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Optical measurements based on practical methods for detecting time-wise morphing structures
摘要： Nowadays non-contact measurement methods have become widely used systems in several fields especially robotics, aerospace, architecture, and cultural heritage. Practical devices, taken from mass markets, are increasingly being used in scientific and engineering research fields thanks to their ability to combine good accuracy with to the low-cost and ready-to-use experimental setup. In the present paper, digital image analysis (based on digital camera devices) and three-dimensional scanning technique (based on Kinect I and Kinect II sensors) are compared to evaluate their performance in detecting a time-wise shape modification. Digital camera and Kinect sensors are used to the non-contact detection of a morphing blade able to modify its geometry according to airflow temperature variation. The comparison showed the capability of the digital image technique to provide quantitative information when a proper alignment is adopted, while the three-dimensional scanning process allows the continuous blade detection useful to quantify the shape modification. Two-dimensional and three-dimensional blade shape reconstruction processes are also discussed.
关键词： Reverse Engineering,Non-contact measurement,Point cloud,Kinect sensor,Optical method,Digital image analysis
更新于2025-09-23 15:23:52
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Human gait recognition based on deterministic learning and data stream of Microsoft Kinect
摘要： Gait is an important biometric technology for human identification at a distance. This study focuses on gait features obtained by Kinect and proposes a new model-based gait recognition method by combining deterministic learning theory and data stream of Microsoft Kinect. Deterministic learning theory is employed to capture the gait dynamics underlying Kinect-based gait parameters. Spatial-temporal gait features can be represented as the gait dynamics underlying the trajectories of spatial-temporal parameters, which can implicitly reflect the temporal changes of silhouette shape. Kinematic gait features can be represented as the gait dynamics underlying the trajectories of kinematic parameters, which can represent the temporal changes of body structure and dynamics. Both spatial-temporal and kinematic cues can be used separately for gait recognition using smallest error principle. They are fused on the decision level to improve the gait recognition performance. Additionally, we discuss how to eliminate the effect of view angle on the proposed method. Experimental results indicate that encouraging recognition accuracy can be achieved.
关键词： deterministic learning,Kinect-based gait features,Gait recognition,biometrics
更新于2025-09-23 15:23:52
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Comparing RGB-D Sensors for Close Range Outdoor Agricultural Phenotyping
摘要： Phenotyping is the task of measuring plant attributes for analyzing the current state of the plant. In agriculture, phenotyping can be used to make decisions concerning the management of crops, such as the watering policy, or whether to spray for a certain pest. Currently, large scale phenotyping in fields is typically done using manual labor, which is a costly, low throughput process. Researchers often advocate the use of automated systems for phenotyping, relying on the use of sensors for making measurements. The recent rise of low cost, yet reasonably accurate, RGB-D sensors has opened the way for using these sensors in field phenotyping applications. In this paper, we investigate the applicability of four different RGB-D sensors for this task. We conduct an outdoor experiment, measuring plant attribute in various distances and light conditions. Our results show that modern RGB-D sensors, in particular, the Intel D435 sensor, provides a viable tool for close range phenotyping tasks in fields.
关键词： INTEL D-435,RGB-D sensors,sensors in agriculture,INTEL SR300,empirical analysis,Microsoft Kinect,phenotyping,ORBBEC ASTRA S
更新于2025-09-23 15:22:29
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Training of Hand Rehabilitation Using Low Cost Exoskeleton and Vision-Based Game Interface
摘要： Motivating game-based training have the potential to improve therapy for people with neurological impairments. In recent years, the serious games have become extremely useful tools in rehabilitation field. They aim to stimulate the mobility of the body through an immersive experience that puts the user in interactive virtual environment. This paper is concerned about developing a customized augmented reality system for stroke rehabilitation. This will be done through integrating an interactive serious game interface with a hand exoskeleton device. This game-based rehabilitation system allows users to carry out physical rehabilitation therapies using a natural user interface based on Kinect’s skeletal tracking features and the electromyography (EMG) sensor. During game playing, the interactive user interface provides useful real-time feedback information such as the time required to grasp a desired dynamic virtual object, and the assigned score and thus the ability of the proposed system to provide a compensatory action regarding the dynamic behavior of the virtual target. The main goal of the developed virtual environment is to create positive influences on the rehabilitation process. Patient movement information and signals obtained from the developed exoskeleton device are used together to monitor the rehabilitation progress. The developed exoskeleton hand is a 3D printed low cost device suitable for grasping tasks that can be used even for domestic stroke patients. The developed exoskeleton device is not only a mechanical system able to perform the rehabilitation act but also it presents an effective tracking and traceability software solution. The EMG signals measured during hand motion are used to detect the intention of hand opening or closing which in turn will actuate the mechanical structure to accomplish the desired task. Parameters and results of patients’ exercises are stored and analyzed when needed to evaluate patients’ progress. The developed system is tested experimentally and it is able to restore the functions of the upper limb and mainly give patients more motivation to undergo the rehabilitation exercises.
