63 research outputs found
Formulation and error analysis for a generalized image point correspondence algorithm
A Generalized Image Point Correspondence (GIPC) algorithm, which enables the determination of 3-D motion parameters of an object in a configuration where both the object and the camera are moving, is discussed. A detailed error analysis of this algorithm has been carried out. Furthermore, the algorithm was tested on both simulated and video-acquired data, and its accuracy was determined
Surface reconstruction of a blast plate using stereo vision
Includes bibliographical references.This thesis presents method for reconstructing and measuring the profile of a blast metal plate. Among the many methods in computer vision, stereo vision using two cameras is chosen as the range finding method in this thesis. This is because it is a non-contact method and hence eliminates the need to calibrate moving parts. A stereo-rig consists of two calibrated cameras and hence gives two view geometry. Stereoscopic reconstruction relies on epipolar geometry to constrain the relationship between the views. The 3-D point is then estimated using triangulation of the corresponding points from the two views. The blast plates that are reconstructed have highly reflective surfaces. This causes a problem due to specular reflection. This thesis further studies the reflective properties of the metal plate surface. Different methods of scanning the plate using the stereo-rig are investigated. The reconstructions obtained from these methods are analyzed for accuracy and consistency. Since low cost cameras are used in constructing the stereo-rig, the point cloud data obtained is further investigated for consistency by aligning different instances of the reconstruction. This is done using the Iterative Closest Programme (ICP) algorithm which tries to align two sets of data iteratively
Comprehensive review and application of particle image velocimetry
For a fluid dynamics experimental flow measurement technique, particle image velocimetry (PIV) provides significant advantages over other measurement techniques in its field. In contrast to temperature and pressure based probe measurements or other laser diagnostic techniques including laser Doppler velocimetry (LDV) and phase Doppler particle analysis (PDPA), PIV is unique due to its whole field measurement capability, non-intrusive nature, and ability to collect a vast amount of experimental data in a short time frame providing both quantitative and qualitative insight. These properties make PIV a desirable measurement technique for studies encompassing a broad range of fluid dynamics applications. However, as an optical measurement technique, PIV also requires a substantial technical understanding and application experience to acquire consistent, reliable results.
Both a technical understanding of particle image velocimetry and practical application experience are gained by applying a planar PIV system at Michigan Technological University’s Combustion Science Exploration Laboratory (CSEL) and Alternative Fuels Combustion Laboratory (AFCL). Here a PIV system was applied to non-reacting and reacting gaseous environments to make two component planar PIV as well as three component stereographic PIV flow field velocity measurements in conjunction with chemiluminescence imaging in the case of reacting flows.
This thesis outlines near surface flow field characteristics in a tumble strip lined channel, three component velocity profiles of non-reacting and reacting swirled flow in a swirl stabilized lean condition premixed/prevaporized-fuel model gas turbine combustor operating on methane at 5-7 kW, and two component planar PIV measurements characterizing the AFCL’s 1.1 liter closed combustion chamber under dual fan driven turbulent mixing flow
View generated database
This document represents the final report for the View Generated Database (VGD) project, NAS7-1066. It documents the work done on the project up to the point at which all project work was terminated due to lack of project funds. The VGD was to provide the capability to accurately represent any real-world object or scene as a computer model. Such models include both an accurate spatial/geometric representation of surfaces of the object or scene, as well as any surface detail present on the object. Applications of such models are numerous, including acquisition and maintenance of work models for tele-autonomous systems, generation of accurate 3-D geometric/photometric models for various 3-D vision systems, and graphical models for realistic rendering of 3-D scenes via computer graphics
Visual Servoing
The goal of this book is to introduce the visional application by excellent researchers in the world currently and offer the knowledge that can also be applied to another field widely. This book collects the main studies about machine vision currently in the world, and has a powerful persuasion in the applications employed in the machine vision. The contents, which demonstrate that the machine vision theory, are realized in different field. For the beginner, it is easy to understand the development in the vision servoing. For engineer, professor and researcher, they can study and learn the chapters, and then employ another application method
Triangulation methods in engineering measurement
Industrial surveying and photogrammetry are being
increasingly applied to the measurement of engineering
objects which have typical dimensions in the range 2-100
metres. Both techniques are examples of the principle of
triangulation. By applying photocrammetric concepts to
surveying methods and vice-versa, a general approach is
established which has a number of advantages. In
particular. alternative strategies for constructing and
analysing measurement networks are developed. These should
help to strengthen the geometry and simplify the analysis.
The primary results concern the use of non-levelled
theodolites, which have applications on board floating
objects, and three new suggestions for controlling and
computing relative orientations in photogrammetry. These
involve reciprocal observations with theodolites. the
photographing of linear scales defined by three target
points and employing cameras which have been levelled.
As a secondary result, some consideration Is given to
automation, and instrument design. It is suggested that
polarimetry could be successfully applied to improve the
transfer of orientation in confined situations, such as in
mining. In addition, the potential use of electronic
cameras as photo-theodolites is discussed
Technology 2003: The Fourth National Technology Transfer Conference and Exposition, volume 2
Proceedings from symposia of the Technology 2003 Conference and Exposition, Dec. 7-9, 1993, Anaheim, CA, are presented. Volume 2 features papers on artificial intelligence, CAD&E, computer hardware, computer software, information management, photonics, robotics, test and measurement, video and imaging, and virtual reality/simulation
Automated calibration of multi-sensor optical shape measurement system
A multi-sensor optical shape measurement system (SMS) based on the fringe
projection method and temporal phase unwrapping has recently been commercialised
as a result of its easy implementation, computer control using a spatial light
modulator, and fast full-field measurement. The main advantage of a multi-sensor
SMS is the ability to make measurements for 360° coverage without the requirement
for mounting the measured component on translation and/or rotation stages. However,
for greater acceptance in industry, issues relating to a user-friendly calibration of the
multi-sensor SMS in an industrial environment for presentation of the measured data
in a single coordinate system need to be addressed.
The calibration of multi-sensor SMSs typically requires a calibration artefact, which
consequently leads to significant user input for the processing of calibration data, in
order to obtain the respective sensor's optimal imaging geometry parameters. The
imaging geometry parameters provide a mapping from the acquired shape data to real
world Cartesian coordinates. However, the process of obtaining optimal sensor
imaging geometry parameters (which involves a nonlinear numerical optimization
process known as bundle adjustment), requires labelling regions within each point
cloud as belonging to known features of the calibration artefact. This thesis describes
an automated calibration procedure which ensures that calibration data is processed
through automated feature detection of the calibration artefact, artefact pose
estimation, automated control point selection, and finally bundle adjustment itself. [Continues.
- …