scholarly journals Advances in Optomechatronics: An Automated Tilt-Rotational 3D Scanner for High-Quality Reconstructions

Photonics ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 42 ◽  
Author(s):  
Silvia Logozzo ◽  
Maria Valigi ◽  
Gabriele Canella

3D vision systems are more and more required in a large variety of applications and mostly for mechanical and medical purposes. This paper presents the study and realization of a prototype of a structured light automated tilt-rotational 3D vision system for high-quality reconstructions of components of various sizes and in cases of freeform and complex surfaces. The main goal of this research work was to develop an instrument with the following main novelties: configurability for different object sizes, high precision and resolution levels and ability to automatically generate the mesh representing the full scanned objects without any intervention of the operator by means of a 2 degrees of freedom automated tilt-rotational mechanical positioning system. A detailed analysis of the instrument and the procedures and results of the performance tests are presented, together with the examination of possible strategies to obtain a better performance, especially by the calibration and the synchronization between the optical and the mechanical systems. As a result, the prototype and the performance parameters resulting from the experimental campaigns, are reported.

2013 ◽  
Vol 437 ◽  
pp. 471-474
Author(s):  
Zhuo Wu ◽  
Ke Yi Sun ◽  
Ming Song ◽  
Min Zheng

Shortages of skilled labor,extensive dangerous work,and technological advances are forcing rapid change in the construction industry, thus motivating construction automation,research and development of unmanned execution technologies for use to enhance safety has been undertaken.This paper presents an outline of research and development concerning automation of hydraulic excavator performed by applying a 3D vision system,3D information control system, a safety system, a 3D measurement system,and an operator interface communication system.As a result of the verification of the excavation motion suggest the technical possibility of achieving autonomous robotic excavation in moving toward construction automation.


Author(s):  
Juan C. Arellano-González ◽  
Hugo I. Medellín-Castillo ◽  
J. Antonio Cárdenas-Galindo

Human walking analysis is an important research area of biomedical engineering since it provides accurate information for medical rehabilitation procedures and design of rehabilitation equipment, medical diagnosis and orthopedics, pathological and aging evaluation, design of human prosthesis, and design of humanoid robots. In some applications, such as the design of prosthesis and rehabilitation systems in biomedical engineering, and equipment design and performance analysis in sports engineering, human walking reconstruction under several conditions is required in order to optimize the design. Human walking process is smooth and efficient but it varies from one person to another depending on age, height, gender, weight, health condition, and walking conditions. Most of the research work in the literature has been focused on the analysis of gait patterns of healthy and unhealthy people under normal walking conditions, and they use 2D reconstruction of human walking trajectories. The aim of this paper is to reconstruct and analyse human walking patterns of normal young adults under different gait conditions. A computer vision system to reconstruct 3D human walking trajectories is developed and presented in this paper. Several experiments with young adults walking under several conditions such as carrying a front load, carrying a lateral load, ascending, etc., are conducted. The results of these experiments have shown that human walking patterns vary according to the walking condition and therefore these variations should be considered in the design of prosthesis or rehabilitation systems.


2018 ◽  
Vol 7 (3.25) ◽  
pp. 1 ◽  
Author(s):  
Hameedah Sahib Hasan ◽  
Mohamed Hussein ◽  
Shaharil Mad Saad ◽  
Mohd Azuwan Mat Dzahir

Positioning system like global position system (GPS) and Local position system (LPS) have become very important in a large number of applications such as monitoring and tracking, etc. Because of the limitations of GPS in indoor environments due to the lack of line of sight (LoS), the use of LPS has become a true necessary to estimate user’s or object position with a good accuracy. In order to choose the best LPS system, a compromise between accuracy, precision, power consumption, coverage and cost should be taken into account. This paper introduces an overview of LPS performance parameters, current technologies, techniques and methods used by LPS. On the other hand, the comparison between LPS technologies and techniques used based on those technologies are also discussed. Furthermore, the LPS’s applications that have been done by previous researches such as human tracking, object tracking, animal tracking and automatic guide vehicle (AGV) tracking will be discussed. We believe this paper would catalyze further investigation by the researcher which is interested on the LPS field. 


