Camouflaged people are extremely expert in actively concealing themselves by effectively utilizing cover and the surrounding environment. Despite advancements in optical detection capabilities through imaging systems,...Camouflaged people are extremely expert in actively concealing themselves by effectively utilizing cover and the surrounding environment. Despite advancements in optical detection capabilities through imaging systems, including spectral, polarization, and infrared technologies, there is still a lack of effective real-time method for accurately detecting small-size and high-efficient camouflaged people in complex real-world scenes. Here, this study proposes a snapshot multispectral image-based camouflaged detection model, multispectral YOLO(MS-YOLO), which utilizes the SPD-Conv and Sim AM modules to effectively represent targets and suppress background interference by exploiting the spatial-spectral target information. Besides, the study constructs the first real-shot multispectral camouflaged people dataset(MSCPD), which encompasses diverse scenes, target scales, and attitudes. To minimize information redundancy, MS-YOLO selects an optimal subset of 12 bands with strong feature representation and minimal inter-band correlation as input. Through experiments on the MSCPD, MS-YOLO achieves a mean Average Precision of 94.31% and real-time detection at 65 frames per second, which confirms the effectiveness and efficiency of our method in detecting camouflaged people in various typical desert and forest scenes. Our approach offers valuable support to improve the perception capabilities of unmanned aerial vehicles in detecting enemy forces and rescuing personnel in battlefield.展开更多
目的探讨智能冠状动脉运动追踪平台Snapshot Freeze（SSF）在冠状动脉CT血管成像（CCTA）中的应用价值。方法连续选取61例患者,使用Discovery CT750 HD Freedom进行冠状动脉扫描,扫描后分别使用和不使用SSF重建,得到A、B两组图像;根据...目的探讨智能冠状动脉运动追踪平台Snapshot Freeze（SSF）在冠状动脉CT血管成像（CCTA）中的应用价值。方法连续选取61例患者,使用Discovery CT750 HD Freedom进行冠状动脉扫描,扫描后分别使用和不使用SSF重建,得到A、B两组图像;根据扫描实时心率将患者分为低心率组（心率≤70次/分,n=34）,中高心率组（心率71～80次/分,n=14）和高心率组（心率〉80次/分,n=13）。对比分析A、B组间和不同心率组间的图像质量差异。结果除左主干（S5）外,B组冠状动脉各节段图像质量评分均优于A组（P均〈0.05）;S5段剔除评分为5分者后,其余7例B组图像质量均优于A组（P=0.008）;未使用SSF重建时不可诊断的42个节段经用SSF重建后全部可用于诊断。未使用SSF重建的不同心率组间除S7、S9段外,其余各节段图像质量评分差异均有统计学意义（P均〈0.05）,图像质量随心率增加而下降;使用SSF重建后,不同心率组间各节段图像质量评分差异均无统计学意义（P均〉0.05）。未使用SSF重建的右冠状动脉中段（S2）在15段中评分最低（2.88±0.91）分,S3次之（3.65±1.32）分,且S2在低心率组亦有17例出现移动伪影影响其评估;使用SSF重建后,S2、S3移动伪影显著改善,评分分别提升至（4.32±0.59）分和（4.49±0.59）分,均满足诊断需求。结论 SSF能够有效地纠正高心率及心率波动导致的冠状动脉血管移动伪影,优化CCTA图像质量,尤其对右冠状动脉移动伪影有显著意义。展开更多
RAIM可用性预测系统是在飞机起飞前对飞机即将飞行的整个过程的机载GPS接收机的RAIM可用性进行预测,辅助空管和签派放行许可,是民航应用GPS导航的必要程序。SA(Selective Availability)取消前,SA是SPS(Standard Position Service)用户...RAIM可用性预测系统是在飞机起飞前对飞机即将飞行的整个过程的机载GPS接收机的RAIM可用性进行预测,辅助空管和签派放行许可,是民航应用GPS导航的必要程序。SA(Selective Availability)取消前,SA是SPS(Standard Position Service)用户的最大误差源,各颗卫星的UERE(User Equivalent Range Error)基本接近,在进行RAIM可用性预测时可认为所有可见卫星的UERE相同;SA取消后,电离层成为SPS用户的最大误差源,与用户到卫星的仰角紧密相关,相同UERE的假设将降低RAIM的可用性。文中针对此特性,基于传统的RAIM可用性预测方法,提出了加权RAIM可用性预测方法,并对权值的选择进行分析。计算机仿真结果表明,加权方法提高了RAIM可用性,缩短了RAIM不可用时段。算法已经应用于民航的RAIM预测系统,运行良好。展开更多
基金support by the National Natural Science Foundation of China (Grant No. 62005049)Natural Science Foundation of Fujian Province (Grant Nos. 2020J01451, 2022J05113)Education and Scientific Research Program for Young and Middleaged Teachers in Fujian Province (Grant No. JAT210035)。
文摘Camouflaged people are extremely expert in actively concealing themselves by effectively utilizing cover and the surrounding environment. Despite advancements in optical detection capabilities through imaging systems, including spectral, polarization, and infrared technologies, there is still a lack of effective real-time method for accurately detecting small-size and high-efficient camouflaged people in complex real-world scenes. Here, this study proposes a snapshot multispectral image-based camouflaged detection model, multispectral YOLO(MS-YOLO), which utilizes the SPD-Conv and Sim AM modules to effectively represent targets and suppress background interference by exploiting the spatial-spectral target information. Besides, the study constructs the first real-shot multispectral camouflaged people dataset(MSCPD), which encompasses diverse scenes, target scales, and attitudes. To minimize information redundancy, MS-YOLO selects an optimal subset of 12 bands with strong feature representation and minimal inter-band correlation as input. Through experiments on the MSCPD, MS-YOLO achieves a mean Average Precision of 94.31% and real-time detection at 65 frames per second, which confirms the effectiveness and efficiency of our method in detecting camouflaged people in various typical desert and forest scenes. Our approach offers valuable support to improve the perception capabilities of unmanned aerial vehicles in detecting enemy forces and rescuing personnel in battlefield.
文摘RAIM可用性预测系统是在飞机起飞前对飞机即将飞行的整个过程的机载GPS接收机的RAIM可用性进行预测,辅助空管和签派放行许可,是民航应用GPS导航的必要程序。SA(Selective Availability)取消前,SA是SPS(Standard Position Service)用户的最大误差源,各颗卫星的UERE(User Equivalent Range Error)基本接近,在进行RAIM可用性预测时可认为所有可见卫星的UERE相同;SA取消后,电离层成为SPS用户的最大误差源,与用户到卫星的仰角紧密相关,相同UERE的假设将降低RAIM的可用性。文中针对此特性,基于传统的RAIM可用性预测方法,提出了加权RAIM可用性预测方法,并对权值的选择进行分析。计算机仿真结果表明,加权方法提高了RAIM可用性,缩短了RAIM不可用时段。算法已经应用于民航的RAIM预测系统,运行良好。
