Understanding Spatial Frequency of Images (using matlab)
If it is the repetitive pattern, you may observe some strong magnitude at some position in frequency domain. Use imagesc(abs(fftshift(fft2(img)))), you probably would see:



Those small white spots in the image correspond to the repetitive texture that is superimposed on the image. You may then use ordfilt2(F,roi^2,ones(roi)) to find out the roi * roi local maximum of the image. Here F = abs(fftshift(fft2(img))), roi is the region size of interest. Then change those values to zero:



With the real(ifft2(fftshift(F0))) you will recover the image in spatial domain. F0 is the frequency distribution after you implement the white spots removal on  fftshift(fft2(img)))