§4.8.3高斯低通滤波器(Gaussian Lowpass Filters) Example 1:Gaussian lowpass filtering ☒ ☒ -D2(u,v) D0=5 D0=15 H(u,v)=e 202 ●●● O aaaaaa No ringing at all ■ ☒ ■■☒ ·因■☒■☒ D0=30 D0=80 D0=230 ●●● aaaa a aa aaa aaaa aa The filtered image can have no negative values Example 1: Gaussian lowpass filtering The filtered image can have no negative values §4.8.3 高斯低通滤波器 (Gaussian Lowpass Filters) 2 2 ( , ) 2 ( , ) D u v H u v e    No ringing at all 𝑫𝟎 = 𝟓 𝑫𝟎 = 1𝟓 𝑫𝟎 = 30 𝑫𝟎 = 𝟖0 𝑫𝟎 = 𝟐𝟑0