Changes between Version 36 and Version 37 of Tutorial/CorrelationImageVelocimetryOptimisation
 Timestamp:
 Mar 24, 2015, 10:26:01 AM (9 years ago)
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Tutorial/CorrelationImageVelocimetryOptimisation
v36 v37 49 49 The '''[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. 50 50 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]''' + 6in 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'''=5.51 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]''' +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. 52 52 53 53 The 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 subimages to perform the deformation.