FLUID SURFACE IMAGING USING MICROLENS ARRAYS

The paper describes a new technique for measuring surface slopes at th e air-water interface. A microlens array is employed to optically samp le the fluid surface at a large number of measurement points in parall el. The focal plane image of the lenslet array is recorded by a standa rd video camera, generating a data set of typically 4000 candidate sam ples for each video frame. The displacement of the focal spots is anal yzed using a cross-correlation technique augmented by a topological id entification algorithm which makes use of the hexagonal structure of t he lenslet array. Surface height profiles are computed by integrating the surface slope field.