Full text: New perspectives to save cultural heritage

CIPA 2003 XIX th International Symposium, 30 September - 04 October, 2003, Antalya, Turkey 
2.1 Operator software for IMAGER 
The operator software is designed for the 
scanning in the field. The software is very easy 
to handle by using predefined settings for the 
scanning. The software enables the operator to 
select between five predefined buttons to set the 
application specific scanner parameters. By 
selecting the low function - enabling more than 
12 million points to be scanned in less than 20s, 
a preview of the area to be scanned in detail can 
be measured and afterwards selected to be 
rescanned using a higher point density. 
The Operator integrates the software package 
LF Viewer for visualisation purposes and online 
data measurements by means of a so called 
“virtual surveying” functionality. 
2.2 LF Viewer 
Directly after the measuring, the first results can 
be seen on the computer. The surveyed area is 
shown on the screen as a grey-coded reflectance 
image. It is similar to a black-and-white photo 
and therefore does not require much experience 
to interpret. 
After each scan, the surveyor can see directly in 
the reflectance image (Fig. 3) the objects which 
have been captured. When objects are hidden 
by other objects, it may be necessary to scan 
this region from another point of view. 
Figure 3: Reflectance Image 
Another way of checking the scan is with the 
grey-coded range image. It is the compli 
mentary image to Fig. 3, viewing the same area: 
but range is displayed rather than reflectance. In 
the range image, every range has its own grey 
level; the greater the distance to an object is, the 
lighter the object is represented. Objects which 
are near by the sensor are almost black. As this 
is not natural to the human eye, some 
experience is needed to get useful information 
from this view. The range image is important 
for the control of the ambiguity interval, as the 
operator can easily see which objects are far 
away and therefore are measured with a lower 
point density. This image can also help the user 
to decide where exactly to take the next scan. 
To get an overall view of the scanned area, the 
3D window is essential (Fig. 4). All measured 
points are transformed to 3D so that the whole 
point cloud is shown as a three dimensional 
image which gives a good impression of the 
scanned region. The user can turn the object and 
zoom in and out to see the object from any 
points of view. Like in the reflectance image, 
hidden areas can be easily detected in this view. 
Simple measuring features allow the user to get 
the most important measures on site and a 
feeling for the dimensions. The user just has to 
click on two points, and the program calculates 
the distance between them. By using this 
feature, first on-side measurements can be taken 
already in the field which allows the user to 
perform already data evaluation tasks in the 
2.3 LF Modeller 
Light Form Modeller (LFM) has been 
developed specifically to convert 3D point 
clouds into 3D CAD models. Conversion from 
point data to CAD objects is achieved by the 
application of analysis algorithms which have 
been developed to facilitate swift points-to- 
primitives translation. 
Modelling of small or large structures dictates 
that significant numbers of images need to 
be taken from a number of different view 
points and consequently, building a 3D CAD 
model can quickly become a very complex 
undertaking. For this reason, LFM provides 
seamless support to the user to allow rapid 
registration of multiple images from multiple 
viewpoints in order to compose the 3D CAD 

Note to user

Dear user,

In response to current developments in the web technology used by the Goobi viewer, the software no longer supports your browser.

Please use one of the following browsers to display this page correctly.

Thank you.