@InProceedings{Kybic-ICIP1999,
  IS = { zkontrolovano IS No 07 Dec 2003 },
  UPDATE  = { 2003-10-17 },
  author =       {Jan Kybic and Philippe Th{\'e}venaz and Michael
                  Unser},
  title =        {Compensation of Unidirectional Geometric Distortion
                  in {EPI} Using Spline Warping },
  year =         {1999},
  pages =        {168--172},
  booktitle =    {{ICIP'99}: Proceedings of the 1999 {IEEE}
                  International Conference on Image Processing },
  publisher =    {IEEE Computer Society },
  address =      {445 Hoes Lane, Piscataway, NJ, U.S.A. },
  isbn =         {0-7803-5467-2},
  volume =       {II},
  book_pages =   {1276},
  month =        {October},
  day =          {25-28},
  venue =        {Kobe, Japan},
  annote =       {Due to magnetic field inhomogeneities, EPI images
                  are geometrically distorted, predominantly along the
                  phase-encoding direction. Currently, the distortion
                  is either ignored or compensated manually using a
                  warping function defined through a set of
                  landmarks. We propose an automatic method to unwarp
                  the geometric distortion of EPI images by
                  registering them with corresponding undistorted
                  anatomical MRI images. We show that cubic splines
                  are optimal interpolating functions for both
                  landmark interpolation and approximation. We will
                  consequently use the same warping space in our
                  algorithm which replaces landmarks by an image
                  difference criterion. B-splines are used as
                  generating functions, which leads to a fast and
                  accurate computation. Multiresolution gives
                  robustness and additional speedup. The algorithm
                  performance was evaluated using both real and
                  synthetic data and was found superior to the manual
                  method. },
  keywords =     { registration, distortion compensation, MRI, EPI},
  prestige =     { important },
  authorship =   { 80-10-10 },
  project =      { epfl_kybic_thesis },
  psurl =        { [Pdf,300 KB] },
  url =          {ftp://cmp.felk.cvut.cz/pub/cmp/articles/kybic/Kybic-ICIP1999.pdf},
}