Vaisala RVP900 - Figure 45 1 D Speckle Filtering Algorithm; Table 58 1 D Speckle Filters

The 1D and 2D speckle filters are enabled using the soprm command, Input 2 (see 8.4
Setup Operating Parameters (SOPRM) (page 239). If both are turned on, the 1D filter is
applied first.
More Information
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Speckle Filter (page 44)
7.5.3.1 1D Speckle Filter
A ray is the basic azimuth unit of RVP900 (for example, 1°) over which the samples are
averaged to obtain the output base data (T, Z, V, W).
For this
filter, a speckle is defined as any single, valid bin (not thresholded), having
thresholded bins on either side of it in range. Any such isolated bin in a ray is set to
"threshold".
1D Speckle Filtering
Input Ray
Output Ray
Range
Indicates Thresholded Bin
Indicates Valid Bin
Indicates Speckle
X
Figure 45 1D Speckle Filtering Algorithm
Table 58 1D Speckle Filters
Purpose Relevant Data Types
Reflectivity data dBT, dBZ, ZDR
LDR when using dual-pol
Doppler data V, W, PhiDP, RhoHV
KDP when using dual-pol
When either speckle filter is switched on, it is applied in HydroClass.
Each filter must be switched on or o, depending on the nature of the targets being
observed. For example, when making a clutter map of the area, it is recommended that you
switch both speckle
filters o.
7.5.3.2 2D 3x3 Speckle Filter
This is a 3x3 azimuth/range filter to remove single point targets and interpolate single point
gaps surrounded by valid data.
The 2D 3x3 speckle filter performs data filling of "missing speckles" as well as eliminating
isolated speckle bins.
Chapter 7 – Processing Algorithms
211