Vibration Monitoring with Video Cameras
C. K. Lee! and W. Faig?
Department of Ocean Engineering
Kunsan National University
68, Miryong, Kunsan, Chonbuk, 573-701, Korea
2 Department of Geodesy and Geomatics Engineering
University of New Brunswick
P. O. Box 4400, Fredericton, NB, Canada, E3B 5A3
Commission V, Working Group 3
KEY WORDS: Video Sequence Imagery, Direct Linear Transformation, Monitoring Dynamic Objects.
ABSTRACT
While close range photogrammetry has been widely applied for static deformation analysis, video cameras have many
characteristics that make them the sensors of choice for dynamic analysis of rapidly changing situations. They also
have limitations.
This paper explores the potential of a video system for monitoring dynamic objects. The system consists of two
camcorders, VCR, and PC with frame grabber. Basic characteristics of the video camera and frame grabber were
investigated in static and dynamic modes. Then, sequential images of a moving car were captured, and digitized in
1/15s intervals. The image coordinates of targets attached to the car were acquired by IDRISI, and the object
coordinates were derived based on DLT. This study suggests that home video cameras, PC, and photogrammetric
principles are promising tools for monitoring of moving objects and vibrations as well as other time dependent
situations.
KURZFASSUNG
Wie die Nahbereichsphotogrammetrie weitgehend für statische Deformationsmessungen eingesetzt wird, sind Video -
kameras für die Messung schnell sich ándernder Vorgánge geeignet.
In diesem Artikel wird die Anwendung eines Videosystems für die Messung beweglicher Objekte beschrieben. Das
System besteht aus zwei Camcorder, VCR und PC mit Framegrabber. Die Eigenschaften von Videokameras und
Framegrabber wurden für statische und dynamische Objekte untersucht. Anschliessend wurde eine Bildserie für ein
anfahrendes Auto aufgenommen und alle 1/15 Sekunden digitalisiert.
Die Bildkoordinaten der Zielmarken am Auto wurden üder IDRISI erhalten und mit Hilfe der Direkten
Lineartransformation(DLT) in Objektkoordinaten übertragen. Die vorliegende Untersuchung bestátigt, dass eine
einfache Videokamera, zusammen mit PC und photogrammetrischer Auswertung ein brauchbares System für die
Messung und Kontrolle bcweglicher Objekte und deren Schwingungsverhalten abgibt.
becoming increasingly popular in many fields of science
and industry, including photogrammetry, computer
It is well known that photogrammetry is ideally suited for Vision, robotics and biomechanics.
precision non-contact measurements for industrial The final objective of this research is to develop a fully
applications, particularly for objects which are difficult to automated real time photogrammetric system capable of
be precisely measured by a direct or contact method. Monitoring dynamic processes. In order to reach high
Most of the research in this field has been related to accuracy, the system requires sensors capable of taking
three dimensional positioning. When imaging changing Mages in short time intervals, data storage devices
situations in dynamic processes, the amount of data to be handling large amounts of data with high speed, and
manipulated with conventional analogue or analytical Mage processing tools that analyze the interesting
methods becomes prohibitively large. Recent features efficiently. Precise target location methods and
developments in solid state cameras, image processing positioning algorithms with suitable calibration techniques
techniques, and microprocessors have raised the area prerequisite for meeting the accuracy requirements.
interesting possibility of a fully automated In the past few years, some photogrammetrists have
photogrammetric system for close range applications. attempted to tackle the ^ above ^ mentioned
Compared to conventional cameras, it provides problems(Baltsavias & Stallmann, 1991, Laurin, 1993). :
sequential images based on TV standards. The use of The aim of this research is to gain experience on this
video cameras and frame grabbers for non-contact topic, to develop new algorithms and test existing ones,
measurement of physical dimensions, shape or motion is and to determine failures, their causes, and possible
1. INTRODUCTION
152
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B5. Vienna 1996
solutions. A
VCRs, fram
sequential ii
DLT, and
coordinates.
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this system
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an off-line
attached to
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As the video
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of recorded
