to its resolution (1 m), and fused using the Ehlers fusion method. The scale ratio
between the panchromatic and the multispectral data sets varied from 1 : 4 to 1 : 32.
Results are shown in Figures 2.3–2.9. To demonstrate the effects of fusion on
resolution and spectral characteristics, only single bands of the multispectral data sets
are displayed.
In all images the fusion could improve the spatial resolution of the original
multispectral image. But if the scale ratio between the high-resolution panchromatic
image and the low-resolution multispectral image exceeds 1 : 10, artifacts from the
TABLE 2.1 Multisensor Remote Sensing Data Sets for Study Site (in Chronological
Order)
Satellite Sensor Recording Date
Recording Mode
Ground Sampling Distance
Landsat 5 TM December 21, 2004 Multispectral (six bands) 30 m
SPOT-2
April 21, 2005
Multispectral (three bands) 20 m
IKONOS
June 18, 2005
Panchromatic
1 m
Multispectral (four bands) 4 m
SPOT-5
June 19, 2005
Multispectral (four bands) 10 m (short-wave infrared
(swir): 20 m)
DMC
July 28, 2005
Multispectral (three bands) 32 m
RapidEye5
August 16, 2009
Multispectral (five bands) 6.5 m (resampled to 5 m)
FIGURE 2.3 Panchromatic IKONOS image (left) recorded on June 18, 2005, and equivalent
multispectral band 3 (red) resampled to 1 m (right).
18
SCALE ISSUES IN MULTISENSOR IMAGE FUSION