@InProceedings{kuhn12a,
  author    = {A.~Kuhn and C.~Rössl and T.~Weinkauf and H.~Theisel},
  title     = {A Benchmark for Evaluating {FTLE} Computations},
  booktitle = {Proc. IEEE PacificVis},
  year      = {2012},
  pages     = {121--128},
  address   = {Songdo, Korea},
  month     = {February},
  abstract  = {The Finite Time Lyapunov Exponent (FTLE) has become a widespread tool
              for analyzing unsteady flow behavior. For its computation, several
              numerical methods have been introduced, which provide trade-offs
              between performance and accuracy. In order to decide which methods
              and parameter settings are suitable for a particular application,
              an evaluation of the different FTLE methods is necessary. We propose
              a general benchmark for FTLE computation, which consists of a number
              of 2D time-dependent flow fields and error measures. Evaluating the
              accuracy of a numerically computed FTLE field requires a ground truth,
              which is not available for realistic flow data sets, since such fields
              can generally not be described in a closed form. To overcome this,
              we introduce approaches to create non-trivial vector fields with
              a closed-form formulation of the FTLE field. Using this, we introduce
              a set of benchmark flow data sets that resemble relevant geometric
              aspects of Lagrangian structures, but have an analytic solution for
              FTLE. Based on this ground truth, we perform a comparative evaluation
              of three standard FTLE concepts. We suggest error measures based
              on the variance of both, the fields and the extracted ridge structures.},
  url = {http://tinoweinkauf.net/publications/abskuhn12a.html},
}