对于尺寸小于雷达距离分辨率的太空碎片进行雷达成像,以前提出的方法只有SRDI(Single Range Doppler Interferometry)。该文针对太空碎片运动特点,给出了一种单距离匹配滤波太空碎片成像方法。该方法利用一个距离单元横向回波数据经不...对于尺寸小于雷达距离分辨率的太空碎片进行雷达成像,以前提出的方法只有SRDI(Single Range Doppler Interferometry)。该文针对太空碎片运动特点,给出了一种单距离匹配滤波太空碎片成像方法。该方法利用一个距离单元横向回波数据经不同旋转半径参考信号匹配滤波后得到太空碎片二维像。仿真结果表明这种方法比SRDI方法计算量少、成像效果好。展开更多
针对太空碎片围绕其主轴进行高速自旋运动的特点,利用单距离匹配滤波(Single Range Matching Filtering,SRMF)方法可以实现小尺寸太空碎片的逆合成孔径雷达成像。通过相干CLEAN技术的引入,SRMF-CLEAN算法可有效地解决傅里叶变换带来的...针对太空碎片围绕其主轴进行高速自旋运动的特点,利用单距离匹配滤波(Single Range Matching Filtering,SRMF)方法可以实现小尺寸太空碎片的逆合成孔径雷达成像。通过相干CLEAN技术的引入,SRMF-CLEAN算法可有效地解决傅里叶变换带来的高旁瓣问题。然而在低信噪比情况下,利用SRMF-CLEAN成像方法提取的散射点位置误差偏大,甚至某些弱散射点无法被提取;当散射点距离较近时,该算法提取的散射点中存在虚假散射点的情况。针对此,提出了一种改进的SRMF-CLEAN成像方法,该方法利用序列CLEAN技术可以有效地解决高旁瓣、虚假散射点问题。仿真实验结果验证了新方法的有效性。展开更多
The randomly intermittent spectra (RIS) signal is employed to combat spectrum congestion in radar and other radio services to evade the external interferences in high-frequency (HF) and ultrahigh-frequency (UHF) bands...The randomly intermittent spectra (RIS) signal is employed to combat spectrum congestion in radar and other radio services to evade the external interferences in high-frequency (HF) and ultrahigh-frequency (UHF) bands. However, the spectra discontinuity of the signal gets rise to high range sidelobes when matching the reflected echo, which is much more difficult for targets detection. So it is indispensable to investigate the technique for sidelobes suppression of the range profile when RIS signal is utilized, This paper introduced a new processing technique based on time domain filtering to lower the range sidelobes. A robust and effetive algorithm is adopted to solve the coefficients of the filter, and the restriction on the desired response of the filter is derived. The simulation results show that the peak range sidelobe can be reduced to -27 dB from -9.5 dB while the frequency band span (FBS) is 200 kHz.展开更多
To cope with the problem of tracking a human head in a complicated scene,we propose a method that adopts human skin color and hair color integrated with a kind of particle filter named condensation algorithm.Firstly,a...To cope with the problem of tracking a human head in a complicated scene,we propose a method that adopts human skin color and hair color integrated with a kind of particle filter named condensation algorithm.Firstly,a novel method is presented to set up human head color model using skin color and hair color separately based on region growing.Compared with traditional human face model,this method is more precise and works well when human turns around and the face disappears in the image.Then a novel method is presented to use color model in condensation algorithm more effectively.In this method,a combination of edge detection result,color segmentation result and color edge detection result in an Omega window is used to measure the scale and position of human head in condensation.Experiments show that this approach can track human head in complicated scene even when human turns around or the distance of tracking a human head changes quickly.展开更多
Based on the smart home and facial expression recognition, this paper presents a cognitive emotional model for eldercare robot. By combining with Gabor filter, Local Binary Pattern algorithm(LBP) and k-Nearest Neighbo...Based on the smart home and facial expression recognition, this paper presents a cognitive emotional model for eldercare robot. By combining with Gabor filter, Local Binary Pattern algorithm(LBP) and k-Nearest Neighbor algorithm(KNN) are facial emotional features extracted and recognized. Meanwhile, facial emotional features put influence on robot's emotion state, which is described in AVS emotion space. Then the optimization of smart home environment on the cognitive emotional model is specially analyzed using simulated annealing algorithm(SA). Finally, transition probability from any emotional state to a state of basic emotions is obtained based on the cognitive reappraisal strategy and Euclidean distance. The simulation and experiment have tested and verified the effective in reducing negative emotional state.展开更多
