748
October 2016
PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
I
mage
C
ollection
The scientific monochrome camera used
in the experiment is equipped with a
SONY CCD ICX274AL sensor (Table
1[a]) (SONY, 2016). To avoid quality dif-
ferences due to sensor variation in image
collection, the high resolution Pan image
was collected using the camera without
a light filter, whereas the blue, green,
red, and near infrared (NIR) bands of the
high resolution MS image were collect-
ed using the same camera with dichroic
color filters from Edmund Optics (Table
1[b]) (Edmund Optics, 2016).
The scene and photo lab setup used for
this experiment are shown in Figures 1
and 2, respectively. From Figure 1, the
scene contains three industry standard
test charts. The industry standard lights
used to illuminate the scene were four
SoLux MR16 4700K lamps that replicate
natural daylight (McGuire, 1995), two on each side.
Table 1. Sensor and color filter specifications, and exposure settings
for image collection.
(a)
Specifications of the sensor SONY CCD ICX274
Resolution
2 MP, 1620×1220 pixels
Sensor size
1/1.8” (diagonal 8.923mm)
Sensor chip size
8.50mm (H) × 6.80mm (V)
Pixel size
4.4 x 4.4 μm
(b)
Spectral bandwidth of the dichroic color filters
Filters
Spectral range (bandwidth) (µm)
Pan (No filter)
395-1000 (bare CCD sensor)
Blue
390-485
Green
490-585
Red
580-700
NIR
695-1200
(c)
Image illuminance and exposure time
Illuminance
Exposure time
40 lux
20 ms
250 lux
20 ms
18 lux
100 ms
250 ms
The illuminance of the scene and the exposure times for
image collection are shown in Table 1(c). Because the
lab lighting was not as strong as the daylight for sat-
ellite image collection, the exposure time was extended
to ensure that sufficient photons were collected by the
sensor. Since illuminance on the earth’s surface has
seasonal and regional differences, the scene was illu-
minated with two different light intensities and the im-
ages were collected with three different exposure times.
Even though the lab setting does not accurately simu-
late the circumstances present during actual satellite
image collection, the quality comparison of this study
is not compromised. This is because our purpose is to
compare the qualities between an original high resolu-
tion MS image and its corresponding pansharpened MS
image.
Figure 1. Scene used for the Pan and MS image collection. (Middle) ISO Standard Chart
(12233:2014); (Lower left) Noise Contrast Chart (15739); (Lower right) MacBeth Color
Checker; and (Other areas) other color imaging targets.
Figure 2. Lab setting for the Pan and MS image collection.
