Page 245 - Digital Analysis of Remotely Sensed Imagery

Image Enhancement 209

(a)

(b)
FIGURE 6.4 An example of linear nontruncating contrast stretching. (a) Raw
image of IKONOS band 3. It is not so easy to interpret because of its dark
tone; (b) image of the same band whose contrast has been linearly
stretched. More details become visible after its tone is manipulated.
Nontruncating means that degree of stretching is limited.

table is a means of visualizing the content of a single image to maximize
its effectiveness of communication. However, the generation of a
meaningful and satisfactory visualization requires repetitive efforts
in fine tuning the output values for every given input value. This task
is made more challenging if the image is color (Fig. 6.6). Illustrated in
this example is a visualization of sea surface temperature derived
from Advanced Very High Resolution Radiometer (AVHRR) data.