The document discusses the use of laser scanning surveys to document cultural heritage. It describes how laser scanning captures precise 3D geometric data about objects through time-of-flight measurement. Raw point cloud data is captured, then processed to clean noise, register multiple scans, and generate a triangulated mesh model. The laser scanning survey provides an accurate digital representation that supports preservation and protection of cultural heritage objects.

1. THE SURVEY AS BASIS FOR
DOCUMENTATION OF CULTURAL
HERITAGE
PROF. LAURA BARATIN
Università degli Studi di Urbino “Carlo Bo”
Dr. DANIELA PELOSO
Arch. MICHELE CURUNI

2. The survey open system of
knowledge
• The first level for the preservation
and conservation is knowledge
• Knowledge means in each case to
document
• The documentation is an essential
support for the protection of cultural
heritage

3. The survey open system of
knowledge
The survey of each body architecture
must be designed so that it can be
transformed into an information
system
Within the information system will
put the various information that
can be accumulated in recent times
in different forms

4. The knowledge
• The geometric model – The architectural survey
• The iconic model - as analysis of the composition
of space and how overview of its volume and its
spaces
• The distribution model - such as analysis of
routes spaces of their distribution and their use
• The model constructive - like technical analysis
of the parties and structural building
• The model of the state of conservation as
analysis of changes and degradation

5. Palazzo Pepoli Campogrande - Bologna
Survey geometrical formal
17.72
1.34
1.34 1.34 1.34
7.52 7.24
6.56
H. 5.30 H. 5.30
H. 3.70
2.72
0.23
7.95
8.16
7.97
8.05
9.59
10
11
.70
.03
3.62
0.54
3.24
H. 3.13
2.99
3.45
.76
.51
10
10
STALE DE' PEPOLI
1.68
6.79 7.06
1.25 1.24
1.38
1.36 2.61
B
1.37
0.32
0.95
7.38
2.44
2.50
1.34
2.67
2.54
H. 2.46
3.6
1.22 7
0.69
1.50 1.50
1.50 0.62 60.36
7.06 3.74
1.22 3.95 2.50 1.32
2.77
5.01 1.28 3.03
7.08 0.41 1.02 2.95
2.99
ASCENSORE
2.60
3.86 3.13
7.85 H. 4.59 6.15
BOTTE 5.25
4.38
6.3
8.0
4.37
4.09
9.3
3.76
8.6
5.8
4 1.12 1.45
7
9
H. 6.30
5
9
7.60 4.96
1.62 1.19
2.83
5.86
2.77
6.20
1.58
2.68
3.72
H. 6.30
0
6
5.9
H. 2.45 6.4 5.11 H. 6.30 0.95
7.70
1.47
1.89
10
1.71
7.37
3.94
8.32
2.10
.19
7.04
4.21
6.92
6.90
6.78
6.95
5
6.74
8
3.93 2.21 2.24
7.8
1.63
3
9.0
5.25
8.4
5.03
9.4
3.33
H. 3.70
6.66
4 H. 5.80 08
13.
1.21
5.8
3.86
6.2
3.91
1.38
2.76
3.54
3.40
H. 6.30
3.75
9.78
3.70
3.69
1 8

6. Palazzo Ducale di Urbania
Abaco capitals

7. Palazzo Pepoli Campogrande - Bologna
Historical Evolution

8. Palazzo Pepoli Campogrande – Bologna
Historical Evolution

9. Palazzo Ducale di Urbania
Iconic Model

10. Palazzo Ducale di Urbania
Iconic Model

11. Palazzo Ducale di Urbania
Distribution Model

12. Palazzo Ducale di Urbania
Analysis of the deterioration of the columns

13. • The relief requires the integrated
use of various procedures and
documentation of measurement
• The objective is to arrive at a
correct representation as well as
metrically exact object of study

14. Traditional survey or direct survey
Traditional means Survey relief through
simple tools
Instrumental Survey
Instrumental survey means detect
architecture with complex instruments:
• Topographical Survey
• Photogrammetrical Survey
• Survey using 3D laser scanner

15. Topographical Survey
• The topographical survey is the
preliminary phase of survey
activities
• The topographical survey
serves to create a rigid cage
around the object

16. Photogrammetrical Survey
The photogrammetrical survey
is a measurement procedure
that uses photographic images
of an object for the purpose of
obtaining the different 2D and
3D sizes

26. LASER SCANNER SURVEY
DATA ACQUISITION
A LASER SCANNER IS CONCEPTUALLY QUITE A SIMPLE INSTRUMENT:
A LASER BEAM SCANS THE REAL OBJECT, THEN CREATES A
MATHEMATICAL MOCK-UP COMPOSED OF A SET OF POINTS IN THREE-
DIMENSIONAL SPACE, ARRANGED ACCORDING TO A REGULAR GRID
WITH A KNOWN STEP SIZE
THIS GRID, KNOWN AS POINT CLOUD, IS A SET OF THREE-
DIMENSIONAL COORDINATES IN A REFERENCE FRAME CONNECTED
WITH THE INSTRUMENT
SCANNER SYSTEMS WORK AUTOMATICALLY, CAN GATHER
HUNDREDS OF POINTS EACH SECOND, AND, ACCORDING TO THE
EMPLOYED SENSOR, CAN ACTUALLY CREATE VIRTUAL COPIES OF
REAL OBJECTS REGARDLESS OF THEIR SIZE
CLEARLY, THE SPEED OF DATA ACQUISITION AND THE BULK OF
GATHERED DATA IN A SHORT TIME SPAN ARE THE MAIN FEATURES
DEFINING THIS TECHNOLOGY AND SHOWING ITS GREAT POTENTIAL

