Proceedings Article | 6 August 2009
Yi Jin, Chao Zhai, Yonggang Gu
KEYWORDS: Optical fibers, Photogrammetry, Charge-coupled devices, CCD image sensors, CCD cameras, Speckle, Imaging systems, Cameras, Digital photography, Light sources
Digital close-range measurement technique is developed from the geodesy surveying and the photogrammetry
surveying, at present it is mainly applied to wide field detection with high relative accuracy, but its absolute accuracy is
not high, about one micron to one millimeter. In this paper we apply this technique to wide field multi-objects optical
fibers' space coordinates detection, a set of non-contact on-line detection system is designed and the accuracy of position
detection is less than 0.03mm in the field of 600mm×600mm, that means this system has high relative accuracy and high
absolute accuracy. In order to build this system, two aspects are mainly researched: CCD measurement error is the basis
of photogrammetry, in order to control measurement error, the influence to measurement error affected by speckle
recognition algorithm, the light source and camera space position is researched from experiments and theory. The result
shows some significant conclusions: the detection error of Gravity Method is about 0.03 pixel; The uniformity of light
source is important; The position detection of static goals through general photogrammetry can achieve high accuracy,
about several microns, but when objects are moving, F number, lamp-house, speckle status and imaging size will
probably cause additional measurement error, It is about a dozen microns to tens of microns. How to detect objects in
wide field of view is a critical problem in photogrammetry, for the normal single frame photo-field is about hundreds of
millimeter and the measuring field is several meters. In this paper, surface measuring through laser ranging device and
Triangle Intersection Method are used to obtain fibers' positions in wide field of view. And some key technologies are
adopted such as precise calibration of CCD camera, light rays adjustment method, subpixel image processing technology
and corresponding image points matching. Multi-objects can be detected simultaneously in the wide field of view
through theses technologies and the detection accuracy is increased. The experiments result shows that this system is
stable and reliable, and it has the potential in precision measurement, industry measurement and other application areas.
