A correlation tracking algorithm based on template partition motion estimation proposed for improving real time performance of the conventional correlation matching algorithms. The target trajectory fitted using the l...A correlation tracking algorithm based on template partition motion estimation proposed for improving real time performance of the conventional correlation matching algorithms. The target trajectory fitted using the least square with equal space in whole interval and the target prediction point is found out. According to the requirements of block motion estimation(BME) algorithm,the template divided into some macro blocks. The searching process is conducted by using diamond search algorithm around the prediction point and the optimal motion vector of each block is calculated. A point corresponding to the motion vector with the best matching is taken as a rough matching point of the template. The relation of relative position between the block with matching point and the searching area determined to decide whether to conduct precise matching search or to construct a new search area in the gradient direction. The target tracking experiment results show that over 70% time cost can be reduced caompared with the conventional correlation matching algorithm based on full search method.展开更多
This study evaluated the myocardial strain and aortic elasticity in patients with bicuspid aortic valve(BAV) and then investigated the relation between them. Thirty-nine patients(30 males; mean age 44±19 years...This study evaluated the myocardial strain and aortic elasticity in patients with bicuspid aortic valve(BAV) and then investigated the relation between them. Thirty-nine patients(30 males; mean age 44±19 years; range 6 to 75 years) with BAV were recruited as BAV group, and 29 age- and sex-matched healthy controls(21 males; mean age 42±11 years; range 20 to 71 years) served as control group. Aortic strain, distensibility and stiffness index were derived using M-mode echocardiography. Left ventricular global myocardial strain was acquired with speckle-tracking echocardiography. Correlation between aortic elasticity and myocardial strain was also analyzed. The results showed that aortic stiffness was higher(17.5±14.0 vs. 5.3±2.7, P〈0.001), and aortic strain(4.9±4.7 vs. 11.0±4.1, P〈0.001) and distensibility(1.8±2.1 vs. 3.7±1.6, P〈0.001) were lower significantly in BAV group than in control group. Global circumferential strain(–19.1±4.2 vs. –22.5±3.7, P〈0.001), radial stain(29.8±14.9 vs. 38.0±8.8, P〈0.001) and longitudinal stain(–18.4±3.4 vs. –20.8±3.5, P〈0.001) were significantly lower in BAV group than in control group. There was weak association between aortic elasticity and myocardial strain. These findings indicated BAV patients manifest reduced myocardial strain which had weak relationship with aortic elastic lesion.展开更多
The downlink frame structure for beyond 3G mobile communication systems is presented. Beyond 3G systems utilize the OFDM technique. However, a problem encountered in OFDM is that channel dispersion destroys orthogonal...The downlink frame structure for beyond 3G mobile communication systems is presented. Beyond 3G systems utilize the OFDM technique. However, a problem encountered in OFDM is that channel dispersion destroys orthogonality between carriers, caushag inter-symbol interference. It is also sensitive to high peak to mean power ratio (PAPR). Therefore it spends much time on obtaining frequency, time, and frame synchronization. This paper proposes to add a frame synchronization channel in the time domain to overcome the shortcoming of OFDM. As transmitter diversity improves the system performance, beyond 3G systems employ space-time block coded (STBC). Fast cell search algorithm including slot synchronization, frame synchronization and cell ID identification is then discussed, which is based on the frame synchronization channel in transmitter diversity systems. Detection and false alarm probabilities in AWGN and Rayleigh channels are analyzed, and the mean acquisition time is obtained. Computer simulations are conducted to evaluate the performance of the cell search algorithm under different channel conditions.展开更多
This Letter proposes a coordinate difference homogenization matching method to solve motion influence in three-dimensional(3D) range-intensity correlation laser imaging. Firstly, features and feature pairs of gate i...This Letter proposes a coordinate difference homogenization matching method to solve motion influence in three-dimensional(3D) range-intensity correlation laser imaging. Firstly, features and feature pairs of gate images are obtained by speeded-up robust figures and bi-directional feature matching methods. The original mean value of the feature-pair coordinate differences is calculated. Comparing the coordinate differences with the original mean value, the wrong feature pairs are removed, and then an optimized mean value is updated. The final feature-pair coordinates are re-registered based on the updated mean value. Thus, an accurate transformation is established to rectify motion gate images for 3D reconstruction. In the experiment, a 3D image of a tower at 780 m is successfully captured by our laser gated imaging system on a pan-tilt device.展开更多
基金Sponsored by the National Defense Pre-Research Foundation of China
文摘A correlation tracking algorithm based on template partition motion estimation proposed for improving real time performance of the conventional correlation matching algorithms. The target trajectory fitted using the least square with equal space in whole interval and the target prediction point is found out. According to the requirements of block motion estimation(BME) algorithm,the template divided into some macro blocks. The searching process is conducted by using diamond search algorithm around the prediction point and the optimal motion vector of each block is calculated. A point corresponding to the motion vector with the best matching is taken as a rough matching point of the template. The relation of relative position between the block with matching point and the searching area determined to decide whether to conduct precise matching search or to construct a new search area in the gradient direction. The target tracking experiment results show that over 70% time cost can be reduced caompared with the conventional correlation matching algorithm based on full search method.