文摘对于尺寸小于雷达距离分辨率的太空碎片进行雷达成像,以前提出的方法只有SRDI(Single Range Doppler Interferometry)。该文针对太空碎片运动特点,给出了一种单距离匹配滤波太空碎片成像方法。该方法利用一个距离单元横向回波数据经不同旋转半径参考信号匹配滤波后得到太空碎片二维像。仿真结果表明这种方法比SRDI方法计算量少、成像效果好。
文摘针对太空碎片围绕其主轴进行高速自旋运动的特点,利用单距离匹配滤波(Single Range Matching Filtering,SRMF)方法可以实现小尺寸太空碎片的逆合成孔径雷达成像。通过相干CLEAN技术的引入,SRMF-CLEAN算法可有效地解决傅里叶变换带来的高旁瓣问题。然而在低信噪比情况下,利用SRMF-CLEAN成像方法提取的散射点位置误差偏大,甚至某些弱散射点无法被提取;当散射点距离较近时,该算法提取的散射点中存在虚假散射点的情况。针对此,提出了一种改进的SRMF-CLEAN成像方法,该方法利用序列CLEAN技术可以有效地解决高旁瓣、虚假散射点问题。仿真实验结果验证了新方法的有效性。
文摘The randomly intermittent spectra (RIS) signal is employed to combat spectrum congestion in radar and other radio services to evade the external interferences in high-frequency (HF) and ultrahigh-frequency (UHF) bands. However, the spectra discontinuity of the signal gets rise to high range sidelobes when matching the reflected echo, which is much more difficult for targets detection. So it is indispensable to investigate the technique for sidelobes suppression of the range profile when RIS signal is utilized, This paper introduced a new processing technique based on time domain filtering to lower the range sidelobes. A robust and effetive algorithm is adopted to solve the coefficients of the filter, and the restriction on the desired response of the filter is derived. The simulation results show that the peak range sidelobe can be reduced to -27 dB from -9.5 dB while the frequency band span (FBS) is 200 kHz.
文摘To cope with the problem of tracking a human head in a complicated scene,we propose a method that adopts human skin color and hair color integrated with a kind of particle filter named condensation algorithm.Firstly,a novel method is presented to set up human head color model using skin color and hair color separately based on region growing.Compared with traditional human face model,this method is more precise and works well when human turns around and the face disappears in the image.Then a novel method is presented to use color model in condensation algorithm more effectively.In this method,a combination of edge detection result,color segmentation result and color edge detection result in an Omega window is used to measure the scale and position of human head in condensation.Experiments show that this approach can track human head in complicated scene even when human turns around or the distance of tracking a human head changes quickly.
基金supported by National Natural Science Foundation of China (Normal Project No. 61170115), (Key Project No.61432004)National Key Technologies R&D Program of China (No.2014BAF08B04)the Foundation of Beijing Engineering and Technology Center for Convergence Networks and Ubiquitous Services
文摘Based on the smart home and facial expression recognition, this paper presents a cognitive emotional model for eldercare robot. By combining with Gabor filter, Local Binary Pattern algorithm(LBP) and k-Nearest Neighbor algorithm(KNN) are facial emotional features extracted and recognized. Meanwhile, facial emotional features put influence on robot's emotion state, which is described in AVS emotion space. Then the optimization of smart home environment on the cognitive emotional model is specially analyzed using simulated annealing algorithm(SA). Finally, transition probability from any emotional state to a state of basic emotions is obtained based on the cognitive reappraisal strategy and Euclidean distance. The simulation and experiment have tested and verified the effective in reducing negative emotional state.
