搜索结果: 1-15 共查到“工学 Radon”相关记录36条 . 查询时间(0.056 秒)
Radon Decay Product Aerosols in Ambient Air
Radon Decay products 214Pb 212Pb 210Pb Radioactive aerosols Cascade impactors 1-ACFM AMAD Residence time
2016/3/29
The aerodynamic size distributions of radon decay product aerosols, i.e. 214Pb, 212Pb, and 210Pb were measured using low-pressure
(LPI) as well as conventional low-volume 1-ACFM and high-volume (HVI)...
提出一种基于Radon修正离散线性调频傅里叶变换(Radonmodified discrete chirp Fourier transform,RMDCFT)的空间高速机动目标检测与参数估计的方法。该方法在目标运动参数范围内进行搜索,将目标数据从距离单元〖CD*2〗慢时间域中取出并进行相应匹配变换处理,在补偿回波数据相位并进行相参积累以用于目标检测的基础上同时得到目标速度和加速度的估计结果。〖...
Measuring radon in soil gas and groundwaters: a review
radon soil gas groundwaters earthquake prediction instrumentation
2015/9/2
Instruments for the measurements of radon and its decay products in earthquake research are based mostly on
the detection of alpha particles. The devices and methods used depend on whether the techni...
Curvelets and Reconstruction of Images from Noisy Radon Data
Ill-Posed Inverse Problems Regularization Singular Value Decomposition Radon Transform Deconvolution Edge Edge-Preserving Regularization Wavelet-Vaguelette-Decomposition
2015/6/17
The problem of recovering an input signal from noisy and linearly distorted data arises in many different areas of scientific investigation; e.g., noisy Radon inversion (tomography) is a problem of sp...
基于短时迭代自适应-逆Radon变换的微多普勒提取方法
弹道目标 微多普勒 迭代自适应(IAA) 逆Radon变换(IRT)
2016/12/30
对于频率交叠严重且频率成分接近的多分量信号,常用的短时傅里叶变换(Short Time Fourier Transform,STFT)和S方法(S-Method,SM)频率分辨能力不足,重构精度低.针对该问题,本文结合逆Radon变换提出了基于短时迭代自适应-逆Radon变换(Short Time Iterative Adaptive Approach-Inverse Radon Transfor...
长时间相参积累技术是提高雷达对微弱运动目标探测能力的重要手段之一,本文在分析动目标回波信号距离和多普勒徙动的基础上,提出基于Radon-分数阶傅里叶变换(RFRFT)的长时间相参积累方法.该方法根据预先设定的运动参数搜索范围,提取位于距离-慢时间二维平面中的目标观测值,然后在FRFT域进行匹配和积累,并通过构建的RFRFT域检测单元图实现对非匀速运动目标的检测.该方法能够同时补偿距离和多普勒徙动,...
为提高短模糊尺度下的运动模糊参数估计精度,提出了一种改进的基于Radon 变换的频域估计算法。算法对运动模糊图像傅里叶变换频谱图做Radon变换,利用运动模糊图像频谱图 在垂直于条纹方向下Radon 变换时为明暗投影线的特性,在Radon变换图中确定明暗投影线,由该 投影线对应的Radon变换角度和运动模糊图像的分辨率求解运动模糊参数。对Lena图像的仿真 结果表明:当模糊尺度为5 ~ 10 时,...
长时间相干积累方法Radon-Fourier变换(RFT)中盲速旁瓣(BSSL)现象会导致雷达虚警增加、目标检测性能降低。针对BSSL问题,给出了一种基于多输入多输出(MIMO)雷达多载频设计的BSSL抑制方法。首先根据载频与BSSL分布的关系,详细推导了BSSL不交叠的约束条件;然后基于该约束条件给出了具体的载频设计公式。利用设计的载频可得到具有不交叠BSSL的两个RFT输出,通过联合处理这两个...
An Indoor Radon Survey in Three Different Climate Regions in Mexico, and the Influence of Climate in the Obtained Values
Radon Indoor Radon Climate Influence Nuclear Tracks Methodology
2013/3/13
In this paper we present the results of a survey of indoor radon concentration levels in Mexico. In order to investigate whether differences in climate translate into significant differences in indoor...
Environmental Distribution of the Radon in a Heavily Populated Area: Preliminary Hazard Evaluation and Inference on Risk Factors in Pescara, Central Italy
Radioactive Pollution Radon Measurements Radon Distribution Radon Risk Analysis Pescara-Italy
2013/3/12
The presence of ionizing sources is a high-risk condition if related to a poor management of the hygiene and health of the anthropic environment. Increased hazard derives from the addition of artifici...
CITY STRUCTURE ANALYSIS ON QUICKBIRD IMAGERY BY MULTISCALE RADON TRANSFORMATION
Quickbird imagery radon transformation city structure multiscale analysis
2014/6/5
The radon transformation is a proven image analysis technique in medical image processing, although there are some applications
with satellite images. Among these applications maybe the most interes...
Radon变换与功率谱结合的PSA图像倾斜度自动校正算法
图像预处理 倾斜校正 radon变换 功率谱估计
2014/4/28
针对卟啉传感阵列(PSA)图像中卟啉点阵列可能发生倾斜的现象,设计了一种自动校正算法。算法之初对图像进行滤波、对比度增强操作,并求得图像的二值形态学边界,利用此二值边界图像作为求取倾斜角度运算的输入,减少了噪声的影响,同时也降低了时间的花费;而后利用radon变换与功率谱结合的方法来求取倾斜角度,解决了单纯的radon变换法易受空域噪声的影响,使得校正的精度大大提高。利用该算法对卟啉传感阵列图像进...
复制粘贴(Copy-Move)是一种极为常见的图像篡改方式。为了快速有效地检测图像经过旋转、缩放等操作后的篡改图像,本文提出了一种基于Radon和解析Fourier-Mellin变换的篡改图像盲检测方法。文章首先对图像进行分块,之后将图像块进行Radon和解析Fourier-Mellin变换,并提取计算变换结果后的矩特征值,最后计算矩特征值的相关性。本文算法不需要对灰度图像进行二值化与归一化处理,...
现有的大多数数字水印算法在设计时过分地强调载体数据中嵌入水印以及在遭受几何攻击之后水印的不可感知性和鲁棒性,而对水印在检测时数字水印的虚警率和漏检率实验分析甚少。如果一个数字水印算法在水印检测时它的虚警率和漏检率很高,即使这种算法具有很好的鲁棒性那么也不能有效地解决版权保护,相反却会引入新的版权纠纷。针对以上提出的问题,提出一种基于Radon变换不变矩的抗几何攻击鲁棒性数字水印可以有效地减少水印的...