Browsing by Subject "Unsteadiness correction"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Open Access A fast algorithm for subpixel accuracy image stabilization for digital film and video(SPIE, 1998) Eroğlu, Çiğdem; Erdem, A. T.This paper introduces a novel method for subpixel accuracy stabilization of unsteady digital films and video sequences. The proposed method offers a near-closed-form solution to the estimation of the global subpixel displacement between two frames, that causes the misregistration of them. The criterion function used is the mean-squared error over the displaced frames, in which image intensities at subpixel locations are evaluated using bilinear interpolation. The proposed algorithm is both faster and more accurate than the search-based solutions found in the literature. Experimental results demonstrate the superiority of the proposed method to the spatio-temporal differentiation and surface fitting algorithms, as well. Furthermore, the proposed algorithm is designed so that it is insensitive to frame-to-frame intensity variations. It is also possible to estimate any affine motion between two frames by applying the proposed algorithm on three non-collinear points in the unsteady frame.Item Open Access Subpixel accuracy image registration with application to unsteadiness correction(Bilkent University, 1997) Eroğlu, ÇiğdemImage registration refers to the problem of spatially aligning the images in an image sequence. The proposed efficient search method estimates the subpixel displacements causing the misregistration of two frames faster than other methods without any loss in accuuracy. It is assumed that the misregistration is due to global motion. The criterion function used is the mean-squared error over the displaced frames in which image intensities at subpixel locations are evaluated using bilinear interpolation only once in the formula. A novel nearclosed-form solution does not use any search unless absolutely necessary. An extension of the near-closed-form solution that is insensitive to intensity variations between the frames can account for contrast and brightness changes in a sequence. Simulations on unsteady image sequences demonstrate the superiority of the proposed near closed-form solution. The application to de-interlacing also gives good results.