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USABILITY AND POTENTIAL USE OF THE HIGH RESOLUTION DIGITAL
CAMERA IN THE DETERMINATION OF 3D DIGITAL MODEL
L. Fregonese
DIIAR - Department of Hydraulic, Environmental, Street Infrastructures and
Survey Engineering Survey Division - Polytechnic of Milan - ITALY
Laboratory of “Survey, Digital Mapping and GIS” - P.za Leonardo Da Vinci 32 - 20133 Milano - ITALY
tel. +39 2 2399 6533 fax +39 2 2399 6550
luigi.fregonese@polimi.it cristiana.achille@polimi.it
CIPA 2003 XIX International Symposium
“New perspectives to save cultural heritage”
Antalya - Turkey, 30 September - 4 October 2003
KEY WORDS: Cultural heritage, Photogrammetry , Calibration, Modelling, Orthophoto
ABSTRACT:
The research describes the study realized by the Department of Hydraulic, Environmental, Street Infrastructures and Survey
Engineering - Survey Division of Polytechnic of Milan, in order to examine the potential use of the high resolution digital camera in
the determination of 3D digital model. The aim of this work was to develop an method to estimate and compared the parameters of
inner orientation and geometric distortions, i.e. radial, tangential. The method has been implemented in such a way to allow a
calibration camera and compared the result whit the builder metric calibration certificate. The digital metric camera used in this work
is the Rolleiflex 6008 integral with fixed mounted digital back Sensor and chip with 4080 x 4076 pixel (36.72 x 36.684mm).
In the second step it has been built up the application and experimental phase: particularly, the realization of a 3D digital orthophoto
at scale 1:1 of the mosaic surface of the S. Marcus Basilica in Venice; the DSM obtained for auto-correlation with software of digital
photogrammetry is compared with the levelling control point. 1
1. INTRODUCTION
1.1. Method to estimate the inner orientation
In order to extract from theses digital images careful 3D
information today is possible whit the high resolution camera.
The camera calibration typical issue in photogrammetry
applications where the dimensional measurement are required.
The aim of this work was to develop an method to estimate and
compared the parameters of inner orientation and geometric
distortions (i.e. radial) and compared the result whit the builder
metric calibration certificate: the digital metric camera used is
the Rolleiflex 6008 integral with fixed mounted digital back
Sensor (Phase One) with 4080 x 4076 pixel (36.72 x
36.684mm).
The main aspect of camera calibration is the estimate of the
internal parameters and the correction of geometrical lens
distortions.
In order to solve this calibration, the research adopting a three-
steps method:
1. the first step define the initial value of calibration and
external orientation of an image without lens distortions;
2. with the initial parameter we improve the estimate of all
camera parameters (internal orientation and only radial
distortions;
3. Use the estimate value in step 2 for T.A. block adjustment.
This approach can be useful when the builder metric calibration
certificate is not present or when is required a comparison.
1.2. The method of calibration
Lens distortion is the aberration most relevant to
photogrammetry. While other aberrations mainly affect image
quality, lens distortion directly affects the metric accuracy of the
image and must be corrected in photogrammetry .
Radial distortion is the radial displacement of an imaged point
from its theoretically correct position or, equivalently, a change
in the angle between a ray and the optical axis.
In order to define the distortion the parameters of the internal
orientation of the camera it is rerun by means to self-calibration,
in which the distorsion and camera parameters are included as
part of the bundle adjustment solution.
The digital camera used in this research is Rollei DB44metric
with optical lens 40mm. The camera allow the following point:
saving of images Loss-free or RAW-format, up to 48 bit
colour depth, 32 MB per image;
lenses, interchangeable metric lenses PQ (fastest shutter
speed: 1/500 sec) between 40mm and 350 m,
interchangeable metric lenses PQS (fastest shutter speed:
1/500 sec) between 50 mm and 500 mm.
metric calibration for each lens;
pixel in X (4.080 ), pixel in Y 4.076 and pixel size 9pm.
The calibration certificate for the camera used in this work
supply:
