Plains
Common open areas with brown soil, typically with varying
degree of dry grass cover (
PLMU
,
PLS12
,
PLCI
,
PLS5
).
Open Ground
An open ground with compact bare soil without grass cover,
such as, play grounds (
OGFC
,
OGPA
,
OGMO
).
Quarry
A large stone quarry area mainly with exposed basaltic rock
surface (
QAMO
).
Dry Grass
Open areas covered with dry grass shoots or grass on slopes
cut to the ground level (
DGKO
,
DGKA
).
Forest Fire Marks
Burned grass pastures and/or meadows at different locations
(
BGKH
,
BGCH
,
BGKO
).
Concrete
Bright road grade cement concrete (
CONP
,
COCP
);
Industrial Roof
Industrial grade tin roof tops (
IRTA
,
IRKI
);
Residential
A mixture signature of area covered predominantly with con-
crete slab roofs without little vegetation (
REPG
,
RENS
);
Residential 2
A mixture signature of up-market housing with good tree
cover (
RUNA
,
RUMO
).
Though the study area sub-image was of 1,000 rows and
256 columns, average over whole image (3200 × 256) was
considered. This step is required to reduce the dominance of
any particular material within the scene.
FAR
experiments were
designed to find optimal flat field within urban area. Each can-
didate flat field was selected based on (a) exhibited bright pure
signature, (b) covered sufficient number of pixels (ideally, >16
to reduce the error) (Clark
et al
., 2002), (c) their separation from
the neighboring pixels by visual interpretation of the image, (d)
accessibility (as far as possible) for synchronized field measure-
ments in the future if any. The flat field codes and their ad-
ditional description are: (
OGFC
); (
OGPA
); (
OGMO
); (
PLMU
) – small
island like the open area in Mutha River, enclosed by Mutha
River on one side and a by small channel on another; (
PLCI
),
that is, a large open area near Indrayani River channel; (Sec-
tor 5 -
PLS5
and Sector 12 -
PLS12
);
CONP
(a smaller area used
for parking) these bright pure pixels can be easily demarcated
in the image; (
IRTA
,
IRKI
) and provide large very bright area;
(
QAMO
). Irrespective of weathered rocks at places, it provides
excellent bright signature all across the bands (Table 1).
Table 5. Producer’s Accuracy for IAR / Best Flat Field calibration methods
Expr. no.
Vegetation
Impervious
Soil
Trees
Hyacinth Residential Industrial Upmarket-residential
Plain
Quarry Dry grass Burnt grass
1
1*
0.92
1
2
1
1
1
3
1
1
0.96
1
4
1
0.91/0.9
0.89
0.62/0.61
1
5
1
1.00/0.99
0.89
0.62/0.61
1
6
1
0.43/0.46
1
0.99/1.00
1/0.97
7
1
0.96/0.99
0.83
1.00/0.97
0.80/0.85
1/0.97
0.93/0.96
8
0.38/0.5 0.84/0.89
1
0.89
1
0.97
Table 6. User’s Accuracy for 6S / Best Flat Field Calibration Methods
Expr. No.
Vegetation
Impervious
Soil
Trees
Hyacinth Residential Industrial Upmarket-residential
Plain
Quarry Dry grass Burnt grass
1
1
1
0.71/0.72
2
1
1
1
3
1
0.99
1
1
4
0.24
0.98
0.89/0.94
0.99/0.98
0.69/0.71
5
0.24
0.95
0.84/1
1
0.97/0.94
6
1
1
0.94/0.98 0.63/0.65 0.78/1
7
1
0.96/0.93
0.89/1
0.76/0.94 0.63/0.81 0.74/1
1/0.99
8
0.57/0.63
0.82
0.98
1
0.94/0.98
0.78/1
Table 7. Producer’s Accuracy for 6S / Best Flat Field Calibration Methods
Expr. No.
Vegetation
Impervious
Soil
Trees
Hyacinth Residential Industrial Upmarket residential
Plain
Quarry Dry grass Burnt grass
1
1
0.91/0.92
1
2
1
1
1
3
1
1
0.96
1
4
1
0.9
0.89
0.61
1
5
1
0.98/0.99
0.89
0.61
1
6
1
0.41/0.46
0.85/1.00
1
0.91/0.97
7
1
0.92/0.99
0.89/0.83
0.85/0.97
0.85
0.91/0.97 0.94/0.96
8
0.5
0.86/0.89
1
0.89
0.85/1.00
0.91/0.97
PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
May 2017
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