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光学三角法全视场自扫描测头的设计与研究 被引量:5
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作者 周会成 陈吉红 周济 《仪器仪表学报》 EI CAS CSCD 北大核心 2000年第5期493-496,507,共5页
本文基于光学三角法测量原理 ,设计了一种通过改变光平面与成像光轴夹角来实现对视场内被测零件表面扫描的视觉测头。通过紧凑的旋转镜片反射机构驱动光平面在物空间做扫描运动 ,将全视场自扫描功能封装在线结构光视觉测头内部 ,使扫描... 本文基于光学三角法测量原理 ,设计了一种通过改变光平面与成像光轴夹角来实现对视场内被测零件表面扫描的视觉测头。通过紧凑的旋转镜片反射机构驱动光平面在物空间做扫描运动 ,将全视场自扫描功能封装在线结构光视觉测头内部 ,使扫描成为线结构光视觉测头的一项内置功能。光平面定位精度实验以及尺寸测量的重复性精度实验均表明这种设计方案的可行性。这种自扫描测头对中、小尺寸零件三维尺寸的快速检测有重大的实用价值。 展开更多
关键词 光学三角法 视学检测 非接触测头 全视场扫描
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Contrast Detection Learning Improves Visual Contrast Sensitivity of Cat 被引量:6
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作者 华田苗 王振华 +1 位作者 徐金旺 刁建刚 《Zoological Research》 CAS CSCD 北大核心 2010年第2期155-162,共8页
Psychological studies on human subjects show that contrast detection learning promote learner's sensitivity to visual stimulus contrast. The underlying neural mechanisms remain unknown. In this study, three cats (Fe... Psychological studies on human subjects show that contrast detection learning promote learner's sensitivity to visual stimulus contrast. The underlying neural mechanisms remain unknown. In this study, three cats (Felis catus) were trained to perform monocularly a contrast detection task by two-altemative forced choice method. The perceptual ability of each cat improved remarkably with learning as indicated by a significantly increased contrast sensitivity to visual stimuli. The learning effect displayed an evident specificity to the eye employed for learning but could partially transfer to the naive eye, prompting the possibility that contrast detection learning might cause neural plasticity before and after the information from both eyes are merged in the visual pathway. Further, the contrast sensitivity improvement was evident basically around the spatial frequency (SF) used for learning, which suggested that contrast detection learning effect showed, to some extent, a SF specificity. This study indicates that cat exhibits a property of contrast detection learning similar to human subjects and can be used as an animal model for subsequent investigations on the neural correlates that mediate learning-induced contrast sensitivity improvement in humans. 展开更多
关键词 VISUAL Contrast detection LEARNING Contrast sensitivity CAT
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ADS-B Anomaly Data Detection Model Based on Deep Learning and Difference of Gaussian Approach 被引量:6
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作者 WANG Ershen SONG Yuanshang +5 位作者 XU Song GUO Jing HONG Chen QU Pingping PANG Tao ZHANG Jiantong 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2020年第4期550-561,共12页
Due to the influence of terrain structure,meteorological conditions and various factors,there are anomalous data in automatic dependent surveillance-broadcast(ADS-B)message.The ADS-B equipment can be used for position... Due to the influence of terrain structure,meteorological conditions and various factors,there are anomalous data in automatic dependent surveillance-broadcast(ADS-B)message.The ADS-B equipment can be used for positioning of general aviation aircraft.Aim to acquire the accurate position information of aircraft and detect anomaly data,the ADS-B anomaly data detection model based on deep learning and difference of Gaussian(DoG)approach is proposed.First,according to the characteristic of ADS-B data,the ADS-B position data are transformed into the coordinate system.And the origin of the coordinate system is set up as the take-off point.Then,based on the kinematic principle,the ADS-B anomaly data can be removed.Moreover,the details of the ADS-B position data can be got by the DoG approach.Finally,the long short-term memory(LSTM)neural network is used to optimize the recurrent neural network(RNN)with severe gradient reduction for processing ADS-B data.The position data of ADS-B are reconstructed by the sequence to sequence(seq2seq)model which is composed of LSTM neural network,and the reconstruction error is used to detect the anomalous data.Based on the real flight data of general aviation aircraft,the simulation results show that the anomaly data can be detected effectively by the proposed method of reconstructing ADS-B data with the seq2seq model,and its running time is reduced.Compared with the RNN,the accuracy of anomaly detection is increased by 2.7%.The performance of the proposed model is better than that of the traditional anomaly detection models. 展开更多
关键词 general aviation aircraft automatic dependent surveillance-broadcast(ADS-B) anomaly data detection deep learning difference of Gaussian(DoG) long short-term memory(LSTM)
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