关键词： Robotic exoskeleton,EMG control,Kinect sensor,3D printing,Stroke rehabilitation
更新于2025-09-23 15:22:29
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Multispectral imaging: Monitoring vulnerable people
摘要： This paper describes the development of a new healthcare monitoring system for vulnerable people which uses a visible image sensor and passive infrared sensors, in an unconventional manner, to monitor daily living activities. It based on a novel method, using chromatic methodology, to process spatially and temporally the incoming multispectral data from the visible and infrared parts of the spectrum, to overcome the impact of noisy environments, illumination changes and a dynamic background. An efficient chromatic descriptor is suggested to improve activity recognition of vulnerable people. The new monitoring system is robust to distortions associated with healthcare systems and its descriptor has an improved quality of description. System performance was evaluated using a series of experimental data, the results showing the efficacy of using both spatial and temporal domains of multispectral data to deal with events that disturb monitoring systems. The chromatic descriptor achieved a better performance in comparison to traditional methods when describing daily living activities.
关键词： Raspberry Pi,Laser image segmentation,Healthcare monitoring,Multispectral imaging,Microsoft Kinect
更新于2025-09-23 15:22:29
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Vision-based people detection using depth information for social robots
摘要： Robots are starting to be applied in areas which involve sharing space with humans. In particular, social robots and people will coexist closely because the former are intended to interact with the latter. In this context, it is crucial that robots are aware of the presence of people around them. Traditionally, people detection has been performed using a flow of two-dimensional images. However, in nature, animals’ sight perceives their surroundings using color and depth information. In this work, we present new people detectors that make use of the data provided by depth sensors and red-green-blue images to deal with the characteristics of human–robot interaction scenarios. These people detectors are based on previous works using two-dimensional images and existing people detectors from different areas. The disparity of the input and output data used by these types of algorithms usually complicates their integration into robot control architectures. We propose a common interface that can be used by any people detector, resulting in numerous advantages. Several people detectors using depth information and the common interface have been implemented and evaluated. The results show a great diversity among the different algorithms. Each one has a particular domain of use, which is reflected in the results. A clever combination of several algorithms appears as a promising solution to achieve a flexible, reliable people detector.
关键词： kinect,people detection,benchmarking,depth image processing,depth sensor,Social robotics,user detection,ROS
更新于2025-09-23 15:22:29
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Hybrid Plasmonic Waveguide based 3??3 Multimode Interferometer for Compact 120?° Optical Hybrid
摘要： The Kinect system is arguably the most popular 3-D camera technology currently on the market. Its application domain is vast and has been deployed in scenarios where accurate geometric measurements are needed. Regarding the PrimeSense technology, a limited amount of work has been devoted to calibrating the Kinect, especially the depth data. The Kinect is, however, inevitably prone to distortions, as independently confirmed by numerous users. An effective method for improving the quality of the Kinect system is by modeling the sensor’s systematic errors using bundle adjustment. In this paper, a method for modeling the intrinsic and extrinsic parameters of the infrared and colour cameras, and more importantly the distortions in the depth image, is presented. Through an integrated marker- and feature-based self-calibration, two Kinects were calibrated. A novel approach for modeling the depth systematic errors as a function of lens distortion and relative orientation parameters is shown to be effective. The results show improvements in geometric accuracy up to 53% compared with uncalibrated point clouds captured using the popular software RGBDemo. Systematic depth discontinuities were also reduced and in the check-plane analysis the noise of the Kinect point cloud was reduced by 17%.
