744 
Menci, Rinaudo 
to [gon] 
cp [gon] 
K [gon] 
Image 1 
0.000 
0.950 
-1.150 
Image 2 
0.001 
0.952 
-1.151 
Tab. 1: Relative orientation parameters of a stereopair acquired using CYCLOP 
The second series of tests refers to the computation of the coordinates of the calibrated points of the test fields and the distances be 
tween them. The first test field (see fig. 6) was recorded with a taking distance of 12 m and a base of 0.9 m (base/distance ratio 
greater than 1/13!). 
Considering a global precision of the photogrammetry of 10' ’ of the taking distance, the expected m.s.e. of the point coordinates is of 
1 cm. All the possible distances between the 30 points of the test fields were computed using both the coordinates from the CYCLOP 
acquisition and those from known coordinates of the control points. The absolute values of the discrepancies had a mean values of 13 
mm and standard deviation of 24 mm. 
The second test field (see fig. 7) was recorded with a taking distance of 1.3m and a base of 0.45 m (base/distance ratio equal to 1/3). 
All the distances between the nodes of the regular grid were measured on the CYCLOP images (d) and compared with the calibrated 
known distances (d’). 
Table 2 shows the results of this comparison. 
m(d-d’) = 
-0.01 mm 
a = 
± 0.06 mm 
m(|d-d’|) = 
0.15 mm 
a = 
± 0.04 mm 
Tab. 2: Mean values and standard deviation of the discrepancies of the second test field 
All the tests confirm the stability of the CYCLOP taking system: the absence of the y-parallaxes on the stereopair and final precisions 
that are typical of the calibrated digital camera that was used. 
4. THE SVCYCLOP SOFTWARE 
Apart from the taking system for the acquisition of stereopair, a plotting software was developed to simplify the approach for inexpe 
rienced users. The software, named SVCYCLOP, allows the measurement and direct 3D plotting of the recorded object; it offers all 
the facilities of a modern digital photogrammetric software, except the orientation programs. 
At the beginning the software only requires the names of the image files, the length of the base, an approximate value of the taking 
distance and the calibration data of the used camera-lens system (see fig. 8). 
SVCyclop Images Choosing 
Left 
vM odelli_cvclop\modelli_eyelop_4_7\D scJJ003. |pg 
Right I 
_J 
_J 
900 
6000 
The 3D coordinate recording can be performed by 
means of a traditional stereoscopic view or a sim 
ple monoscopic procedure. 
In particular, the monoscopic approach is 
equipped with a new collimation technique, named 
“stereofocusing” developed in order to simplify 
the correct choice of two homologous points. 
The left image is displayed on the monitor and the 
operator, using the mouse, can manage a pointer 
(usually a dot). A square window, centred on the 
pointer, shows the homologous part of the right 
image in transparency. 
By using the Z-control, the operator can move the 
right image along the epipolar line, until the x- 
parallax has been eliminated. 
This simple step is assisted, in real time, by an im 
age matching procedure; when the homologous points have been selected by the algorithm the border of the window changes from 
red to green. The operator can perform the collimation of homologous points as a focusing of a traditional reflex camera. 
Distance (base] between shots (mm): 
Distance from subject (mm): 
Camera Data File: 
OK 
Cancel 
3 
990 2723 
990 3608 
zj 
Fie. 8: SVCYCLOP - Input data 
Fig. 9: SVCYCLOP - Monoscopic 
collimation 
Fig. 10: SVCYCLOP - Different collimation steps of the homologous points: wrong col 
limation (red border), rough collimation (orange) and good collimation (green).