电子科线女学光电科学与工程学院 SCHOOL OF OPTOELECTRONIC SCIENCE AND ENGINEERING OF UESTC 1.Image Pyramids a b FIGURE 7.3 Two image pyramids and their histograms: (a)an approximation pyramid; (b)a prediction ◆Guassian Pyramids residual pyramid. →Laplacian Pyramids
1. Image Pyramids Guassian Pyramids Laplacian Pyramids
电子科枝女学光电科学与工程学院 SCHOOL OF OPTOELECTRONIC SCIENCE AND ENGINEERING OF UESTC Laplacian Pyramids Io=Reduce(im),bo=im-Expand(Io) Image -series of images,according to different scales and roughly different energy(freq.)bands
Image series of images, according to different scales and roughly different energy (freq.) bands. I0=Reduce(im), b0=im-Expand(I0 ) Laplacian Pyramids
电子科线女学光电科学与工程学院 SCHOOL OF OPTOELECTRONIC SCIENCE AND ENGINEERING OF UESTC 2.Subband Coding ◆ Subbands In subband coding,an image is decomposed into a set of bandlimited components,called subbands Since the bandwidth of the resulting subbands is smaller than that of the original image,the subbands can be downsampled without loss of information
2. Subband Coding ◆ Subbands Since the bandwidth of the resulting subbands is smaller than that of the original image, the subbands can be downsampled without loss of information. In subband coding, an image is decomposed into a set of bandlimited components, called subbands
电子科发女学光电科学与工程学院 SCHOOL OF OPTOELECTRONIC SCIENCE AND ENGINEERING OF UESTC 2.Subband Coding fn-0) f(n-1) fn-2) f(n-K+1) f(n) Unit Unit Unit delay delay delay order The filtered output h(0) h1) h(2) hK-1) h()f(n) h(1)f(n-1) h(2)fn-2) (-1+1) f(n=∑h(k)f(n-k) fm)=fn★hm) h(0)fm)+h(1)fn-1) =f(n)*h(n) The filter tap h(0)fn)+h(1)f(n-1)+h(2)fn-2 K-1 h(k)fa-k)=fm)★ha k=0 The unit impulse h1) oh(2) h(0) h(K-1) J(n)=Eh(k)5(n-k)=h(n) h3) 0 0 4) Finite impulse response (FIR)filter 1012.. -1012.. .K-1 VWM
( ) ( ) ( ) ( )* ( ) k f n h k f n k f n h n =− = − = ( ) ( ) ( ) ( ) k f n h k n k h n =− = − = 2. Subband Coding ◼ The filtered output ◼ The unit impulse The filter tap order Finite impulse response (FIR) filter
电子科线女学光电科学与工程学院 SCHOOL OF OPTOELECTRONIC SCIENCE AND ENGINEERING OF UESTC 2.Subband Coding h (n) h2(n)=-hn) 1hm)=(-m) 0 0 0 ..-3-2-101234567.. ..-3-2-101234567.+. ..-3-2-101234567.. 贝 i h4(n)=h1(K-1- hs(n)=(-1)h1(n hs(nm=(-1)h1(K-1-n) 0 0 -1 -1 -1 .-3-2-101234567.. .-3-2-101234567.. ..-3-2-101234567.. 2 自 a b c def FIGURE 7.5 Six functionally related filter impulse responses:(a)reference response;(b)sign reversal; (c)and (d)order reversal (differing by the delay introduced);(e)modulation;and (f)order reversal and modulation
2. Subband Coding