Purpose: This study was undertaken to determine if portal-inflow bolus tracking outperforms aortic bolus tracking with respect to the image quality of contrast-enhanced portal venous-phase CT of the liver in patients ...Purpose: This study was undertaken to determine if portal-inflow bolus tracking outperforms aortic bolus tracking with respect to the image quality of contrast-enhanced portal venous-phase CT of the liver in patients without chronic liver damage. Materials and Methods: Contrast-enhanced CT of the liver was performed in 132 consecutive patients without chronic liver damage. Patients were prospectively assigned to three protocols: Protocol A—a portal venous-phase scan delay of 6 seconds after superior mesenteric venous (SMV) enhancement increased by 70 HU or 14 seconds after SMV enhancement was visually confirmed, and Protocols B and C—40 and 50 seconds, respectively, after abdominal aortic enhancement increased by 100 HU. Enhancement (ΔHU) of abdominal aorta, portal trunk, and liver parenchyma and diagnostic acceptability were assessed. Results: ΔHU of aorta was higher for protocol A than for protocols B and C (P P Conclusion: Portal-inflow bolus tracking did not outperform aortic tracking in terms of optimization of portal venous-phase CT in patients without chronic liver damage.展开更多
High-contrast is one of the main advantages in laser projection display, and the method of DCC (Dynamic Contrast Control) is the main way to increase the contrast. Generally, image pre-processing is necessary for elim...High-contrast is one of the main advantages in laser projection display, and the method of DCC (Dynamic Contrast Control) is the main way to increase the contrast. Generally, image pre-processing is necessary for eliminating noise and decreasing the over-highlight. In this paper, we proposed and actualized a method by following 3 steps: Firstly, the original image was analyzed statistically to get the scope of gray-scale distribution and average gray-scale;and then the image was divided into a number of sub-images. The sub-images whose pixels are higher than a certain threshold in both number and range, are applied image segmentation by certain growth rules. The sub-images satisfied with the growth rules are marked 1, and the rests are marked 0. Secondly, the sub-images are uniting. A sub-image has 3 relations between 8 sub-images around it: 1 and 1, 1 and 0, 0 and 0. The sub-images marked 1 are uniting together, and the sub-images marked 0 are uniting together. Without affecting the visual vision, all over-highlight pixels were reduced in a certain proportion. Lastly, based on the application of DCC, the whole image signals were enlarged and the brightness of light sources were reduced, so as to achieve the desired effect in contrast enhancement.展开更多
The electric drive system characteristics of different projects for tracked vehicles are analyzed.For the two most typical projects,the parameters of power,torque and rotating speed and others of drive motor are figur...The electric drive system characteristics of different projects for tracked vehicles are analyzed.For the two most typical projects,the parameters of power,torque and rotating speed and others of drive motor are figured out under the condition of satisfying adequate steering performance of the tracked vehicles.General opinions on the two projects are brought forward and conclusions are drawn.展开更多
雷达在跟踪飞行目标时,常发生跟踪中断的现象。深度学习方法具有强大的学习能力,已被逐渐用于解决中断航迹关联问题。但已有基于深度学习的中断航迹关联方法未能充分考虑新老航迹特征之间的相似性,关联性能仍有待提升。因此提出一种基...雷达在跟踪飞行目标时,常发生跟踪中断的现象。深度学习方法具有强大的学习能力,已被逐渐用于解决中断航迹关联问题。但已有基于深度学习的中断航迹关联方法未能充分考虑新老航迹特征之间的相似性,关联性能仍有待提升。因此提出一种基于深度时间对比的中断航迹关联算法(Track Segment Association based on Deep Temporal Contrasting,TSADTC),包括航迹特征提取模块、时间对比模块、航迹特征对比模块和分类器模块。航迹特征提取模块利用双向长短期记忆网络和编码器-解码器分别对新老航迹进行特征提取;时间对比模块分别使用一条航迹的特征预测另外一条航迹;航迹特征对比模块计算两条航迹的特征差别,并将此差别输入分类器中,以计算两条航迹关联的概率。算法将关联概率最大的航迹对作为关联航迹对。仿真实验表明,TSADTC算法能够有效提高中断航迹关联的正确关联率、错误关联率和航迹漏关联率性能。展开更多
文摘Purpose: This study was undertaken to determine if portal-inflow bolus tracking outperforms aortic bolus tracking with respect to the image quality of contrast-enhanced portal venous-phase CT of the liver in patients without chronic liver damage. Materials and Methods: Contrast-enhanced CT of the liver was performed in 132 consecutive patients without chronic liver damage. Patients were prospectively assigned to three protocols: Protocol A—a portal venous-phase scan delay of 6 seconds after superior mesenteric venous (SMV) enhancement increased by 70 HU or 14 seconds after SMV enhancement was visually confirmed, and Protocols B and C—40 and 50 seconds, respectively, after abdominal aortic enhancement increased by 100 HU. Enhancement (ΔHU) of abdominal aorta, portal trunk, and liver parenchyma and diagnostic acceptability were assessed. Results: ΔHU of aorta was higher for protocol A than for protocols B and C (P P Conclusion: Portal-inflow bolus tracking did not outperform aortic tracking in terms of optimization of portal venous-phase CT in patients without chronic liver damage.
文摘High-contrast is one of the main advantages in laser projection display, and the method of DCC (Dynamic Contrast Control) is the main way to increase the contrast. Generally, image pre-processing is necessary for eliminating noise and decreasing the over-highlight. In this paper, we proposed and actualized a method by following 3 steps: Firstly, the original image was analyzed statistically to get the scope of gray-scale distribution and average gray-scale;and then the image was divided into a number of sub-images. The sub-images whose pixels are higher than a certain threshold in both number and range, are applied image segmentation by certain growth rules. The sub-images satisfied with the growth rules are marked 1, and the rests are marked 0. Secondly, the sub-images are uniting. A sub-image has 3 relations between 8 sub-images around it: 1 and 1, 1 and 0, 0 and 0. The sub-images marked 1 are uniting together, and the sub-images marked 0 are uniting together. Without affecting the visual vision, all over-highlight pixels were reduced in a certain proportion. Lastly, based on the application of DCC, the whole image signals were enlarged and the brightness of light sources were reduced, so as to achieve the desired effect in contrast enhancement.
文摘The electric drive system characteristics of different projects for tracked vehicles are analyzed.For the two most typical projects,the parameters of power,torque and rotating speed and others of drive motor are figured out under the condition of satisfying adequate steering performance of the tracked vehicles.General opinions on the two projects are brought forward and conclusions are drawn.
文摘雷达在跟踪飞行目标时,常发生跟踪中断的现象。深度学习方法具有强大的学习能力,已被逐渐用于解决中断航迹关联问题。但已有基于深度学习的中断航迹关联方法未能充分考虑新老航迹特征之间的相似性,关联性能仍有待提升。因此提出一种基于深度时间对比的中断航迹关联算法(Track Segment Association based on Deep Temporal Contrasting,TSADTC),包括航迹特征提取模块、时间对比模块、航迹特征对比模块和分类器模块。航迹特征提取模块利用双向长短期记忆网络和编码器-解码器分别对新老航迹进行特征提取;时间对比模块分别使用一条航迹的特征预测另外一条航迹;航迹特征对比模块计算两条航迹的特征差别,并将此差别输入分类器中,以计算两条航迹关联的概率。算法将关联概率最大的航迹对作为关联航迹对。仿真实验表明,TSADTC算法能够有效提高中断航迹关联的正确关联率、错误关联率和航迹漏关联率性能。
