Vaisala RVP900 - Table 59 2 D 3 X3 Speckle Filter Rules

The filter examines 3 adjacent range bins from 3 successive rays to assign a value to the
center point. For each output point, its 8 neighboring bins in range and time are available to
the filter. Only the dBZ, dBT, Velocity, and Width data are candidates for this filtering step.
All other parameters are processed using the default 1D speckle filter.
Table 59 2D 3x3 Speckle Filter Rules
Center Point Action
Assign Threshold Else
Valid Center Point If there are none or only one other
valid point in the 3x3.
Do Nothing. Pass the center point
value as-is.
Thresholded Center Point If there are five or fewer valid
neighbors in the 3x3.
If there are six or more valid
neighbors in the 3x3, average to fill
the center point.
The 2D 3x3 filter fills by interpolation and thresholdw isolated noise bins. The following
figure shows some examples.
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