Objectives: To directly compare the quality of harmonic imaging (HI) and fundamental imaging (FI) in fetal echocardiography and to determine any differences in image quality between the two m0dalities. Methods : Fetal...Objectives: To directly compare the quality of harmonic imaging (HI) and fundamental imaging (FI) in fetal echocardiography and to determine any differences in image quality between the two m0dalities. Methods : Fetal echocardiograms were performed with the use of FI and HI in 58 fetuses, image quality and vi-sualization of left and right atria, left and right ventricles, mitral and tricuspid valves, aortic and pulmonary valves, left and right ventricular outflow tracts were evaluated and compared between FI and HI. Results :Mean HI scores were higher than mean FI scores (2.73±0.43 vs 2.16±0.69, P <0.001)for all the card-iovascular structures evaluated. Compared with FI, HI improved the image quality and visualization of fetal cardiac structures in subjects with both good (2.73±0.43 vs 2.88±0.32, P < 0.001) and suboptimal (1.65±0.41 vs 2.58±0.47, P < 0.001) echocardiographic windows. The interobserver correlation coefficient for the grading scores was 0.74 ( P < 0. 001 ) . Conclusions: harmonic imaging enhances and improves the im-age quality of fetal echocardiography ; and has important potential role in cardiac imaging in the fetus.展开更多
To address the problem of the low accuracy of transverse velocity field measurements for small targets in highresolution solar images,we proposed a novel velocity field measurement method for high-resolution solar ima...To address the problem of the low accuracy of transverse velocity field measurements for small targets in highresolution solar images,we proposed a novel velocity field measurement method for high-resolution solar images based on PWCNet.This method transforms the transverse velocity field measurements into an optical flow field prediction problem.We evaluated the performance of the proposed method using the Hαand TiO data sets obtained from New Vacuum Solar Telescope observations.The experimental results show that our method effectively predicts the optical flow of small targets in images compared with several typical machine-and deeplearning methods.On the Hαdata set,the proposed method improves the image structure similarity from 0.9182 to0.9587 and reduces the mean of residuals from 24.9931 to 15.2818;on the TiO data set,the proposed method improves the image structure similarity from 0.9289 to 0.9628 and reduces the mean of residuals from 25.9908 to17.0194.The optical flow predicted using the proposed method can provide accurate data for the atmospheric motion information of solar images.The code implementing the proposed method is available on https://github.com/lygmsy123/transverse-velocity-field-measurement.展开更多
为了提升信道状态信息(channel state information,CSI)指纹室内定位的性能,提出了一种改进MixNet的CSI图像指纹室内定位方法.在离线阶段,通过选择定位参考点(reference point,RP)处信号强度指示(received signal strength indication,R...为了提升信道状态信息(channel state information,CSI)指纹室内定位的性能,提出了一种改进MixNet的CSI图像指纹室内定位方法.在离线阶段,通过选择定位参考点(reference point,RP)处信号强度指示(received signal strength indication,RSSI)最强的3个接入点(access point,AP),提取其CSI数据并转换为图像;然后利用改进的MixNet模型对图像进行训练并保存模型.其中改进的MixNet引入了坐标注意力(coordinate attention,CA)和残差连接.首先,将MixNet-s中的SE(squeeze-and-excitation)注意力替换为CA,以增强网络的信息表示能力并更精确地获取CSI图像指纹特征.其次,根据MixNet-s模型的特点构建残差连接,以增强网络的表示能力并防止过拟合.最后,通过减小网络深度确保所有网络层得到充分训练;在线阶段,采集目标设备的CSI数据并转换为图像,输入已训练好的改进MixNet模型(命名为MixNet-CA);最后利用加权质心算法根据模型输出的概率值估计目标设备的最终位置.提出方法在室内环境中进行了验证,达到了0.3620 m的平均定位误差.展开更多
Duodenocaval fistula(DCF) is an uncommon but lethal clinical entity.The high mortality has been attributed to the difficulty of diagnosis before attempts at definitive therapy.In this case report,we describe a patient...Duodenocaval fistula(DCF) is an uncommon but lethal clinical entity.The high mortality has been attributed to the difficulty of diagnosis before attempts at definitive therapy.In this case report,we describe a patient with a series of computed tomography(CT) examinations over a 2-mo period in hospital.A low-density air bubble appeared in the inferior vena cava(IVC) on the second day in hospital and became clear on day 19,and gradually enlarged.Magnetic resonance imaging(MRI) also clearly demonstrated a high-signal enteric contrast medium or thrombus and signal-void air bubbles in the IVC.However,cavography did not show the filling defect.We suggest that noninvasive CT and MRI should be chosen as a first-line investigation,and IVC,including the surrounding structures,should be carefully reviewed on images if DCF is clinically considered.展开更多
Indoor Wi-Fi localization of mobile devices plays a more and more important role along with the rapid growth of location-based services and Wi-Fi mobile devices.In this paper,a new method of constructing the channel s...Indoor Wi-Fi localization of mobile devices plays a more and more important role along with the rapid growth of location-based services and Wi-Fi mobile devices.In this paper,a new method of constructing the channel state information(CSI)image is proposed to improve the localization accuracy.Compared with previous methods of constructing the CSI image,the new kind of CSI image proposed is able to contain more channel information such as the angle of arrival(AoA),the time of arrival(TOA)and the amplitude.We construct three gray images by using phase differences of different antennas and amplitudes of different subcarriers of one antenna,and then merge them to form one RGB image.The localization method has off-line stage and on-line stage.In the off-line stage,the composed three-channel RGB images at training locations are used to train a convolutional neural network(CNN)which has been proved to be efficient in image recognition.In the on-line stage,images at test locations are fed to the well-trained CNN model and the localization result is the weighted mean value with highest output values.The performance of the proposed method is verified with extensive experiments in the representative indoor environment.展开更多
文摘Objectives: To directly compare the quality of harmonic imaging (HI) and fundamental imaging (FI) in fetal echocardiography and to determine any differences in image quality between the two m0dalities. Methods : Fetal echocardiograms were performed with the use of FI and HI in 58 fetuses, image quality and vi-sualization of left and right atria, left and right ventricles, mitral and tricuspid valves, aortic and pulmonary valves, left and right ventricular outflow tracts were evaluated and compared between FI and HI. Results :Mean HI scores were higher than mean FI scores (2.73±0.43 vs 2.16±0.69, P <0.001)for all the card-iovascular structures evaluated. Compared with FI, HI improved the image quality and visualization of fetal cardiac structures in subjects with both good (2.73±0.43 vs 2.88±0.32, P < 0.001) and suboptimal (1.65±0.41 vs 2.58±0.47, P < 0.001) echocardiographic windows. The interobserver correlation coefficient for the grading scores was 0.74 ( P < 0. 001 ) . Conclusions: harmonic imaging enhances and improves the im-age quality of fetal echocardiography ; and has important potential role in cardiac imaging in the fetus.
