Digital Signal Processing Reference
In-Depth Information
Figure 1.2. (left) SAR image of Gulf of Oman region and (right) resolution-
scale information superimposed.
by the original image plus 100 times the resolution scale 3 image plus 20 times the
resolution scale 4 image.
In Fig. 1.3, the corresponding SeaWiFS image is shown. The weighting used here
for the right-hand image is the original image times 0.0005 plus the resolution scale
5 image.
In both cases, the analysis was based on the starlet transform, to be discussed in
Section 3.5.
1.4.2 Wavelet Visualization of a Comet
Figure 1.4 shows periodic comet P/Swift-Tuttle observed with the 1.2m telescope
at Calar Alto Observatory in Spain in October and November 1992. Irregularity of
the nucleus is indicative of the presence of jets in the coma (see resolution scales
4 and 5 of the wavelet transform, where these jets can be clearly seen). The starlet
transform, or
B
3
spline a trous wavelet transform, was used.
1.4.3 Filtering an Echocardiograph Image
Figure 1.5 shows an echocardiograph image. We see in this noninvasive ultrasound
image a cross section of the heart, showing blood pools and tissue. The heavy
speckle, typical of ultrasound images, makes interpretation difficult. For the filtered
