nbul 2004
parts
ed parts
ding
3D MODELLING OF BUILDINGS BY USING LINE SENSOR
Tsukasa Hosomura
Dept. of Information and Arts, Tokyo Denki University, Ishizaka, Hatoyama, Hiki, Saitama, 350-0394, Japan
hosomura@ia.dendai.ac.jp
Commission V, WG V/2
KEY WORDS: Vision, Measurement, Modelling, Building, Camera, CCD, Instruments, Experimental
ABSTRACT:
Stereo method using two cameras can be got 3D information of all points in the scene. However, it is difficult to find out the
corresponding point in both scenes. In 3D modeling of the landscape, distance measurement of plural point on the object is sufficient
for modeling in most cases. It is possible to calculate the distance to the corresponding point, which has reflected on the scene obtained
from many directions on the horizontal surface. But, it is difficult to get many directions from stile camera. It was considered to use of
CCD line sensor for this situation. By putting the CCD line sensor on the mount, which rotates at the steady speed, and taking the
images of 360 degrees. It would be able to easily realize the 3D measurement of the object. In this study, such system was used
experimentally, and measurement accuracy was examined. The measurement was carried out using this system at university in Japan.
We took 15 target points around campus. Mean measuring error was about 15mm at the target about 100m far from cameras.
I. INTRODUCTION
Generally, 3D measurement of most equipment uses the
principle of the triangular measure. There are several methods
for example stereo method using the binoculus, spot projected
method, pattern projected method and moire topography, etc.
Stereo method is the passive method, other methods are active
method, which projects the light. Stereo method using two
cameras is called the binoculus stereoscopic vision. This method
can be got 3D information of all points in the scene. However, it
is difficult to find out the corresponding point in both scenes. In
3D modeling of the landscape, distance measurement of plural
point on the object is sufficient for modeling in most cases. It is
possible to calculate the distance to the corresponding point,
Which has reflected on the scene obtained from many directions
on the horizontal surface. But, it is difficult to get many
directions from stile camera. In order to get many scenes from
many directions, we used a vidco camera. This equipment is set
at plural positions (for example, camera A, camera B, camera C
and so on) on the identical circumference, and video scenes of
360 degree circumferences are obtained, and the images are
incorporated in personal computer by the frame rate ( 30
scene/second ) equal to the general television system. By putting
the video camera on the mount, which rotates at the steady speed,
and taking the images of 360 degrees. It would be able to easily
realize the 3D measurement of the object. By counting the scene
number of one camera (for example camera A), the angle from
the direction of other camera (for example camera B) to the
target marker can be calculated. Angle from the direction of
camera A to the same target marker can be calculated by using
the other camera B. As the result, distance from camera A to the
target marker can be found out. The distances from each
camera to the markers are calculated by using the above method.
But, this method needs huge number of image scenes. For
practical use, we need decrease the number of images. It was
considered to use of CCD line sensor for this situation. By
putting the CCD line ‘sensor on the mount instead of video
camera for above method. By using CCD line sensor, only one
image is sufficient for calculating the angle from a CCD line
sensor to the target maker. We can count line number instead of
scene number. It would be able to easily realize the 3D
measurement of the object. In this study, such system was used
experimentally, and measurement accuracy was examined.
2. OUTLINE OF THE SYSTEM
This system has been composed of 3 components. These are
CCD line sensor (CORE CCD camera CV-L103), servomotor
(FUN ELECTRIC, GYC101DC1-S) and decelerate gear system.