References for PIV Image bias

References for PIV Image Bias Correction

Suggestive correctional methods for PIV image biasing caused by a rotating mirror system

D. Lee and S. H. Chung
Department of Mechanical Engineering, Seoul National University, Seoul 151-742, Korea

K D. Kihm
Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843-3123, USA.

A rotating mirror is widely used to generate the velocity shift that can resolve the directional ambiguities of PIV (particle image velocimetry) measurements. The rotating mirror system inevitably creates the normal displacement of the resulting PIV images and causes systematic image errors. Two corrective methods are proposed to eliminate or reduce the image biasing in PIV system. The use of two linearly traversing mirrors, instead of a single rotating mirror, shows that image biasing can be eliminated and the velocity shift well generated. As a second option, two co-rotating mirrors, instead of one, can reduce the image biasing with a maximum velocity shift available. Detailed imaging kinematics of the two suggestive methods are presented to lead to designing of practical devices that improve the PIV capabilities by reducing the systematic image errors

more details, click here [239KB in PDF]

Correction of PIV Image Biasing using Two Co-Rotating Mirrors

K D. Kihm
Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843-3123S.

D. Lee and S. H. Chung
Department of Mechanical Engineering, Seoul National University, Seoul 151-742, Korea

The rotating mirror in particle image velocimetry (PIV) is generally used to provide an image shift to resolve the directional ambiguities for the recorded particle image pairs. However, the reflected image from the rotating mirror inevitably creates normal velocity components with respect to the image plane, and this normal component causes spatially distributed systematic image errors. A potential solution for the problem is proposed to replace the single rotating mirror with two co-rotating mirrors. The use of two co-rotating mirrors reduces the image biasing with desired amounts of the velocity shift available, and, at the same time, makes the image biasing uniform on the entire image field so that analytical corrections for the biasing are readily feasible. Detailed imaging kinematics of the suggested method are presented to improve the design of practical PlV systems. Also presented is experimental confirmation of the image correction using two co-rotating mirrors.

more details, click here [1.9MB in PDF]

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