International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B4, 2012
XXII ISPRS Congress, 25 August - 01 September 2012, Melbourne, Australia
125
Test data 2
Area with high
buildings.
Size: 3000*3000
Test data 3
The normal area
Size: 4096*4096
Figure 5 three test data set.
The time cost of each processing step is showed in table 1.
Table 1 processing time
Processing step
Spending time (ms)
Datai
Data2
Data3
1. Wallis filter
672
1321
2321
2. feature extraction (Harris)
122
231
321
3. calculate left image vector
(10*10 points)
32
35
37
4. calculate right image vector
(all pixels)
753
1424
2531
5. find potential correspondences
12
12
11
6. remove error points by GHT
11
11
12
Total
1602
3034
5233
Table 2 processing time by SIFT
Spend time (ms)
Datai
Data2
Data3
Total
42304
93872
244387
(Download code form
http://www.cs.huji.ac.il/~ofirpele/SiftDist/codc,
Compiling by Microsoft Visual V++ 6.0 )
The matching results are showed in Figure 6.
2a 2b
3a 3b
Figure 6 Matching Result of The Method
As can be seen from the results, the image matching
algorithm based on the rotation vector field can indeed solve the
problem of image rotation , and the computing speed is much
faster than the traditional template matching algorithm in which
each pixel is involved in complex operations ( such as
convolution).
As we can see, the method can achieve good matching points
which can be used lately as the initial-value for the accurate
matching.
4. CONCLUSION
According to the above experiments, conclusions can be
drawn as following.
Firstly, the matching algorithm based on rotation vector field
is an optimized method which greatly reduces the computation
and improves the matching speed.
Secondly, the algorithm can get good results in regions with
rich features and few repeated features. And it’s not suitable for
regions that with poor feature or have a large number of
repeated features.
Thirdly, the accuracy of the matching points obtained by this
method is not that high. And these points can’t directly
participate in photogrammetry processing but can be used as the
initial-value for the accurate matching.
Our further research will focus on the scale-change problem
in the image matching which hasn’t been solved yet.
REFERENCES
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Herbert Bay,Tinne Tuvtellars and Luc Van Gool. 2006. SURF:
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Zhang Li,Zhang Zuxun,Zhang Jianqing. 1999.The Image
Matching Based on Wallis Filtering. Journal of Wuhan
Technical University of Surveying and Mapping, Vol, 24
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Sim D G, Kim H K, Oh D I. 2000. Translation, scale, and
rotation invariant texture descript or for texture based image
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Farhan Ullah, Shunichi Kaneko. 2004. Using orientation codes
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Yan Ke, Rahul Sukthankar. 2004. PCA2SIFT: A More
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