Image Processing Reference
In-Depth Information
21(f) in addition to the blood flow component, we observe that the clutter component (-
0.08*
fs
) remains on the negative-side under the effect of the filter element. In the negative-
side output waveform at the zero baseline-shift in Fig. 21(g), the separation of the clutter
component (-0.08*
fs
) is observed on the negative-side. Moreover, in the power spectrum in
Fig. 21(h), a clutter component and a DC component are detected. When the baseline shift is
+0.4*
fs
, the spectrum image and Doppler audio must generate a negative region larger than
a positive region. The positive-side output waveform after the baseline shift in Fig. 21(i)
shows the disappearance of the clutter component (+0.24*
fs
). Moreover, we confirm the
absence of the blood flow component in the power spectrum shown in Fig. 21(j). We also
confirm that a novel blood flow component (-0.76*
fs
), which is an alias component (+0.24*
fs
),
is outputted into the negative-side output waveform after the baseline-shift in Fig. 21(k),
except for the clutter component (-0.08*
fs
). Moreover, in the power spectrum in Fig. 21(l), we
confirm that the blood flow and clutter components are separated on the negative-side.
2
Power (dB)
Amplitude
40
0
20
0
-2
-fs
/4
0
fs
/4
fs
/2
Freq
0
10
20
30
40
50
Time (1/
fs
)
2
Amplitude
Power (dB)
40
0
20
0
-2
0
10
20
30
40
50
Time (0 5/
fs
)
-fs
-fs
/2
0
fs
/2
fs
Freq
1
Amplitude
Power (dB)
40
0
20
0
-1
Time (0 5/
fs
)
-fs
fs
/2
fs
0
10
20
30
40
50
-fs
/2
0
Freq
1
Amplitude
Power (dB)
40
0
20
0
-1
Time (0 5/
fs
)
0
10
20
30
40
50
-fs
-fs
/2
0
fs
/2
fs
Freq
1
Amplitude
Power (dB)
40
0
20
0
-1
Time (0 5/
fs
)
-fs
-fs
/2
0
fs
/2
fs
0
10
20
30
40
50
Freq
1
Amplitude
Power (dB)
40
0
20
0
-1
Time (0 5/
fs
)
0
10
20
30
40
50
-fs
-fs
/2
0
fs
/2
fs
Freq
( )
p
(
f
)
(l) spectrum of (k)
Fig. 21. Simulation waveform and spectrum of complex IIR filter system.