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3.2.16 Initial Global Search

<initial_global_search></initial_global_search>

  • off Default Setting
  • on

In some cases, the structural image and the diffusion weighted images may have very different translation and rotation. In these cases, the steepest-descent based optimization scheme employed in the registration framework may fail and get stuck at a local minima.

When this setting is turned on, an initial rigid-body search is performed with an evolutionary genetic algorithm optimizer. The individuals used in the population for the genetic algorithm cover a wide range of translations and rotations in between -PI/4 to +PI/4.

The default setting is off because in most cases the structural and b0 images will have similar transformations but if the registration fails because of big rotations, it is suggested to turn this setting on and re-run the processing from step 0.