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- 实验方案
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Flicker Sensitivity in Normal Aging—Monocular Tests of Retinal Function at Photopic and Mesopic Light Levels
摘要： PURPOSE. Aging can affect many aspects of visual performance. In general, the effects become more significant in those older than 40 to 50 years, with increased intersubject variability and stronger dependence on ambient illumination. This study aimed to establish how healthy aging of the retina affects the detection of 15-Hz flicker under photopic and mesopic lighting. METHODS. We investigated 71 participants aged 20 to 75 years. Thresholds were measured for detection of 15-Hz flicker at the fovea (0°) and at an eccentricity of 4° in each of the four quadrants. The background luminance ranged from 0.6 to 60 cd/m2 and pupil size was measured continuously. Participants were excluded if they had signs/history of ocular disease, substantial interocular differences in flicker thresholds, or were unable to detect 100% flicker modulation in the high mesopic range. RESULTS. Mesopic and photopic flicker thresholds were used to calculate an index, the health of the retina index, to determine the limits of flicker sensitivity in healthy aging. Log flicker thresholds changed bilinearly with age; they remained stable until 40 to 50 years, with a linear decline with increasing age. This bilinear pattern of the change in flicker thresholds with age is consistent across photopic and mesopic light levels. CONCLUSIONS. The health of the retina index captures the lowest threshold, usually obtained under photopic conditions, as well as the loss of flicker sensitivity with decreasing light level. The established limits of healthy aging may benefit from future studies in patients with ocular hypertension and/or glaucoma that are known to experience loss of flicker sensitivity.
关键词： photopic,monocular vision,flicker,aging,mesopic
更新于2025-09-23 15:23:52
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Robust Landmark Detection and Position Measurement Based on Monocular Vision for Autonomous Aerial Refueling of UAVs
摘要： In this paper, a position measurement system, including drogue's landmark detection and position computation for autonomous aerial refueling of unmanned aerial vehicles, is proposed. A multitask parallel deep convolution neural network (MPDCNN) is designed to detect the landmarks of the drogue target. In MPDCNN, two parallel convolution networks are used, and a fusion mechanism is proposed to accomplish the effective fusion of the drogue's two salient parts' landmark detection. Considering the drogue target's geometric constraints, a position measurement method based on monocular vision is proposed. An effective fusion strategy, which fuses the measurement results of drogue's different parts, is proposed to achieve robust position measurement. The error of landmark detection with the proposed method is 3.9%, and it is obviously lower than the errors of other methods. Experimental results on the two KUKA robots platform verify the effectiveness and robustness of the proposed position measurement system for aerial refueling.
关键词： landmark detection,multitask parallel deep convolution neural network (MPDCNN),monocular vision,position measurement,Aerial refueling
更新于2025-09-23 15:22:29
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A geometric approach for kinematic identification of an industrial robot using a monocular camera
摘要： We propose a generic formulation to identify the kinematic parameters of an industrial robot using a geometric approach when no prior information about the robot’s kinematics is available. The joint axes were estimated using the singular value decomposition applied to the pose data of the robot’s end-effector. These data were obtained by actuating one joint of the robot at a time. The approach is first illustrated using the CAD model of the robot. Next, a simulation study was performed to decide on the number of data points and angular actuation required by a revolute joint to estimate the kinematic parameters. This was done considering the fact that there exist noise in the measurements from the sensors. In this paper, we used a monocular camera mounted on the end-effector of an industrial robot KUKA KR5 Arc as the measurement sensor. We used ArUco Marker maps instead of a single calibration grid to enhance the range of actuation for each joint that was otherwise restricted due to the Field of View of the camera. The robot’s kinematic parameters were then identified using the proposed approach. The identified parameters using the monocular camera were compared with those obtained using other measurement devices, namely, a total station and a laser tracker.
关键词： Kinematic identification,Singular value decomposition,Joint axes vector,Pose measurement,Monocular vision
更新于2025-09-23 15:22:29
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A monocular vision–based perception approach for unmanned aerial vehicle close proximity transmission tower inspection
摘要： Employing unmanned aerial vehicles to conduct close proximity inspection of transmission tower is becoming increasingly common. This article aims to solve the two key problems of close proximity navigation—localizing tower and simultaneously estimating the unmanned aerial vehicle positions. To this end, we propose a novel monocular vision–based environmental perception approach and implement it in a hierarchical embedded unmanned aerial vehicle system. The proposed framework comprises tower localization and an improved point–line-based simultaneous localization and mapping framework consisting of feature matching, frame tracking, local mapping, loop closure, and nonlinear optimization. To enhance frame association, the prominent line feature of tower is heuristically extracted and matched followed by the intersections of lines are processed as the point feature. Then, the bundle adjustment optimization leverages the intersections of lines and the point-to-line distance to improve the accuracy of unmanned aerial vehicle localization. For tower localization, a transmission tower data set is created and a concise deep learning-based neural network is designed to perform real-time and accurate tower detection. Then, it is in combination with a keyframe-based semi-dense mapping to locate the tower with a clear line-shaped structure in 3-D space. Additionally, two reasonable paths are planned for the refined inspection. In experiments, the whole unmanned aerial vehicle system developed on Robot Operating System framework is evaluated along the paths both in a synthetic scene and in a real-world inspection environment. The final results show that the accuracy of unmanned aerial vehicle localization is improved, and the tower reconstruction is fast and clear. Based on our approach, the safe and autonomous unmanned aerial vehicle close proximity inspection of transmission tower can be realized.
