Mode-ratio bootstrapping method for PIV outlier correction

This paper proposes a new method for correcting spurious displacement vectors obtained by using particle image velocimetry. Unlike methods that generate and use statistics from neighboring vectors toward outlier identification, a bootstrapping process is employed to generate statistics for each component. The mode-ratio criterion, defined as the normalized absolute value of the difference between the mode of the generated statistics and the actual value on the field, is used to identify and tag spurious components. The bootstrapping process is repeated to generate new statistics from the untagged components. This process is then repeated multiple times. The resulting mode field is used as the correction field. Two different displacement fields, each with a different error type, are artificially generated to evaluate the performance of the method. The evaluation is done by measuring the deviation between the resulting mode field and the perfect component field. The method is then tested on a real turbulent jet flow, obtained from www.pivchallenge.org, and the effect of the spatial gradient is discussed.