A COMPARATIVE EVALUATION OF THE POTENTIAL OF CLOSE RANGE
PHOTOGRAMMETRIC TECHNIQUE FOR THE 3D MEASUREMENT OF
THE BODY OF A NISSAN PATROL CAR
E.G. Parmehr, A. Azizi
Dept. of Geomatics and Surveying Engineering, Faculty of Engineering,
University of Tehran, 11365/4563 Tehran, Iran.
parmehr@ut.ac.ir, aazizı@ut.ac.ir
Commission V, WG VI/1
KEY WORDS: Close Range Photogrammetry, Industry, Metric Camera, Design, Calibration, Measurement, Accuracy.
ABSTRACT:
Close range photogrammetry as applied for the as-built and as designed comparisons in the car industry has attracted serious
attentions in recent years. This thesis reports in some details an off-line close range photogrammetric approach for the accurate
measurement of the body of a Nissan Patrol car. The photographs are taken by the Zeiss UMK 10/1318U metric camera. In the first
stage of the project, the body of the car is marked with the circular shape targets. The object coordinates of these targets were then
determined with respect to an arbitrary coordinate system using geodetic surveying technique. In the subsequent stage a network was
designed around the Nissan Patrol to be used for installing the cameras. The image coordinates of the target points were then
measured by the SD2000 analytical plotter. The object coordinates of these points were calculated using collinearity condition
equations combined with various self calibration strategies proposed by: Brown 1975, Brown 1976, Ebner 1976, Moniwa 1977 and
El-Hakim 1977. The discrepancies between the coordinates of the points generated by the photogrammetric method and the
coordinates of the same points produced by the geodetic approach, is taken as the accuracy criteria. The best results obtained for
check points are 0.21 mm (rmse).
1. INTRODUCTION camera documentation. The full camera specification is given in
Table 1.
In recent years close range photogrammetry has demonstrated
its capability as a powerful technique for the metric acquisition Lens Lamegon 8/100 B
of industrial objects. The close range photogrammetric method Focal length 99 mm
reigns supreme as regards the ease of data acquisition, Focusine range 1.4 m to infinity
t € S .
instantaneous data capture and cost effectiveness as compared
to alternative solutions. As far as the accuracy of the extracted
metric information is concerned, two solutions are common.
Effective frame size 120 x 166 mm
Camera weight with | 20 kg
accessories
The first approach employs a non metric camera and ET : : : :
: E p. y th = e d : | Effective size of the | 79 and 61 degrees for the
compensates the accuracy loss with appropriate mathematica : ; : n ER
Beas: y Pprop à angular view horizontal and vertical direction
models. The second method on the other hand utilizes a
combination of hardware and software solutions by utilizing a
metric camera. In this project the second solution is adopted for
the measurement of distinct points on a Patrol car using a Zeiss
UMK metric camera. Since the internal geometry of this camera
is known with sufficient accuracy, no pre-calibration is
required. This paper gives a brief outline of the procedures
involved in the 3D object coordinates extraction of series of
signalized points installed on a Patrol car. The accuracy results
are also reported.
Table 1. UMK 10/1318U camera specifications
2.2 Film characteristics
To perform the image acquisition with highest possible
resolution, a slow speed film with the finest granularity
available in the market was purchased. Since the object being
photographed was completely stationary, no motion blur was
introduced into the acquired image. Figure 1 and 2 demonstrate
the resolution of the selected film as compared with a faster
film.
2. DATA AQUISITION
The data acquisition stage is briefly outlined in the sub-sections
that follow.
2.1 UMK 10/1318U metric camera
po :
Image acquisition is conducted with a Zeiss UMK 10/1318 2
metric camera. This camera has a stable internal geometry with su an
a minimum of lens distortion. The internal geometry is
accurately determined by the manufacturer and reported in the
Figure 2. Image of a portion of an object taken by fast film
Internation
2.3 Signaliz
To determi
more easily
with differc
were then 1
these target
target cente
result indic:
as regards t
that were r«
indicated be
To determi
relation is a
D ud
min
where d 1s 1
object distai
view to th
diameters o
places on tl
entire body
interval bet
Figu
2.4 Geodeti
The 3D obje
geodetic net
1000 total st
0.1 mm and
respectively.