CIP A 2003 XIX th International Symposium, 30 September - 04 October, 2003, Antalya, Turkey
figure 2- 1:10000 Vector map overlaid onto the orthoprojected image
4. SIGNIFICANT BANDS SELECTION
The second step was to select the most useful bands for the
detection of archaeological features and anomalies. These can
be identified by the texture, soil moisture and vegetation cover
differences that are produced by buried structures.
The peculiarity of the investigated objects led us to select bands
renouncing to the principal components analysis; we proceeded
with a visual interpretation taking care of the bibliographic
references. A total of 10 of the 102 available bands of the
MIVIS sensor were chosen:
a) 4 in the visible range (b2= 0.4600 pm, b7=0.5600 pm,
bl 1= 0.6400 pm, b20= 0.8200 pm) for the contextual
location;
b) 2 in the near infrared range (b23= 1.2750 pm, b28=
1.5250 pm), for vegetation cover anomalies;
c) 1 in the medium infrared range (b52= 2.1790 pm) for
soil moisture;
d) 3 in the thermal infrared range (b93= 8.3859 pm,
b97= 10.0200 pm, b 101 = 11.9450 pm) for termal
variation on the ground.
No calibration have been made as no calibration file was
available for the test image. That has not be considered
fundamental because relative, and not absolute, differences
between objects had to be investigated.
5. TEST AREAS SELECTION AND IMAGE MASKING
Queries and spatial analysis performed on the data collected in
the Marchesato di Saluzzo GIS permitted to choose 2 test areas
responding to the appropriate archaeological needs:
5.1 The Sant’Ilario monastery.
This monastery is near the town of Revello, close to the Po
valley mouth. The documentary sources refer to three villages
in the second half of the XII Century. Today there is no sign of
these settlements which in the documents were known as
Sant’Ilario, Viverio e Paralupo. The XII Century documents
also refear to a road called “via publica” which was situated
near the monastery.
5.2 The San Massimo church.
The site of this church was between the Revello and Envie
towns. Thanks to a document of the half of the XIII century, we
know there was a very important road called “v/a monnea
superius” which was near San Massimo church. The name of
this road seems to suggest a paved road. This road was part of a
longer, probably Roman route, which joined the town of
Saluzzo with the town of Bricherasio.
We built and applied an opportune mask to bound these two
areas. A mask is a binary image that consists of values of 0 and
l.When a mask is used in a processing function, the areas which
have values of 1 are processed and the masked 0 areas are not
included in the calculations. This procedure has permitted us to
limit the investigation and the radiometric bothers.
6. IMAGE CLASSIFICATION AND VALIDATION
Nine regions of interest (ROI) were selected inside the sample
areas: buildings, industrial buildings, water, streets, soil
moisture, orchards, vegetated fields, non-vegetated fields,
shadow zones.
A spectral angle mapper classification with an angle threshold
of 0.10 (radians) was applied. For the validation of the
classification of the eight classes the correspondent confusion
matrix was calculated(table 3). It shows a correct classification
of ROIs, although in the next future a certification on the
ground could be necessary.
class
unclassified
Industrial
buildings
orchards
Streets
buildings
Non-
vegetated
field
water
Vegetated
fields
Shadow
zone
Soil
moisture
Total
unclassified
227651
0
0
0
0
0
0
0
0
0
227651
industrial buildings
0
846
0
0
0
0
0
0
0
0
846
orchards
0
0
31544
0
0
0
0
0
0
0
31544
streets
0
0
0
13219
0
0
0
0
0
0
13219
buildings
0
0
0
0
1191
0
0
0
0
0
1191
non-vegetated field
0
0
rö
0
0
9356
0
0
0
0
9356
water
0
0
0
0
0
0
307
0
0
0
307
Vegetated fields
0
0
0
0
0
0
0
19414
0
0
19414
Shadow zone
0
1)
0
U
0
0
0
0
1052
0
1052
Soil moisture
0
1)
0
0
0
0
0
0
0
35870
35870
Total
227651
846
31544
13219
1191
9356
307
19414
1052
35870
340450
Tab. 3- Confusion matrix of the nine selected class