27. Measurements
1. Distance accuracy (+/- 4mm)
2. Angular measurement (+/- 60 micro-radians)
3. Intensity (based on the object reflection
factor)
Saved in the Data Base

28. Laser property
laser direction Scanning speed
>1,000 pts/sec, max
Space between the points
up to 0.25mm
origin mirror
Safe for eyes
“Class 2”
(USA)
Cyrax 2500

29. Spot Accuracy and Sizes
< 6mm @ 50m
Accuracy: 6 mm @ 50 m
Precision: 2 mm @ 50 m
Spot sizes: 6 mm @ 50 m

30. LASER SCANNER SURVEY
DATA ACQUISITION
THE KIND OF LASER SCANNERS THAT CAN SURVEY LARGE OBJECTS, AT A
DISTANCE RANGING BETWEEN 10 AND 800 M, ARE THOSE THAT USE THE TIME-OF-
FLIGHT (TOF) MEASUREMENT TECHNIQUE
TOF SCANNERS CALCULATE THE THREE-DIMENSIONAL COORDINATES OF EACH
POINT FROM THE MEASUREMENT OF THE EXPIRED TIME BETWEEN THE EMISSION
OF THE LASER BEAM AND THE DETECTION OF THE RETURNING BEAM AFTER IT
HIT THE OBJECT: THE INSTRUMENT CALCULATES THE POLAR COORDINATES
TAKING THE DISTANCE BETWEEN THE CENTRE OF THE INSTRUMENT AND THE
POINT, PLUS THE AZIMUTH AND ZENITH ANGLE OF THE EMITTED BEAM
THE LASER BEAM IS SENT TOWARDS THE OBJECT, THANKS TO ITS
OPTICAL/MECHANIC POINTING SYSTEM, WHILE THE AZIMUTH AND ZENITH
ANGLES ARE DISCRETELY CHANGED

31. LASER SCANNER SURVEY
DATA ACQUISITION
THE MAIN FEATURES OF THE INSTRUMENT, THAT DEFINE ITS
QUALITY AND FUNCTIONALITY IN A GIVEN ENVIRONMENT, ARE THE
FOLLOWING:
THE RANGE OF DISTANCES WITHIN WHICH THE SCANNER IS
ABLE TO MEASURE THE OBJECT;
SCAN SPEED, USUALLY MEASURED IN POINTS PER
SECONDS;
THE FIELD OF VIEW, I.E. THE ANGLE (IN DEGREES) THAT THE
SCANNER CAN COVER WITH A SINGLE SCAN;
SINGLE POINT ACCURACY, I.E. THE PRECISION OF THE
MEASURED COORDINATE, AND THE SPOT SIZE, DEFINING
THE NARROWNESS OF THE LASER BEAM

32. LASER SCANNER SURVEY
DATA ACQUISITION
THE INSTRUMENT IS
CONNECTED TO A LAPTOP
PC FROM WHICH THE
SCANNING OPERATIONS CAN
BE SET UP AND CHECKED.
THIS SETUP HAS THE
ADVANTAGE OF ALLOWING A
REAL-TIME CHECK OF THE
SCAN RESULTS

33. LASER SCANNER SURVEY
DATA ACQUISITION
A SCAN AND ITS DIGITAL PICTURE SHOT BY THE
INTEGRATED DIGITAL CAMERA OF A LEICA HDS2500

34. LASER SCANNER SURVEY
POST PROCESSING
THE RAW CLOUD, AS FED FROM THE SCANNER INTO THE PROCESSING
ENVIRONMENT, NEEDS MOST OF THE TIME TO BE “CLEANED”.
LASER SCANS QUITE OFTEN INCLUDE THE SURVEY OF UNWANTED OBJECTS, SUCH
AS TREES, CARS, ELEMENTS ON THE BACKGROUND; THEREFORE WE MUST LIMIT
THE CLOUD TO THE SURVEYED OBJECT, FOR A BETTER DISPLAY AND IN ORDER TO
AVOID THE PROCESSING OF USELESS POINTS BY THE PC.
ALL THESE UNWANTED ELEMENTS, THAT WE COMMONLY DEFINE AS NOISE, MUST
OF COURSE BE MANUALLY REMOVED BY THE USER.

35. LASER SCANNER SURVEY
POST PROCESSING
AFTER NOISE SUBTRACTION, THE SCANS USUALLY ARE MERGED INTO ONE
1
2
THE REGISTRATION AND MERGE OF THE NUMEROUS SCANS TAKEN AT THE
GGANTIJA SITE WAS UNDOUBTEDLY ONE OF THE MOST COMPLICATED STAGES OF
THE WHOLE SURVEY CAMPAIGN, BOTH SINCE THE HIGH NUMBER OF SCANS AND
THE UNIQUE MORPHOLOGICAL COMPLEXITY OF THE SITE.

36. LASER SCANNER SURVEY
POST PROCESSING
PICTURE OF THE OVERALL POINT
MODEL OF THE BIG TEMPLE

37. LASER SCANNER SURVEY
POST PROCESSING
THE SURVEY IS GEO-REFERENCED TO THE NATIONAL REFERENCE SYSTEM

38. LASER SCANNER SURVEY
POST PROCESSING
THE NEXT PART OF THE POST PROCESSING STAGE IS THE ONE MORE
CLOSELY RELATED TO THE FINAL DESIRED OUTCOME: USUALLY,
ALMOST ALL OPERATIONS GO THROUGH THE GENERATION OF A
TRIANGULATED SURFACE MODEL, CALLED MESH.
A MESH IS AN APPROXIMATE DESCRIPTION OF A THREE-DIMENSIONAL
SURFACE WITH A GRID OF TRIANGLES