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4.2 Data Preprocessing
and if ∆v adj < 0
v adj =v
for v < v max
v adj =v − 2v enc for v ≥ v max (4.1)
If a v enc adjustment was done, the value v adj is stored in the intermediate file as
well.
An automatic v enc correction is possible as well. This assumes a temporal field,
since this correction analyzes the temporal course of the velocity values. Figure 4.3
illustrates the typical temporal course of a velocity value with aliasing.
Figure 4.3: A typical temporal course of a velocity value with aliasing effect from
[Reiter2007]
By definition aliasing in v i (t n ) is present if
v i (t r ) − v i (t r+1 )
> v enc
v i (t s ) − v i (t s+1 ) < −v enc
(4.2)
which applies exactly once. Then a replacement for
v i (t n ) → v i (t n ) + 2v enc for n = r + 1, ..., s
v i (t n ) → v i (t n ) − 2v enc for n = s + 1, ..., r
and r > s
and r < s
(4.3)
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