Patent ID: 7555169

Claim:
A method for reducing image noise, comprising: selecting a first image of 2 n ×2 n pixels, wherein n is a positive integer value; transforming the first image into a first frequency spectrum by applying a Fourier transform, wherein each pixel of the first frequency spectrum has a real part X and a imaginary part Y; calculating a first energy of each pixel of the first frequency spectrum and a first mean energy of all pixels of the first frequency spectrum; calculating a first mean value and a first standard deviation of the real part of the pixels of the first frequency spectrum; calculating a second mean value and a second standard deviation of the imaginary part of the pixels of the first frequency spectrum; determining a first predetermined value and a second predetermined value; and executing a noise elimination procedure, wherein when the first energy of the pixel exceed the first mean energy, replacing the real part X of the pixel with the first predetermined value and replacing the imaginary part Y of the pixel with the second predetermined value; when the first energy of the pixel does not exceed the first mean energy, the real part X and the imaginary part Y of the pixel are reserved.