonstrate a significant connection with the basin- and meso-scale surface circulation of the seas. Most of the “white” eddies detected were attributed to the zones with the most intense drift currents, i.e. those along the western boundaries and (in the Baltic Sea only) in the elongated parts of the basin.     

Relationships between soil properties of the abandoned fields and spectral data derived from the advanced spaceborne thermal emission and reflection radiometer (ASTER)

The structural transformation of Polish agriculture after 1989 has been leading to significant changes in land use. As a result a large part of formerly ploughed fields lies abandoned and they occur across considerable variability in soil typological units. Accurate information about soil conditions within the abandoned fields facilitates proper management in the new socio-economic situation. Such information can be collected using satellite images since the structure and condition of the vegetation growing on the abandoned fields reflects soil properties. The objective of this study is to evaluate the relationships between physical and chemical attributes of soil within the abandoned fields and spectral reflectance patterns recorded by ASTER sensors onboard Terra Satellite. Soil samples were collected at five abandoned fields which have not been ploughed since 2000 and analyzed in the laboratory to determine their physical and chemical properties. Nine ASTER nearly cloud-free pictures were used for this study in order to derive the remote-sensing attributes of the abandoned fields. In order to evaluate the relationships between soil fertility and remotely sensed data, partial least-squares (PLS) and a multiple linear regression (MLR) analysis between these two datasets were carried out. In the regression analysis, only soil TEB (total exchangeable bases) stock in the whole profile displayed the highest correlation with remotely sensed data acquired in April and May and the best predictors were NDVI and LSWI vegetation indices.     

细缝裁减和非均匀映射结合的图像自适应方法

采用将细缝裁减和非均匀映射相结合的图像尺寸自适应框架,提出了一种基于内容的图像重要信息变形的度量方法.首先提取原始图像的重要性像素点,利用细缝裁减去掉一条像素细缝后,相应的重要性像素点会被更新.对于图像中保留的重要性像素点,计算它们的子图像平均偏差(ADSI,Average Difference of Sub Images);对于被移除的重要性像素点,计算它们的平均丢失能量(ALE,Average Lost Energy).通过ADSI和ALE可计算出重要信息变形的度量函数(IIDF,Important Information Deformation Function)的值,通过分析IIDF的趋势得到细缝裁减的终止条件,然后改用非均匀映射方法(non-homogeneous warping)将图像自适应到目标尺寸.实验结果证明,新方法处理的结果图像重要区域变形较小,并且计算效率比较高.     

基于分水岭变换的单幅高分辨率SAR图像建筑物检测方法

提出了一种从单幅高分辨率SAR图像中检测建筑物的算法框架。该框架主要以应用 标记的分水岭变换为基础,针对SAR图像中建筑物所具有的强回波特性与典型的形状特征, 主要采用CFAR检测和文中提出的方向相关分析方法得到标记图像,利用最小强制技术和标记 图像修改原始图像的梯度图,对修改后的梯度图作分水岭变换得到建筑物目标的边界轮廓。 该方法能够引入建筑物目标的特性同时克服分水岭变换固有的过分割缺陷。文中对不同场景 的高分辨率SAR图像进行了实验,实验结果表明,即使在建筑物分布密集的情况下,本文算 法也能正确完整地检测出绝大多数目标,检测率高而虚警率低。     

基于混合Contourlet变换和主成分变换的高光谱图像融合

针对高光谱图像波段多、存在噪声干扰等特点,提出了一种混合Contourlet和主成 分 分析（principal component analysis, 简称PCA）变换的高光谱图像融合方法。首先将多 个波段的高光谱图像进行Contourlet变换,得到系列多尺度、方向各异的子带系数,然后利 用PCA变换对各子带系数分别进行自适应融合处理。实验结果表明该算法可以有效地进行高 光谱图像融合,消除噪声干扰,获得比直接应用Contourlet变换和PCA变换更好的融合效果 。〖JP〗     

金属橡胶冲击隔振系统试验

金属橡胶抗冲击隔振器利用干摩擦和弹性变形消耗冲击能量,实现缓冲减振的目的.针对某飞行器抗冲击隔振的需求,设计了金属橡胶抗冲击隔振器,并进行了冲击试验,结果表明最大加速度响应和冲击隔离系数随着冲击时间增加而加大,同时冲击隔离系数受冲击载荷的大小影响.在冲击载荷较小时冲击隔离系数随冲击载荷增加而减小,超过一定范围后,冲击隔离系数随着冲击载荷的增加而加大.