基金supported by the National Natural Science Foundation of China under Grant Nos.12063002,12163004,and 12073077。
文摘To address the problem of the low accuracy of transverse velocity field measurements for small targets in highresolution solar images,we proposed a novel velocity field measurement method for high-resolution solar images based on PWCNet.This method transforms the transverse velocity field measurements into an optical flow field prediction problem.We evaluated the performance of the proposed method using the Hαand TiO data sets obtained from New Vacuum Solar Telescope observations.The experimental results show that our method effectively predicts the optical flow of small targets in images compared with several typical machine-and deeplearning methods.On the Hαdata set,the proposed method improves the image structure similarity from 0.9182 to0.9587 and reduces the mean of residuals from 24.9931 to 15.2818;on the TiO data set,the proposed method improves the image structure similarity from 0.9289 to 0.9628 and reduces the mean of residuals from 25.9908 to17.0194.The optical flow predicted using the proposed method can provide accurate data for the atmospheric motion information of solar images.The code implementing the proposed method is available on https://github.com/lygmsy123/transverse-velocity-field-measurement.
文摘为了提升信道状态信息(channel state information,CSI)指纹室内定位的性能,提出了一种改进MixNet的CSI图像指纹室内定位方法.在离线阶段,通过选择定位参考点(reference point,RP)处信号强度指示(received signal strength indication,RSSI)最强的3个接入点(access point,AP),提取其CSI数据并转换为图像;然后利用改进的MixNet模型对图像进行训练并保存模型.其中改进的MixNet引入了坐标注意力(coordinate attention,CA)和残差连接.首先,将MixNet-s中的SE(squeeze-and-excitation)注意力替换为CA,以增强网络的信息表示能力并更精确地获取CSI图像指纹特征.其次,根据MixNet-s模型的特点构建残差连接,以增强网络的表示能力并防止过拟合.最后,通过减小网络深度确保所有网络层得到充分训练;在线阶段,采集目标设备的CSI数据并转换为图像,输入已训练好的改进MixNet模型(命名为MixNet-CA);最后利用加权质心算法根据模型输出的概率值估计目标设备的最终位置.提出方法在室内环境中进行了验证,达到了0.3620 m的平均定位误差.
文摘Duodenocaval fistula(DCF) is an uncommon but lethal clinical entity.The high mortality has been attributed to the difficulty of diagnosis before attempts at definitive therapy.In this case report,we describe a patient with a series of computed tomography(CT) examinations over a 2-mo period in hospital.A low-density air bubble appeared in the inferior vena cava(IVC) on the second day in hospital and became clear on day 19,and gradually enlarged.Magnetic resonance imaging(MRI) also clearly demonstrated a high-signal enteric contrast medium or thrombus and signal-void air bubbles in the IVC.However,cavography did not show the filling defect.We suggest that noninvasive CT and MRI should be chosen as a first-line investigation,and IVC,including the surrounding structures,should be carefully reviewed on images if DCF is clinically considered.
基金supported by the National Natural Science Foundation of China (No.61631013)National Key Basic Research Program of China (973 Program) (No. 2013CB329002)National Major Project (NO. 2018ZX03001006003)
文摘Indoor Wi-Fi localization of mobile devices plays a more and more important role along with the rapid growth of location-based services and Wi-Fi mobile devices.In this paper,a new method of constructing the channel state information(CSI)image is proposed to improve the localization accuracy.Compared with previous methods of constructing the CSI image,the new kind of CSI image proposed is able to contain more channel information such as the angle of arrival(AoA),the time of arrival(TOA)and the amplitude.We construct three gray images by using phase differences of different antennas and amplitudes of different subcarriers of one antenna,and then merge them to form one RGB image.The localization method has off-line stage and on-line stage.In the off-line stage,the composed three-channel RGB images at training locations are used to train a convolutional neural network(CNN)which has been proved to be efficient in image recognition.In the on-line stage,images at test locations are fed to the well-trained CNN model and the localization result is the weighted mean value with highest output values.The performance of the proposed method is verified with extensive experiments in the representative indoor environment.
基金Acknowledgements This work was supported in part by the U.S. National Science Foundation （NSF） under grants CNS-1405670 and CN5-1658972. However, any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the NSE
