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Title
Proceedings, XXth congress

2004


EFFICIENT LINE MATCHING BY IMAGE SEQUENTIAL ANALYSIS
FOR URBAN AREA MODELLING
Y. Kunii*, H. Chikatsu
Tokyo Denki University, Department of Civil and Environmental Engineering,
Hatoyama, Saitama, 350-0394, Japan - (kunii, chikatsu)@g.dendai.ac.jp
Commission Youth Forum
KEY WORDS: Urban, Extraction, Sequences, Matching, Modelling, Visualization
ABSTRACT:
3D city modelling from airborne imagery includes mainly two parts: (1) image processing procedures and (2) 3D modelling for man-
made objects such as buildings, roads and other objects. Line extraction and sterco matching are usually utilized as an image
processing procedures. However, there are some issues for automatic man-made object modelling. In particular, spatial data
acquisition of buildings are important for reliable city modelling
With this objective, this paper focuses especially on efficient line matching method using optical flow and trifocal tensor.
Furthermore, line matching in general stereo matching methods were also investigated, and performance of the proposal line
matching method was compared with these general methods in this paper.
1. INTRODUCTION
Recently, efficient spatial data acquisition and visualization
have been receiving more attention from the view point of city
planning, city regeneration, telecommunications, environmental
and energy problems. Generally, in order to perform object
modelling using digital image, line or feature extraction and
stereo matching are performed, and many matching methods
such as area based matching, future based matching have been
proposed. In particular, line gives important information for
building extraction, and satisfied 3D results are depend on
rigorous line extraction and matching.
With this motive, the authors have been concentrating on
developing an efficient line matching procedure for man-made
object modelling using high vision imagery (Kunii and
Chikatsu, 2003). The line matching is comprised of line
extraction and line tracking, line extraction was performed by
Canny operator (Canny, 1986), and line matching was
performed using optical flow estimation and epipolar matching.
However, more efficient line matching is needed for automatic
3D modelling due to fragment or multiple lines during the line
matching procedure.
In these circumstances, this paper focuses on more efficient line
matching method using trifocal tensor (Beardsley, et al., 1996).
The trifocal tensor is geometric relation of 3 images, and useful
for point or line matching of multiple image. Therefore, the line
matching for the high vision imagery could be performed more
efficiently.
Furthermore, line matching by general stereo matching methods
were also investigated in this paper, and performance of the
proposal line matching method was compared with these
general methods.
Finally, 3D modelling for the urban area was performed by the
line information in this paper.

221
2. HIGH VISION IMAGERY
The high vision imagery in this paper was taken by high
definition television (HDTV) format. This paper reports the 3D
modelling method using the high vision imagery which
obtained from a helicopter at urban district of Kobe-city, Hyogo,
Japan. Table | shows the major components of the high vision
imagery, and Figure 1 shows the first frame imagery.
Table 1. Major components of the high vision’ imagery

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Figure 1. First frame imagery
3. LINE MATCHING BY OPTICAL FLOW
The line matching was performed by line extraction and line
tracking using optical flow. Detail procedures of the line
matching method are as follows.