Autonomous underwater vehicles (AUVs) are regularly used for deep ocean applications. Commonly, the autonomous navigation task is carried out by a fusion between two sensors: the inertial navigation system and the Doppler velocity log (DVL). The DVL operates by transmitting four acoustic beams to the sea floor, and once reflected back, the AUV velocity vector can be estimated. However, in real-life scenarios, such as an uneven seabed, sea creatures blocking the DVL's view and, roll/pitch maneuvers, the acoustic beams' reflection is resulting in a scenario known as DVL outage. Consequently, a velocity update is not available to bind the inertial solution drift. To cope with such situations, in this paper, we leverage our BeamsNet framework and propose a Set-Transformer-based BeamsNet (ST-BeamsNet) that utilizes inertial data readings and previous DVL velocity measurements to regress the current AUV velocity in case of a complete DVL outage. The proposed approach was evaluated using data from experiments held in the Mediterranean Sea with the Snapir AUV and was compared to a moving average (MA) estimator. Our ST-BeamsNet estimated the AUV velocity vector with an 8.547% speed error, which is 26% better than the MA approach.
translated by 谷歌翻译
正常的胎儿脂肪组织(AT)发育对于围产期健康至关重要。在或简单地脂肪以脂质形式存储能量。营养不良可能导致过度或耗尽的肥胖。尽管以前的研究表明,AT和围产期结局的量之间存在相关性,但缺乏定量方法,对AT的产前评估受到限制。使用磁共振成像(MRI),可以从两个点Dixon图像中获得整个胎儿的3D脂肪和纯水图像,以在脂质定量时启用。本文是第一个提出一种基于Dixon MRI的胎儿脂肪分割的深度学习方法的方法。它优化了放射科医生的手动胎儿脂肪描述时间,以生成带注释的培训数据集。它由两个步骤组成:1)基于模型的半自动胎儿脂肪分割,由放射科医生进行了审查和纠正; 2)使用在所得的注释数据集中训练的DL网络的自动胎儿脂肪分割。培训了三个DL网络。与手动分割相比,我们显示出分割时间(3:38小时至<1小时)和观察者变异性(0.738至0.906)的显着改善。用3D残差U-NET,NN-UNET和SWIN-UNETR TRONSERTER网络对24个测试用例进行自动分割,平均骰子得分分别为0.863、0.787和0.856。这些结果比手动观察者的变异性更好,并且与自动成人和小儿脂肪分割相当。一名放射科医生审查并纠正了六个新的独立案例,并使用最佳性能网络进行了细分,导致骰子得分为0.961,校正时间显着减少了15:20分钟。使用这些新颖的分割方法和短暂的MRI获取时间,可以在临床和大型果园研究中量化全身皮下脂质的单个胎儿。
translated by 谷歌翻译