关键词： Close proximity inspection of transmission tower,monocular vision,UAV self-positioning,tower localization
更新于2025-09-23 15:22:29
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A coaxial alignment method for large aircraft component assembly using distributed monocular vision
摘要： The assembly of large component in out-field is an important part for the usage and maintenance of aircrafts, which is mostly manually accomplished at present, as the commonly used large-volume measurement systems are usually inapplicable. This paper aims to propose a novel coaxial alignment method for large aircraft component assembly using distributed monocular vision.
关键词： Posture evaluation,Particle swarm optimization (PSO),Aircraft assembly,Monocular vision,Coaxial alignment
更新于2025-09-23 15:21:01
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[IEEE 2018 International Conference on 3D Vision (3DV) - Verona (2018.9.5-2018.9.8)] 2018 International Conference on 3D Vision (3DV) - Multi-scale Direct Sparse Visual Odometry for Large-Scale Natural Environment
摘要： In this paper, we describe a multi-scale monocular direct sparse visual odometry (DSO) system to recover large-scale trajectories in unstructured natural environments in real time, while building a consistent metric map of the visited scenes. In contrast to the current state-of-the-art DSO system, the proposed method allows for more robust motion estimation and more accurate reconstruction in distant scenes by exploiting the characteristics of short- and long-range pixels, respectively. The long-range pixels, which are less sensitive to small camera translations, are used to initialize the camera rotation, so as to boost the tracking robustness in challenging natural environments. A multi-scale reconstruction framework is developed to recover short-range structure over successive frames, as well as the long-range structure over distant frames, hence allowing for a more consistent mapping precision. The reconstruction precision, the tracking accuracy, and the robustness of the proposed system are extensively evaluated with a publicly available vKITTI dataset, as well as the challenging Devon Island dataset, and Symphony Lake dataset. A detailed performance comparison between the proposed method and the state-of-the-art DSO system is presented.
关键词： multi-scale,large-scale natural environment,monocular vision,3D mapping,direct sparse visual odometry,real-time tracking
更新于2025-09-10 09:29:36
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No Useful Field Expansion with Full-field Prisms
摘要： Full-field prisms that fill the entire spectacle eye wire have been considered as field expansion devices for homonymous hemianopia (HH) and acquired monocular vision (AMV). Although the full-field prism is used for addressing binocular dysfunction and for prism adaptation training after brain injury as treatment for spatial hemineglect, we show that the full-field prism for field expansion does not effectively expand the visual field in either HH or AMV.
关键词： visual field,field expansion,full-field prisms,homonymous hemianopia,acquired monocular vision
更新于2025-09-10 09:29:36
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Field Expansion for Acquired Monocular Vision Using a Multiplexing Prism
摘要： SIGNIFICANCE: Acquired monocular vision (AMV) is a common visual field loss. Patients report mobility difficulties in walking due to collisions with objects or other pedestrians on the blind side. PURPOSE: The visual field of people with AMV extends more than 90° temporally on the side of the seeing eye but is restricted to approximately 55° nasally. We developed a novel field expansion device using a multiplexing prism (MxP) that superimposes the see-through and shifted views for true field expansion without apical scotoma. We present various designs of the device that enable customized fitting and improved cosmetics. METHODS: A partial MxP segment is attached (base-in) near the nose bridge. To avoid total internal reflection due to the high angle of incidence at nasal field end (55°), we fit the MxP with serrations facing the eye and tilt the prism base toward the nose. We calculated the width of the MxP (the apex location) needed to prevent apical scotoma and monocular diplopia. We also consider the effect of spectacle prescriptions on these settings. The results are verified perimetrically. RESULTS: We documented the effectivity of various prototype glasses designs with perimetric measurements. With the prototypes, all patients with AMV had field-of-view expansions up to 90° nasally without any loss of seeing field. CONCLUSIONS: The novel and properly mounted MxP in glasses has the potential for meaningful field-of-view expansion up to the size of normal binocular vision in cosmetically acceptable form.
关键词： prism glasses,visual field loss,field expansion,multiplexing prism,Acquired monocular vision
更新于2025-09-10 09:29:36
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[IEEE 2017 IEEE 7th Annual International Conference on CYBER Technology in Automation, Control, and Intelligent Systems (CYBER) - Honolulu, HI, USA (2017.7.31-2017.8.4)] 2017 IEEE 7th Annual International Conference on CYBER Technology in Automation, Control, and Intelligent Systems (CYBER) - Obstacle avoidance of aerial vehicle based on monocular vision
摘要： Collision-free autonomous navigation is extremely important for quadcopter and other flying robots. The implementation of autonomic moving capabilities can contribute significantly to their promotion and usage in fields such as goods delivering, aerial photos shooting, and monitoring. In order to realize the autonomous flight without crash, the obstacle avoidance problem demands a prompt solution. Also, with the concern of cost and endurance, using only single camera to perform this task would be a better choice for low-cost flying robots. Thus, this paper focuses on achieving quadcopter's collision avoidance in unknown stable (rarely changes, such as high sky or inner room) environment only by single camera. The algorithm proposed by this paper is composed of PTAM (Parallel Tracking and Mapping), DTAM (Dense Tracking and Mapping in Real-Time) algorithm and CNN (Convolutional Neural Network). PTAM is used to create the 3D map of the environment. DTAM is used to obtain the depth map of those image frames. And the CNN is used to train and get a model used for automatically avoidance. Finally, this algorithm is proved to be valid by an experiment.
关键词： Obstacle avoidance,CNN,quadcopter,PTAM,monocular vision,DTAM
更新于2025-09-09 09:28:46