Advanced Cepstral Filtering - Introduction to Imaging from Scattered Fields - page 165

table 10.13 Comparison of Receiver Spacing and
Incident Frequency Wavelength to Illustrate the
Aliasing Threshold Limits for Each Scenario

# of Receivers spacing (m) F inc (GHz)

λ inc (m)

360 0.013 0.030 10

180 0.027 0.033 9

0.038 8

120 0.040 0.043 7

0.050 6

90 0.053 0.060 5

72 0.066 0.075 4

60 0.080 0.100 3

45 0.106

40 0.119

36 0.133 0.150 2

30 0.159 0.300 1

24 0.199

20 0.239

18 0.265

15 0.318

12 0.398

10 0.478

Using the data from Table 10.13, simulations were run for each incident
frequency in the range of the aliasing threshold limit predicted using the rela-
tionship described above. The results of this experiment are shown in Table
10.14 and clearly show the accuracy of predicting when aliasing will occur.
Tables 10.15 through 10.18 also show examples of how applying the random
receiver spacing method introduced in Chapter 6 addresses this aliasing for
the images processed using the cepstrum method for a circle using various
incident frequencies. In addition Tables 10.19 through 10.22 show anti-aliasing
results for various target types demonstrating that the result of applying this
technique to undersampled images is quite favorable in general regardless of
the type of target being imaged.