Changes between Version 9 and Version 10 of Tutorial/CorrelationImageVelocimetryOptimisation

Timestamp:

Jan 27, 2015, 5:09:12 PM (9 years ago)

Author:

vaillant1p

Comment:

--

Tutorial/CorrelationImageVelocimetryOptimisation

@@ -16 +16 @@
 It is now possible to adjust the search range, using prior knowledge on extremal velocities, see histograms displayed by '''uvmat''' in pixel  coordinates. We introduce estimated bounds on each velocity component,  [min] to -2 and [max] to 6 for ’u’ and (-3, 3) for ’v’, and press the  button '''[Search Range]'''. The optimum search ranges and shifts (for the given correlation box) are  now displayed: [33 25] and [2 0] respectively.
 
-Let us run again  PIV with '''[!CorrBoxSize]'''=[19 13] and '''[!SearchBoxSize]'''=[27 25] with '''[Shift]'''=0. (limiting ourselves to CIV1), and visualise the result with '''uvmat'''.  Many black vectors (F=-2) are obtained, showing that the search domain  is too small, so that the correlation maximum is constrained by the  limited search interval. Using  '''[!TestCiv1]''' , it can be seen that the correlation maximum is indeed on the edge of the Search box, a lot of black error flag will thus be seen on the velocity image. Then come back to the good parameters.
+Let us run again  PIV with '''[!CorrBoxSize]'''=[19 13] and '''[!SearchBoxSize]'''=[27 25] with '''[Shift]'''=0. (limiting ourselves to CIV1), and visualise the result with '''uvmat'''.  Many black vectors (F=-2) are obtained, showing that the search domain  is too small, so that the correlation maximum is constrained by the  limited search interval. Using  '''[!TestCiv1]''' , it can be seen that the correlation maximum is indeed on the edge of the Search box, a lot of black error flags will thus be seen on the velocity image. Then come back to the good parameters.
 
 == !CorrSmooth ==