Image Processing Reference
In-Depth Information
up the results from all the fusion techniques together facilitates a better comparative
analysis to the readers both in a subjective and objective terms. Therefore, we shall
present combined results of fusion over several hyperspectral datasets using these
techniques explained in this monograph along with some other recently developed
techniques in a later chapter. However, in this chapter we provide the results of fusion
using the Bayesian technique over a single dataset for a quick illustration.
Consider the urban hyperspectral data used in the previous chapter again. These
data depict some region of Palo Alto, CA that has several urban establishments.
The data contain 242 bands of dimensions
each. We initially remove
the noisy and zero-response bands as done for the previous solution. We process the
entire dataset to obtain a grayscale fused image. First we compute the sensor selectiv-
ity factor
for every pixel in the data which is the normalized product of two quality
measures. The second step consists of an iterative procedure to generate the fused
image F . The fused image so obtained represents the best possible image estimated
under the given constraints for the given hyperspectral data. This resultant image, as
shown in Fig. 5.2 a is a combined response of the scene over an approximate band-
width of 2200 nm. The fusion results are also often provided as color (RGB) images
as they provide a better visual interpretation of the scene. Most of the fusion solu-
tions for hyperspectral data generate the color images using some pseudo-coloring
schemes. In order to illustrate the RGB versions, we first partition the input data into
three subsets. While there could be various strategies for this partitioning, we follow
a simple one. We obtain three groups by sequentially partitioning the data along the
wavelength such that every groups contains nearly a similar number of bands. These
three groups are processed independently using the Bayesian technique to generate
the corresponding three fused images. These images are then assigned to the red,
Fig. 5.2 Results of Bayesian
fusion of the urban image from
the Hyperion. a Grayscale
fused image, and b RGB
fused image (©2013 Elsevier,
Ref. [91]). (Color is viewable
in e-book only.)
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