Wendy Flores-Fuentes

Combined application of Power Spectrum Centroid and Support Vector Machines for measurement improvement in Optical Scanning Systems

In this paper Support Vector Machine (SVM) Regression was applied to predict measurements errors for Accuracy Enhancement in Optical Scanning Systems, for position detection in real life application for Structural Health Monitoring (SHM) by a novel method, based on the Power Spectrum Centroid Calculation in determining the energy center of an optoelectronic signal in order to obtain accuracy enhancement in optical scanning system measurements. In the development of an Optical Scanning System based on a 45^o - sloping surface cylindrical mirror and an incoherent light emitting source, surged a novel method in optoelectronic scanning, it has been found that in order to find the position of a light source and to reduce errors in position measurements, the best solution is taking the measurement in the energy centre of the signal generated by the Optical Scanning System. The Energy Signal Centre is found in the Power Spectrum Centroid and the SVM Regression Method is used as a digital rectified to increase measurement accuracy for Optical Scanning System.

Mobile robot vision system using continuous laser scanning for industrial application

Purpose The purpose of this paper is the presentation and research of a novel robot vision system, which uses laser dynamic triangulation, to determine three-dimensional (3D) coordinates of an observed object. The previously used physical operation principle of discontinuous scanning method is substituted by continuous method. Thereby applications become possible that were previously limited by this discretization. Design/methodology/approach The previously used prototype No. 2, which uses stepping motors to realize a discontinuous laser scan, was substituted by the new developed prototype No. 3, which contains servomotors, to achieve a continuous laser scan. The new prototype possesses only half the width and turns out to be significantly smaller and therefore lighter than the old one. Furthermore, no transmissions are used, which reduce the systematic error of laser positioning and increase the system reliability. Findings By using a continuous laser scan method instead of discontinuous laser scan method, dead zones in the laser scanner field can be eliminated. Thereby, also by changing the physical operation principle, the implementation of applications is allowed, which previously was limited by the fixed step size or by the object distance under observation. By using servomotors instead of stepping motors, also a significant reduced positioning time can be accomplished maintaining the relative positioning error less than 1 per cent. Originality/value The originality is based on the substitution of the physical operation principle of discontinuous by continuous laser scan. The previously used stepping motors discretized the laser scanner field and thereby produced dead zones, where 3D coordinates cannot be detected. These stepping motors were substituted by servomotors to revoke these disadvantages and provide a continuous laser scan, where dead zones in the field of view get eliminated and the step response of the laser scanner accelerated.

Energy Center Detection in Light Scanning Sensors for Structural Health Monitoring Accuracy Enhancement

This paper introduces a novel electronic circuit that has to be embedded in a photodiode sensor as an integrated circuit board for electronic signal processing that detects the energy center of an optical signal, which represents the most accurate position measurement from a light emitter source mounted on a structure (such as a building, a bridge, or a mine). The optical scanning sensor for structural health monitoring proposed is a flexible system that can operate with a coherent or incoherent light emitter source. It is conformable to any kind of structure surfaces and data storage budget thanks to the signal processing stage being embedded into the sensor and does not require additional software processing, which reduces the time and memory spacing requirements for information recording. The theoretical principle of operation, as well as the technological and experimental aspects of design, development, and validation is presented.

Scanning for light detection and Energy Centre Localization Methods assesment in vision systems for SHM

In this research, six Energy Centre Localization Methods are assessed by Wilcoxon Signed Rank Test. Due to SHM is an upcoming tendency of determining the integrity of structures and development of strategies to prevent undesirable damage, it is necessary to detect a light emitter mounted on the structure under monitoring and calculate the energy centre localization. After a short introduction to the energy centre localization methods, a machine learning technique was applied to predict measurement errors and adjust non-linear variation for measurement accuracy improvement. An Optical Scanning System was enhanced by measurement at the optical signal energy centre and error adjustment by SVM algorithm. The theoretical methods principles, experimental development and validation are presented.

Improve 3D laser scanner measurements accuracy using a FFBP neural network with Widrow-Hoff weight/bias learning function

Many laser scanners depend on their mechanical construction to guarantee their measurements accuracy, however, the current computational technologies allow us to improve these measurements by mathematical methods implemented in neural networks. In this article we are going to introduce the current laser scanner technologies, give a description of our 3D laser scanner and adjust their measurement error by a previously trained feed forward back propagation (FFBP) neural network with a Widrow-Hoff weight/bias learning function. A comparative analysis with other learning functions such as the Kohonen algorithm and gradient descendent with momentum algorithm is presented. Finally, computational simulations are conducted to verify the performance and method uncertainty in the proposed system.

