Fig. 4 - The Rollei metric MR2 system. 
Self-calibration and data reduction 
A self-calibration technique has been used 
for the camera calibration procedure ( 
Torlegard, 1974,Fryer 1986, Kotowski, 1988). 
Using the "bundle adjustment" program of the 
MR2 software the camera is calibrated as part 
of the analytical reduction process. The 
camera calibration parameters ( parameters 
of interior orientation ) are recovered 
simultaneously with the known points x,y,z 
coordinates and the elements of exterior 
orientation in the least squares bundle 
adjustment. 
The physical self-calibration model contains 
the distorsion coefficients regarding the 
effects of medium ( water) and the interior 
orientation elements ( Xp, Yp co-ordinates of 
the principal point and C principal distance). 
Using non-metric cameras Nikonos the 
position of principal point has been measured 
on the photograms, while the focal lenght is 
introduced as the principal distance 
The bundle adjustment program was utilized 
introducing in input a very high variance ( 
100 mm. ) for the previous parameters of 
N 
Fig. 3 - Photographic equipment: from 
left to right th flash Nikonos 102 SB, 
the Nikonos IVA with 35 mm,the 
Nikonos Ill cameras with 15 and 28 mm, 
the flash Sea & Sea 200. 
  
orientation. 
internal 
points of the reference frame were collimated 
Contemporarly eight 
known 
were 
in the three photograms and their 
coordinates and relative distances 
introduced | with low variance ( 0.1 mm ). 
The omologous points of different 
photograms have been collimated in a 
monoscopic way with a pointer on a digitizer 
(fig. 4 }. 
Through a projective transformation 
bundle adjustment program permitted 
compute the correct internal parameters of 
the camera and fornished the orientation 
elements for the photograms also. 
The interior orientation elements Xp, Yp and 
C were recovered to a precision of c = +/- 0.04 
mm (for 28 e 35 mm lenses) and ¢ = +/- 0.03 
mm (for 15 mm lens). 
The nominal in air focal lenght of 15 mm for 
image distance of about 2 m. had a 
corresponding underwater computed principal 
distance of 19.8 mm while the 28 mm was 
39.2 mm and the 35 mm was 49.3 mm . 
the 
to