Patent ID: 6970577
Filing Date: 2005-11-29
Classification: G06K,G06T

Abstract:
1. A method for tracking an object in an image using Fast Fourier Transforms, comprising: identifying a background correction term for a Fast Fourier Transform correlation tracker; and tracking the object based on a representation of the background correction term that includes a frequency domain sinc function; wherein the tracking includes zero-padding a reference window to a size of a search window, performing a 2 dimension Fast Fourier Transform of the zero-padded reference window into the frequency domain, and taking a complex conjugate of the transformed zero-padded reference window, performing a 2 dimension Fast Fourier Transform of a search window, performing a complex multiplication of the complex conjugate of the transformed zero-padded reference window and the transformed search window, and multiplying the result by a first factor to obtain a first result in the frequency domain, squaring pixel values of the search window and performing a 2 dimension Fast Fourier Transform of the squared pixel values into the frequency domain, multiplying the transform of the squared pixel values with a sinc function to obtain a second result in the frequency domain, summing the first and second results to form a third result in the frequency domain, performing a 2 dimension inverse Fast Fourier Transform of the third result to obtain a spatial-domain correlation surface, and searching for a minimum of the correlation surface.