Optical Cyber-Physical System Embedded on an FPGA for 3D Measurement in Structural Health Monitoring Tasks

Abstract This paper presents the description of a cyber-physical system embedded on an FPGA for 3D measurement in structural health monitoring tasks. The implementation technique and performance evaluation demonstrate the contribution of this paper to the mathematical fundamentals adaptation of an on-site rotatory scanning system to a cyber-physical system. In particular, it is described in detail the design of a virtual angle measurement soft sensing technique based on the information conversion of an optoelectronic signal provided by a rotatory scanning system through an FPGA. Behaving the FPGA as the sensor controller and the actuator in the scanning system. Using the measurement of angles through the proposed embedded system, it can be calculated the coordinates and displacement of specific indicators distributed over a structure under observation. Providing online data exchange from on-site measurement to a remote computational station for real-time or posteriorly data analysis.

Exact laser beam positioning for measurement of vegetation vitality

Purpose The purpose of this paper is to present a novel application for a newly developed Technical Vision System (TVS), which uses a laser scanner and dynamic triangulation, to determine the vitality of agriculture vegetation. This vision system, installed on an unmanned aerial vehicle, shall measure the reflected laser energy and thereby determine the normalized differenced vegetation index. Design/methodology/approach The newly developed TVS shall be installed on the front part of the unmanned aerial vehicle, to perform line-by-line scan in the vision system field-of-view. The TVS uses high-quality DC motors, instead of previously researched low-quality DC motors, to eliminate the existence of two mutually exclusive conditions, for exact positioning of a DC motor shaft. The use of high-quality DC motors reduces the positioning error after control. Findings Present paper emphasizes the exact laser beam positioning in the field-of-view of a TVS. By use of high-quality instead of low-quality DC motors, a significant reduced positioning time was achieved, maintaining the relative angular position error less than 1 per cent. Best results were achieved, by realizing a quasi-continuous control, using a high pulse-width modulated duty cycle resolution and a high execution frequency of the positioning algorithm. Originality/value The originality of present paper is represented by the novel application of the newly developed TVS in the field of agriculture. The vitality of vegetation shall be determined by measuring the reflected laser energy of a scanned agriculture zone. The paper’s main focus is on the exact laser beam positioning within the TVS field-of-view, using high-quality DC motors in closed-loop position control configuration.

Data transferring model determination in robotic group

This paper describes the basic idea of data transferring in the group of robots while they move in an area with a high density of obstacles with the goal of increasing their movement speed by creating and synchronizing an area map that is made by each robot separately. This paper provides a brief review of existing robotic swarm projects and definition of the problems in robot teamwork, shows pathfinding methods and their analysis, justifies our technical vision system choice and describes its method of obstacle detecting that is based on dynamic triangulation. According to some behavioristic models, using fuzzy logic, the method of leader changing was used. This knowledge helps with the choice of appropriate models of data transferring, makes their simulation and creates a proper network between the robots to avoid data loss. This idea of data transferring model in the group of robots is proposed.Justified technical vision system choice.Described technical vision system method of obstacle detecting.The mechanism of leader changing method based on fuzzy logic was used.

Machine vision supported by artificial intelligence

A performance evaluation of different artificial intelligence methods for machine vision using a rotatory mirror scanner is presented. This assessment concludes importance results, in order to properly select a method for the development of an precise optical scanning system for machine vision, with application in Structural Health Monitoring and Robot Navigation task.

Accuracy improvement in 3D laser scanner based on dynamic triangulation for autonomous navigation system

Autonomous navigation has been an important task in recent years to keep track of vehicles location, to provide safety and accuracy on its trajectory and to see their surroundings and predict if it is possible to travel across them. In this paper, a method to improve accuracy on laser vision systems based on dynamic triangulation for mobile robots is proposed. This laser vision system consists on a positioning laser, a scanning aperture and a fixed distance between them. The positioning laser points a laser beam over a surface and it is detected by the scanning aperture. The proposed method to improve accuracy on laser vision systems relies on the scanning aperture; current designs calculate the detection angle counting the pulses of a pulse train across a motor rotation. The disadvantage of this method is that the angular velocity of the motor may vary, resulting in an incorrect calculation of the angle of detection. In the proposed method, a new signal provided by an encoder is used to reduce the error generated by variations in angular velocity.