> (define bush128 (read-image "bush128.pgm")) > bush128 #<image: rows = 128 cols = 128> > > (define ilp (ideal-lowpass 128 16.0)) > ilp #<image: rows = 128 cols = 128> > > (real-part (ifft (* (fft bush128) ilp)))) #<image: rows = 128 cols = 128> > > (define glp (gaussian-lowpass 128 32.0)) > glp #<image: rows = 128 cols = 128> > > (real-part (ifft (* (fft bush128) glp)))) #<image: rows = 128 cols = 128> > > (define ibp (ideal-bandpass 128 32.0 16.0)) > ibp #<image: rows = 128 cols = 128> > > (real-part (ifft (* (fft bush128) ibp)))) #<image: rows = 128 cols = 128> > > (define gbp (gaussian-bandpass 128 32.0 16.0)) > gbp #<image: rows = 128 cols = 128> > > (real-part (ifft (* (fft bush128) gbp)))) #<image: rows = 128 cols = 128> >