requires corresponding graphics card, monitor capable of 3D
display and shutter glasses. So far, Morittai is tested only in
the configuration of NVIDIA 3D Vision.
Figurel. Hardware configuration using the NVIDIA 3D
Vision (using dual LCD)
2.2 Software function
The main function of Morittai is as follows.
(1) Morittai displays stereoscopic view of the aerial
photographs on the stereo window. Stereoscopic display
window uses the buffer for the right eye and left eye to
distinguish the Quad-buffer Stereo in OpenGL. In the stereo
window, two sub windows overview window and a window
that displays the zoomed in portion of the cursor location
are also displayed at the same time.
(2) The project file for Morittai stereo display contains aerial
triangulation elements or POS (Position and Orientation
System) of the aerial photographs and the information about
the respective left and right combination of aerial
photography.
(3) Morittai has the ability to input and edit vector data of 3D
Point, 3D Line and 3D Polygon and can be displayed as a
stereoscopic view.
(4) Forward intersection was used to measure the ground
coordinates from photo coordinates. Ground coordinates (X,
Y, Z) is calculated by employing the conditional condition
(eq. 1) between left and right photos. The possible error in
the confluence of the points due to the error in orientation
elements and external coordinate is optimized by using the
formula in eq.2.
A x'—xl Xo
Y |- AR y'- yt»
Zz el iz (1)
X xx xl
y [^R 7
Z 0
X x!
Y|=1/2W a - (b Z,a))4| Y Q
Z zi
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B8, 2012
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia
where c= focal length b = base line
À = scale ofimage R = rotation matrix
x, y = image coordinate
Xo, Yo, Zo = coordinates of projection center
X, Y, Z = object coordinate in ground coordinate
system
x ME
a z R'y-yla' 2 R'|yr-y;
vr —C
(5) A function that automatically generates stereo image for 3D
view by image matching has been incorporated. With this
additional function, the user with no or very less knowledge
in photogrammetry techniques can also use this system.
(6) A function that enables stereoscopic navigation seamlessly
between image pairs (as in Google Earth) is also integrated
for having a more realistic perspective of the real world
scenario.
(7) A sub window is also available that includes the map, or
images, or orthophoto etc of the complete project which will
provide the information about the users position with
respect to the complete project area.
(8) To calculate the timber volume, a function has been
incorporated that measures the timber volume directly from
the stereo image. A timber volume calculation is a function
of tree species, location, tree height and number of trees per
O.lha. A measurement procedure of timber volume
calculation is shown in Figure 2.
Figure 2. Calculation of timber volume
3. EXPERIMENTAL STUDY
3.1 Aerial digital imagery
For the aerial photography of the forested areas, UltraCamX
was used and the photograph was acquired with GSD of
approximately 30cm. Aerial survey was performed during
September to capture the greenness and fullness of the forest.
3.2 Site of experimental study
Aerial survey was performed in the Ogawa region Japan. The
study area is a mixed forest hilly region containing planted
conifer trees and deciduous trees primarily consisting oak,
chestnut, and Japanese cherry. The test field can also be visited
in the following web site.
http://
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