This paper focuses on the correlation of two successive scalar images for the purpose of measuring imaged fluid motions. A method is presented for deforming, or transforming, one image to another. Taylor series expansions of the Lagrangian displacement field are used, in conjunction with an integral form of the equations of motion, to approximate this transformation. The proposed method locally correlates images for displacements, rotations, deformations, and higher order displacement gradient fields, and applies a global minimization procedure to insure a global consistency in the results. An integral form of the equations of motion is employed and, as a consequence, no explicit spatial or temporal differentiation of the image data is required in estimating the displacement field. As a consequence, this method is appropriate for both continuous scalar as well as discrete particle image data. Successive two-dimensional digital CCD images of fluid motion marked with dye, are used to verify the capabilities of the method. The utility of the method is also illustrated using a pair of Voyager 2 images of Jupiter.

© 1992, 1993 Phillip T. Tokumaru and Paul E. Dimotakis. GALCIT Report FM92-1a Updated: 21 December 1993. We would like to acknowledge the support of this effort by AFOSR Grant Nos. 90-0304 and F49620-92-5-0290, and a joint contract with M. Gharib by DARPA/Navy Grant No. N00014-91-J-1968, We would also like to acknowledge the many contributions by Dan Lang in the development and integration of the image-data acquisition systems employed in these investigations. Finally, we would like to thank Stewart (Andy) Collins and the Detector Advanced Development group of the Imaging Systems Section, at JPL, for their collaboration.

Submitted - FM92-1a.pdf