Patent ID: 6701029
Filing Date: 2004-03-02
Classification: G06K

Abstract:
A method of calculating ring-wedge data from a digital image comprising the step of performing a discrete Fourier transform of the digital image, wherein the ring-wedge data are segmented into a plurality of unsegmented semi-circular annular rings and a plurality of unsegmented pie-shaped wedges, and wherein the performing step comprises calculating mj=&Sum;u=0N-1&it;â€ƒ&it;&Sum;v=0M-1&it;â€ƒ&it;&LeftBracketingBar;F~&it;â€ƒ&it;(u,v)&RightBracketingBar;&it;â€ƒ&it;M~j&it;â€ƒ&it;(u,v),where mj is a jth measurement over a sampling area to which each pixel's degree of membership is given by {tilde over (M)}j(u,v), F~&it;â€ƒ&it;(u,v)=&Sum;n=0N-1&it;â€ƒ&it;&Sum;m=0M-1&it;â€ƒ&it;f&it;â€ƒ&it;(n,m)&it;â€ƒ&it;exp&af;[-2&it;â€ƒ&it;Ï€&it;â€ƒ&it;(unN+vmM)],and where f(n,m) comprises digital image pixel values with 0&lE;n