关键词： 3D/stereo scene analysis,quality assurance,quantization,camera calibration,Kinect
更新于2025-09-23 15:21:01
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Hand-Held 3-D Reconstruction of Large-Scale Scene With Kinect Sensors Based on Surfel and Video Sequences
摘要： This letter presents a hand-held complex large-scale scene reconstruction method with Kinect sensors based on surfel and video sequences. The feature point method simultaneous localization and mapping (SLAM) is employed to estimate the pose of the camera, and then bundle adjustment by combining 2-D and 3-D feature points is used to optimize camera pose. Also, the surfel model is employed to construct deformation maps for the fusion and optimization of point clouds, and finally, an accurate precise 3-D map can be obtained. The main contribution of this letter is that: 1) by using the SLAM method to obtain camera pose as the initial value of optimization, the problem of insufficient memory and low efficiency of the structure form motion method can be well solved; 2) sparsely textured regions can be reconstructed better by using bundle adjustment by combining 2-D and 3-D feature points; and 3) dense 3-D reconstruction of large scenes can be achieved, and the reconstructed 3-D models are more elaborate. Finally, experimental results show that this proposed method can be applied to a variety of complex large-scale scenes, and can obtain accurate precise 3-D model. This presented 3-D reconstruction method can be widely used in the fields of human–computer interaction, consumer electronics, and virtual reality.
关键词： Kinect sensors,bundle adjustment,3-D reconstruction,surfel
更新于2025-09-23 15:21:01
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[ACM Press the 5th international Workshop - Berlin, Germany (2018.09.20-2018.09.21)] Proceedings of the 5th international Workshop on Sensor-based Activity Recognition and Interaction - iWOAR '18 - Respiration Rate Estimation with Depth Cameras
摘要： Depth cameras have been known to be capable of picking up the small changes in distance from users’ torsos, to estimate respiration rate. Several studies have shown that under certain conditions, the respiration rate from a non-mobile user facing the camera can be accurately estimated from parts of the depth data. It is however to date not clear, what factors might hinder the application of this technology in any setting, what areas of the torso need to be observed, and how readings are affected for persons at larger distances from the RGB-D camera. In this paper, we present a benchmark dataset that consists of the point cloud data from a depth camera, which monitors 7 volunteers at variable distances, for variable methods to pin-point the person’s torso, and at variable breathing rates. Our findings show that the respiration signal’s signal-to-noise ratio becomes debilitating as the distance to the person approaches 4 metres, and that bigger windows over the person’s chest work particularly well. The sampling rate of the depth camera was also found to impact the signal’s quality significantly.
关键词： ToF sensing,Kinect v2,respiratory rate,respiration measurement,non-contact measurement
更新于2025-09-23 15:21:01
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[Advances in Intelligent Systems and Computing] Information and Communication Technologies of Ecuador (TIC.EC) Volume 884 || Reliability and Validity of Postural Evaluations with Kinect v2 Sensor Ergonomic Evaluation System
摘要： Postural evaluations are becoming a priority in a world where occupational diseases derivatives from ergonomic situations are progressively common with serious consequences. This document proposes a semi-automatic ergonomic evaluation system with Kinect V2, which use the RULA method. It makes possible the discovery of conditions with postural risk and reduces errors in the estimating the evaluators’ measurements due to lack of experience, expertise and handling of measurement instruments. Reducing the ergonomic evaluation time, compared to the direct postural evaluation method at a low cost. In a controlled environment, 30 participants with homogeneous characteristics are evaluated their postural work, using a direct method (goniometer) and a non-invasive (Kinect V2) method, to then compared the statistically results using the coefficient of correlation named Cohen’s Kappa and vagueness type A. The final RULA scores issued by the direct method of postural evaluation and the proposed system are correlated. The uncertainty results established in the angular measurements on the arm, forearm, wrist, trunk and neck were respectively (±0.36°, ±0.22°, ±0.59°, ±0.27° and ±0.28°). A Cohen’s Kappa correlation coefficient of 0.953 was obtained, which means an almost perfect correlation between the evaluations of both systems.
关键词： Ergonomic evaluation,Non-invasive,Uncertainty,Kinect V2
更新于2025-09-23 15:21:01