CIPA 2003 XIX th International Symposium, 30 September - 04 October, 2003, Antalya, Turkey 
3. THE ACQUISITION MODES 
The DM is the case when the old map can be safely scanned 
with this mode. Depending on the size of the map, the sup 
porting material and on the sensitivity of the drawing or print 
ing, several types of high-resolution scanners can be used diffe 
ring each time in: 
■ Format. 
■ Placement of the map and the type of the earner 
motion; Mechanics of the moving sensor. 
■ Resolution; Sensor properties. 
■ Lighting type and intensity. 
■ Cost. 
■ 
In cases DM is not applicable, the photogrammetry-prone indi 
rect mode (IM) has to be implemented. Here, proper digital and 
/ or analogue photo cameras can be used, IM-dc and/or IM-ac 
respectively, the latter requiring a further step, the a-posteriori 
external scanning (IM-ac/d). 
In each mode, dfs of the old map original are acquired using the 
following hardware: 
■ DM: Hard-copy scanners. 
■ IM: 
- IM-dc; digital cameras. 
- IM-ac; analogue cameras, provide film sli 
des and film diapositives which can be then 
digitised using film scanners, IM-ac/d. 
In this way, three main types of dfs of the same old map can be 
generated by: 
■ The DM, 
■ the IM-dc and the 
■ IM-ac/d. 
Attention should be focused on the results obtained from the 
use of different types of dfs-generating scanning devices in the 
DM case, from the technical specifications of the digital and/or 
analogue cameras in the IM case and from the use of different 
types of dfs-generating scanning devices in the IM-ac/d sub 
case. 
4. THE INDIRECT MODE 
The nature of the old map implies that in the most of the cases 
it is proper to use the IM image capturing procedure. In this ca 
se, both IM-dc and IM-ac lead to the very need of applying 
photogrammetric methods and techniques. The IM-ac/d variant 
introduces some additional issues related to the scanning pro 
cess. Due to the state of the art in digital photography, the IM- 
dc case needs rather high cost investment and it still requires 
skills, which are not yet the common case in the every-day life 
of professional photography. In this context IM-ac seems to be 
the prosaic case and the indeed main stream in old map 
documentation. The generation of the relevant dfs is an a- 
posteriori process associated to the IM-ac/d. 
It is needless to say that not only the IM procedures but also the 
DM counterpart, introduce a variety of errors and image altera 
tions that need to be first identified and then removed before 
final expert analyses are performed on the “restored” map ima 
ge. A typical example is the well-known image distortions due 
to the inherent in any photo acquisition procedure central pro 
jection. These distortions are present in any map image derived 
by either IM-dc or IM-ac together with other errors, which 
should be removed in order to obtain an ortho projection of the 
map’s image, which can be easily done using off the shelf recti 
fication software applications.- 
V 
Results 
Figure 1. The proposed flowchart for old maps scanning and 
unified photo/carto digital processing.