Changes between Version 36 and Version 37 of Tutorial/CorrelationImageVelocimetryOptimisation


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Timestamp:
Mar 24, 2015, 10:26:01 AM (9 years ago)
Author:
vaillant1p
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  • Tutorial/CorrelationImageVelocimetryOptimisation

    v36 v37  
    4949The '''[CIV2]''' operation repeats the '''[CIV1]''', but it uses the result of Patch1 as a prior estimate. Therefore while Civ1 is purely local, Civ2 restricts the research to a correlation maximum which is close to the values obtained for neighboring vectors.
    5050
    51 The parameter  '''[num_SearchBoxShift] '''therefore does not appear in the Civ2 panel, as it is given at each point by the result Patch1. The other parameters have the same meaning as for Civ1. The search box must be small enough to effectively reduce the research to the prior estimate. Take '''[!CorrBoxSize]''' +6 in each direction (providing a margin of 3 pixels on each side of the correlation box). Since it is the final result, you can optimise the grid by taking '''Dy'''=5.
     51The parameter  '''[num_SearchBoxShift] '''therefore does not appear in the Civ2 panel, as it is given at each point by the result Patch1. The other parameters have the same meaning as for Civ1. The search box must be small enough to effectively reduce the research to the prior estimate. Take '''[!CorrBoxSize]''' +13 in each direction (providing a margin of 3 pixels on each side of the correlation box). Since it is the final result, you can optimise the grid by taking '''Dy'''=5.
    5252
    5353The parameter '''[deformation]''' (check box) improves the prior estimate by deforming the subimage taking into account the velocity gradients, so it can improve the processing in zones of strong shear or strong rotation, like vortex cores. It involves an interpolation of the sub-images to perform the deformation.