2016 ◽  
Vol 852 ◽  
pp. 776-781
Author(s):  
R. Senthilnathan ◽  
R. Anand ◽  
Roshan Suresh Kumar ◽  
Shreyansh Keseri

Conventional design approach is being actively replaced by concurrent design approach in the context of interdisciplinary systems. The proposed research work intends to develop a single moving camera based stereo vision system for scene reconstruction with the intrinsic advantage of multi-directional fields of view. The conventional stereo vision setup uses two stationary passive cameras to capture images of a scene from different vantage points. The proposed system imparts varying mechanical degrees of freedom motion for both the object and the camera which aids in acquiring sequence of images which covers all the visible regions of the object of interest. This gives better detail of the scene under consideration as compared to the conventional two images based stereopsis. A mechatronics design approach has been presented which carefully integrates various elements of the system such as the mechanisms, actuators, sensors and the electronic controller. The paper clearly pin points the cues for the design of the mechanical system which are obtained from the requirements of the computer vision system. The relative pose between the camera and the scene is governed by three independent degrees of freedom namely rotation angle for the object, tilt and working distance for the camera. The selection of the aforementioned parameters is decided by the specifications such as field of view, size of the object and sensor and spatial resolution. The proposed design predicts the system to enjoy benefits of reduced cost and improved flexibility in general.


2020 ◽  
Author(s):  
Samuel C. Gill ◽  
David Mobley

<div>Sampling multiple binding modes of a ligand in a single molecular dynamics simulation is difficult. A given ligand may have many internal degrees of freedom, along with many different ways it might orient itself a binding site or across several binding sites, all of which might be separated by large energy barriers. We have developed a novel Monte Carlo move called Molecular Darting (MolDarting) to reversibly sample between predefined binding modes of a ligand. Here, we couple this with nonequilibrium candidate Monte Carlo (NCMC) to improve acceptance of moves.</div><div>We apply this technique to a simple dipeptide system, a ligand binding to T4 Lysozyme L99A, and ligand binding to HIV integrase in order to test this new method. We observe significant increases in acceptance compared to uniformly sampling the internal, and rotational/translational degrees of freedom in these systems.</div>


Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 791
Author(s):  
Sufei Zhang ◽  
Ying Guo

This paper introduces computer vision systems (CVSs), which provides a new method to measure gem colour, and compares CVS and colourimeter (CM) measurements of jadeite-jade colour in the CIELAB space. The feasibility of using CVS for jadeite-jade colour measurement was verified by an expert group test and a reasonable regression model in an experiment involving 111 samples covering almost all jadeite-jade colours. In the expert group test, more than 93.33% of CVS images are considered to have high similarities with real objects. Comparing L*, a*, b*, C*, h, and ∆E* (greater than 10) from CVS and CM tests indicate that significant visual differences exist between the measured colours. For a*, b*, and h, the R2 of the regression model for CVS and CM was 90.2% or more. CVS readings can be used to predict the colour value measured by CM, which means that CVS technology can become a practical tool to detect the colour of jadeite-jade.


IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 29449-29457
Author(s):  
Subhash Chandra ◽  
Arvind Yadav ◽  
Mohd Abdul Rahim Khan ◽  
Mukesh Pushkarna ◽  
Mohit Bajaj ◽  
...  

Author(s):  
M Sreekanth ◽  
R Sivakumar ◽  
M Sai Santosh Pavan Kumar ◽  
K Karunamurthy ◽  
MB Shyam Kumar ◽  
...  