基金supported by the National Natural Science Foundation of China(No.81571695)
文摘This study evaluated the myocardial strain and aortic elasticity in patients with bicuspid aortic valve(BAV) and then investigated the relation between them. Thirty-nine patients(30 males; mean age 44±19 years; range 6 to 75 years) with BAV were recruited as BAV group, and 29 age- and sex-matched healthy controls(21 males; mean age 42±11 years; range 20 to 71 years) served as control group. Aortic strain, distensibility and stiffness index were derived using M-mode echocardiography. Left ventricular global myocardial strain was acquired with speckle-tracking echocardiography. Correlation between aortic elasticity and myocardial strain was also analyzed. The results showed that aortic stiffness was higher(17.5±14.0 vs. 5.3±2.7, P〈0.001), and aortic strain(4.9±4.7 vs. 11.0±4.1, P〈0.001) and distensibility(1.8±2.1 vs. 3.7±1.6, P〈0.001) were lower significantly in BAV group than in control group. Global circumferential strain(–19.1±4.2 vs. –22.5±3.7, P〈0.001), radial stain(29.8±14.9 vs. 38.0±8.8, P〈0.001) and longitudinal stain(–18.4±3.4 vs. –20.8±3.5, P〈0.001) were significantly lower in BAV group than in control group. There was weak association between aortic elasticity and myocardial strain. These findings indicated BAV patients manifest reduced myocardial strain which had weak relationship with aortic elastic lesion.
基金Project supported by National Natural Science Foundation of China(Grant No . 60272079) , and National High-Technology Researchand Development Program(Grant No .863-2003 AA123310)
文摘The downlink frame structure for beyond 3G mobile communication systems is presented. Beyond 3G systems utilize the OFDM technique. However, a problem encountered in OFDM is that channel dispersion destroys orthogonality between carriers, caushag inter-symbol interference. It is also sensitive to high peak to mean power ratio (PAPR). Therefore it spends much time on obtaining frequency, time, and frame synchronization. This paper proposes to add a frame synchronization channel in the time domain to overcome the shortcoming of OFDM. As transmitter diversity improves the system performance, beyond 3G systems employ space-time block coded (STBC). Fast cell search algorithm including slot synchronization, frame synchronization and cell ID identification is then discussed, which is based on the frame synchronization channel in transmitter diversity systems. Detection and false alarm probabilities in AWGN and Rayleigh channels are analyzed, and the mean acquisition time is obtained. Computer simulations are conducted to evaluate the performance of the cell search algorithm under different channel conditions.
基金supported by the National Key Research and Development Program of China(No.2016YFC0500103)the Youth Innovation Promotion Association CAS(No.2017155)the Scientific Instrument Development Project from Capital Science and Technology Condition Platform(No.Z171100002817002)
文摘This Letter proposes a coordinate difference homogenization matching method to solve motion influence in three-dimensional(3D) range-intensity correlation laser imaging. Firstly, features and feature pairs of gate images are obtained by speeded-up robust figures and bi-directional feature matching methods. The original mean value of the feature-pair coordinate differences is calculated. Comparing the coordinate differences with the original mean value, the wrong feature pairs are removed, and then an optimized mean value is updated. The final feature-pair coordinates are re-registered based on the updated mean value. Thus, an accurate transformation is established to rectify motion gate images for 3D reconstruction. In the experiment, a 3D image of a tower at 780 m is successfully captured by our laser gated imaging system on a pan-tilt device.