Image Processing Reference

In-Depth Information

Fig. 11.5
General scheme for the application of the ARSIS concept using a multiscale model

(MSM) and its inverse (MSM-1)

details or approximation observed in the representation
A
and those observed in the

representation
B
. The IBSM may relate approximations and/or details for one or

more resolutions and one or more spectral bands. As an example, the Model 2

relates the details observed at resolution n°3 in the image
A
and the image
B
k
using

a linear relationship (Ranchin and Wald
2000b
).

The High Resolution Inter-Band Structure Model (HRIBSM) performs the

transformation of the IBSM with change in resolution. This operation is not

straightforward as the former ones. Many studies have demonstrated the influence

of the spatial resolution on the quantification of parameters extracted from satellite

imagery (Lillesand and Kiefer
1994
; Woodcock and Strahler
1987
). To our knowl-

edge, there is no published fusion method that has paid particular attention to this

point and the HRIBSM is often set identical to the IBSM. Ranchin et al. (
1994,

2003
) performed a multiscale synthesis of the parameters of their IBSM from reso-

lution n°3 to resolution n°2.

To summarize, the operations are typically performed as follows. First, the MSM

is used to compute the details and the approximations of image
A
(Step 1 in

Fig.
11.5
). The same operation is applied to image
B
(Step 2). The analysis is per-

formed for several resolutions, up to
n
in Fig.
11.5
- that is (
n −
1) iterations for the

analysis of the image
A
and (
n −
2) iterations for that of
B
kl
. These analyses provide

one approximation image and several images of details for
A
and
B
. The known

details at each resolution are used to adjust the parameters of the IBSM (Step 3).

The HRIBSM (at resolution n°2 in Fig.
11.5
) is derived from this model, which