5. CONCLUSIONS
Applying the matching and estimation method of CV in MMS,
broaden the research area of photogrammetry, it can be
concluded from the experiment that have conducted:
(1) Compare to traditional photogrammetry, the CV RO based
on matrix have a more concise form, and is easier to
programming, besides, this method suits for general heading
angle.
(2) Applying the excellent extraction and matching algorithm
SIFT and RANSAC robust estimation method in vehicle-based
sequential images processing, the experiments show this
method has high stability.
(3) Now the precision of RO based on CV is limited, but the
precision is relative high.
The quality of RO mainly relates to the quality of the images
and matching algorithm. With the development of computer
hardware and the popularize of parallel arithmetic, the time of
extraction and matching will be shorter, this method is
expected to be used in indoor visual navigation or provide
initial RO value in position field, which has little require on
time and precision. Moreover, after rigorous calibration, the
quality can be greatly improved.
RO is a fundamental question in photogrammetry and CV. RO
based on vision is a method with low cost and relatively high
reliability, so in traditional photogrammetry and CV, RO
based on vision privilege over other method. But, the precision
of the result by this method is not very high, and there are
many factors that affect the result by vision method, including
the quality of the image, the precision of camera calibration
parameters, the quality of image matching, data processing
and its optimization etc. Under the condition that the quality
of the image is unchangeable, the quality of the result can be
improved purely by improving the data processing method and
algorithm, but the extent is limited. For example, the
homologous points acquired by SIFT were not identified by
correlation coefficient, the precision cannot be guaranteed. It
is hard to guarantee large overlap (the overlap over 60%) (LI
Jinwen and ZHAN Zongqian,2010), in order to meet the
demand of multiple view matching and bundle adjustment.
Besides, there are many uncertain factors in environment:
these are important factors that influence the RO based on
vision, with the improvement of relative technology, the
quality of RO will be improved.
Acknowledgements
I would like to thank Beijing maggroup group for the vehicle
based sequential image data of Landmark MMS. Also I
appreciate the enthusiastic help of Cheng Xu, manager of the
company, Doc.Wang Yanzheng and Liu Hua, postgraduate of
School of Geodesy and Geomatics, Wuhan University.
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