Oleg Sergiyenko

Surface recognition improvement in 3D medical laser scanner using Levenberg-Marquardt method

The 3D measurements of the human body surface or anatomical areas have gained importance in many medical applications. Three dimensional laser scanning systems can provide these measurements; however usually these scanners have non-linear variations in their measurement, and typically these variations depend on the position of the scanner with respect to the person. In this paper, the Levenberg-Marquardt method is used as a digital rectifier to adjust this non-linear variation and increases the measurement accuracy of our 3D Rotational Body Scanner. A comparative analysis with other methods such as Polak-Ribire and quasi-Newton method, and the overall system functioning is presented. Finally, computational experiments are conducted to verify the performance of the proposed system and its method uncertainty.

Spatial data acquisition by laser scanning for robot or SHM task

This paper presents through of the principle of laser triangulation a technique to acquisition data from an environment. The prototype can discover obstacles or objects in a unknown environment. Using a light source (laser) and very simple but efficient scanning unit is possible determinate distances and angles of any point on object in environment based in data acquisition by these elements. The most important parameters are: accuracy, functioning speed, range of action, and power requirements; the main characteristics is based in simplicity, versatility and economical accessibility. Fully automatic navigation and monitoring system is able to implement this prototype.

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.

Machine Vision: Approaches and Limitations

Machine vision in its common definition is a possibility of a machine (by sensing means and computer mathematic processing consecutively) to obtain an information about surrounding environment for further analytical treatment. According to this common definition we can unite in a general classification various, sometimes quite different by its principle, technical systems. These classification tables can be represented on the base of two different approaches: 1) practical causes (Soini, 2001) for necessity to “see surrounding environment”, and 2) technical principle and means using for this task solution. According to the common definition any complete Machine vision system combines two components: technical means (or hardware) and information processing mathematics and algorithm (or software). However, the various software analyses is not expedient in view of variety of mathematical methods and their object focused applications in each case (Mordohai & Medioni, 2006); and finally can’t give clearer problem understanding. We are now observing a rapid growth of 3D software and hardware capabilities for mainstream PCs, and 3D graphics accelerator boards with processing capabilities of roughly millions polygons per second are becoming commonplace (Petrov et al., 1998). At the same time, dynamic level-of-detail algorithms—built into standard 3D software packages— offer considerable acceleration of model viewing and progressive loading and transmission of 3D models. Despite the fast growth of computer 3D visualization capabilities, until recently data input technology has remained unchanged. So, in our research for better understanding what is Machine vision, what is its modern state, which practical and technical tasks it decide, and which objective limitations and open problems recently it have, we’ll based on the two mentioned above approaches. In a part of practical reasons, which caused for necessity to develop Machine (or computer) vision concept, can be mentioned: security problems in static/dynamic image analysis in perimeter/volume protection (motion/dangerous object detection); (Chellappa et al., 2005), (Itti & Baldi, 2005) analysis of short/long term deformation of important engineering structures (more commonly known as ‘structural health monitoring’ or SHM); (Athavale et al., 1990), (Allen et al., 2005), (Mallet et al., 2004), (Tyrsa et al., 2004), (Ohno et al., 2002), (Benedetti et al., 2004), (Slob & Hack, 2004), (Stewart & Tsakiri, 2002), (Liwen Dai et al., 2002) O pe n A cc es s D at ab as e w w w .ite ch on lin e. co m

3D laser scanning vision system for autonomous robot navigation

The presented Technical Vision System realizes the principle of dynamic triangulation. This technique is able to resolve in real time a triple task: to detect a presence of significant obstacle in a robots neighborhood; locate its position in a robots field-of-view; obtain in a short time a digital map of the obstacle visible surface with metrological accuracy of coordinates and adjustable step of discretization. Some aspects of theoretical backgrounds, technical design, optical principle, mathematical framework, signal processing, prototype design and experimentation are presented in this paper.

Resolution improvement of dynamic triangulation method for 3D vision system in robot navigation task

This paper presents a technical vision system designed to resolve multiple tasks which are fundamental for autonomous navigation. These tasks include detecting the presence of a significant obstacle for a mobile robot, locate its position in the mobile robots field of view and create a digital map of the obstacles visible surface with metrological accuracy. This technical vision system has been introduced and explained in other publications; therefore this paper focuses mostly on signal conditioning, processing and resolution increase for mobile robot navigation.

Remote Sensor for Spatial Measurements by Using Optical Scanning

In this paper, we propose a low-cost contact-free measurement system for both 3-D data acquisition and fast surface parameter registration by digitized points. Despite the fact that during the last decade several approaches for both contact-free measurement techniques aimed at carrying out object surface recognition and 3-D object recognition have been proposed, they often still require complex and expensive equipment. Therefore, alternative low cost solutions are in great demand. Here, two low-cost solutions to the above-mentioned problem are presented. These are two examples of practical applications of the novel passive optical scanning system presented in this paper.

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.

Automotive FDS Resolution Improvement by Using the Principle of Rational Approximation

In this paper, a novel method of frequency counting of signals coming from automotive sensors is presented. The present method helps to improve fast resolution of output parameters of typical automotive frequency-domain sensors (FDS). Controlling the electromechanical systems in todays cars is a task that requires a high processing speed. The method proposed here has been tested under computer experiments, and theoretical results have shown that it meets the requirements of speed of response and offset error of the parameters under measurement. Here, both a principle of rational approximation and its application to fast registration of frequency changes in the signal that is proportional to the physical parameter under measurement are shown. Finally, some experimental results are shown as well.