m. The arrangement of the these elements
on the focal plane is shown in Fig.4
non noggmm
Biii ecc A
i:Hnn nomm
3 lóm
(em Som] ioi
dn DA
ber Pret emis
Fig.4 Arrangement of sensor elements
In multi-spectral band, this 164m sensor
aparture corresponds to 16m on the ground,
and in panchromatic band 8um sensor apar-
ture corresponds to 8m on the ground.
5. SIMULATION
The simulation was conducted with a postu-
rated point spread function(PSF) of AVNIR :
that is the PSF is assumed to be a box type
Then the moduration transfer function(MT
F) of the sensor element is to be a sinc
function.
The simulations was done on four problems:
(1) Aliasing effect comes from the inherent
characteristic of pushbroom scan
(2) Degradation of spatial resolution comes
from cross talk
(3) Atmospheric effect on spatial resolu-
tion
(4) Motion degradation in along track reso-
lution
5.1 Aliasing by inherent sampling process
In this simulation, linear zone plate(LZP)
was used as the input. This is a modulation
of circular zone plate used for TV resolu-
tion test. Radiance level of LZP r(x)
changes with coordinate x as follows.
r(x) = cos ( x2) (11)
And the spatial frequency U(x) is expressed
in next formula.
ul{xls | 12. + 27m) 1223.3) CAM (12)
An example is shown in Fig.5 In this Fig.
(a) is the power of LZP input. (b) is the
out-put power of ideal case in which picth
Of sensor element is very short, sampling
frequency is very high and no aliasing. (c)
is output power of usual case in which
pitch of sensor element is equal to the
sensor dimension. There is some bump of
power in (c) because of aliasing.
2
X
0.04
LEVEL
0.00
0 64 128 192
FREQ.
(a) Power of LZP input
]
0.0
| toti o eren,
pte fe og Ry qe 5 y
64 128 192 : 256
FREQ.
LEVEL
0.00
(b) Power of ideal sampling pitch
2
X
0.06
LEVEL
0.00
(c) Power of usual sampling pitch
Fig.5 Aliasing effect of sampling pitch
Although this simulation was conducted with
a posturat
there will
output.
5.2 Degrad:
Usualy à
cross talk
LEVEL LEVEL LEVEL LEVEL
0 32.5486 0 0.571429 0 13.7486 0 0.571429
e
Fig.6 De,
