User's Manual Part 2

Processing Algorithms (draft)
RVP8 User’s Manual
April 2003
5–23
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Range
Azimuth
0
-1
1
0
1-1
Z
output
00
+ Threshold
Threshold if center point is valid but there are no or only one valid neighbor.
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00
Z
0*1
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Range
Azimuth
0
-1
1
0
1-1
Fill thresholded center point with average if there 6 or more valid neighbors.
Z
0*1
Z
*11
Z
01
Z
output
00
+
[
Z
*11
) Z
01
) Z
11
) Z
10
) Z
*1*1)
Z
0*1
]
6
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Range
Azimuth
0
0
-1
1-1
2D Velocity Unfolding Step 1: Search pattern for valid second velocity
PRF2
PRF1
V2
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2
3
1
V1
1*1
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10
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Indicates Thresholded Bin
2D 3x3 Filtering Concepts
The filter has some interesting properties when combined with other algorithms.
Dual PRF Unfolding
Dual–PRF velocity unfolding is computed within the 3x3 filter whenever both are enabled.
There are two steps to the process:
S Step 1: The most recent and the previous ray are used. For every valid point in
the most recent ray, the algorithm performs a search among the three nearest
neighbors in the previous ray to find a valid velocity. The search pattern is shown
at the bottom of the previous figure. This larger selection of alternate–PRF bins