This paper presents a detailed and objective review of regenerative flow turbomachines, namely pumps, blowers and compressors. Several aspects of turbomachines like design and operating parameters, working principle, flow behaviour, performance parameters and analytical and Computational Fluid Dynamics (CFD) related details have been reviewed and summarized. Experimental work has been put in perspective and the most useful results for optimized performance have been presented. Consolidated plots of specific speed-specific diameter have been plotted which can be helpful in the early stages of design. Industrial outlook involving details of suppliers from various parts of the world, their product description and applications too are included. Finally, future research work to be carried out to make these machines widespread is suggested. This review is targeted at designer engineers who would need quantitative data to work with.


Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 286
Author(s):  
Ashfaq Ali ◽  
Naveed Ullah ◽  
Asim Ahmad Riaz ◽  
Muhammad Zeeshan Zahir ◽  
Zuhaib Ali Khan ◽  
...  

Quartz Tuning Fork (QTF) based sensors are used for Scanning Probe Microscopes (SPM), in particular for near-field scanning optical microscopy. Highly sharp Tungsten (W) tips with larger cone angles and less tip diameter are critical for SPM instead of platinum and iridium (Pt/Ir) tips due to their high-quality factor, conductivity, mechanical stability, durability and production at low cost. Tungsten is chosen for its ease of electrochemical etching, yielding high-aspect ratio, sharp tips with tens of nanometer end diameters, while using simple etching circuits and basic electrolyte chemistry. Moreover, the resolution of the SPM images is observed to be associated with the cone angle of the SPM tip, therefore Atomic-Resolution Imaging is obtained with greater cone angles. Here, the goal is to chemically etch W to the smallest possible tip apex diameters. Tips with greater cone angles are produced by the custom etching procedures, which have proved superior in producing high quality tips. Though various methods are developed for the electrochemical etching of W wire, with a range of applications from scanning tunneling microscopy (SPM) to electron sources of scanning electron microscopes, but the basic chemical etching methods need to be optimized for reproducibility, controlling cone angle and tip sharpness that causes problems for the end users. In this research work, comprehensive experiments are carried out for the production of tips from 0.4 mm tungsten wire by three different electrochemical etching techniques, that is, Alternating Current (AC) etching, Meniscus etching and Direct Current (DC) etching. Consequently, sharp and high cone angle tips are obtained with required properties where the results of the W etching are analyzed, with optical microscope, and then with field emission scanning electron microscopy (FE-SEM). Similarly, effects of varying applied voltages and concentration of NaOH solution with comparison among the produced tips are investigated by measuring their cone angle and tip diameter. Moreover, oxidation and impurities, that is, removal of contamination and etching parameters are also studied in this research work. A method has been tested to minimize the oxidation on the surface and the tips were characterized with scanning electron microscope (SEM).


Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 391
Author(s):  
Luca Bigazzi ◽  
Stefano Gherardini ◽  
Giacomo Innocenti ◽  
Michele Basso

In this paper, solutions for precise maneuvering of an autonomous small (e.g., 350-class) Unmanned Aerial Vehicles (UAVs) are designed and implemented from smart modifications of non expensive mass market technologies. The considered class of vehicles suffers from light load, and, therefore, only a limited amount of sensors and computing devices can be installed on-board. Then, to make the prototype capable of moving autonomously along a fixed trajectory, a “cyber-pilot”, able on demand to replace the human operator, has been implemented on an embedded control board. This cyber-pilot overrides the commands thanks to a custom hardware signal mixer. The drone is able to localize itself in the environment without ground assistance by using a camera possibly mounted on a 3 Degrees Of Freedom (DOF) gimbal suspension. A computer vision system elaborates the video stream pointing out land markers with known absolute position and orientation. This information is fused with accelerations from a 6-DOF Inertial Measurement Unit (IMU) to generate a “virtual sensor” which provides refined estimates of the pose, the absolute position, the speed and the angular velocities of the drone. Due to the importance of this sensor, several fusion strategies have been investigated. The resulting data are, finally, fed to a control algorithm featuring a number of uncoupled digital PID controllers which work to bring to zero the displacement from the desired trajectory.


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