Building Earth Observation Cameras

271Hyperspectral Imaging

untapered edge, the center wavelength and bandwidth remains constant.

To control out-of-band radiation in the wedge lter, a blocking lter whose

passband covers the spectral region of interest is mounted on the opposite

side of the substrate. Some of the aspects related to the lter fabrication pro-

cess may be found in the work by Rosenberg et al. (1994).

Spatial

dimension

Spatial

Spectral

Blocking filter

Substrate

Filter forming

coating layers

Detector array

(a)

(b)

Spectral dimension λ

λ

1

x

1

y

x

n

λ

n

λ

max

λ

min

Detector area array

Wedge filter

Imaging optics

Spacecraft motion

FIGURE 8.15

(a) Schematics showing wedge lter focal plane arrange ...