香港中文大学：Image processing and computer vision（PPT课件讲稿）Edge detection and image filtering

Steps continue Step 5 ●Step7: C(0,1) C(2,1) =1x1+1*2 1121 ·=-1*4+1*1+1*5+1*3 3 5 1·Step8: Step 6 3·C(3,1) 14 ●C(1,1) 1*1+1*3 =-1*1+1*4+1*2+1*5 2 =10 C(m,n/C(0,2) c(1,2) C(2,2) c(32) C(01)=3C(1,1)=10C(2,1)=5C(3,1)=2 C(0,0)=2c(10)=3C(2,0)=2C(3,0)=3 Tutorial for CMSC5711: Edge vo. 1a

Steps continue • Step 5: • C(0,1) • =1x1+1*2 • =3 • Step 6: • C(1,1) • = -1*1+1*4+1*2+1*5 • =10 • Step 7: • C(2,1) • = -1*4+1*1+1*5+1*3 • =5 • Step 8: • C(3,1) • = -1*1+1*3 • =2 1 4 1 2 5 3 -1 1 1 1 1 4 1 2 5 3 -1 1 1 1 1 4 1 2 5 3 -1 1 1 1 1 4 1 2 5 3 -1 1 1 1 C(m,n)= C(0,2) C(1,2) C(2,2) C(3,2) C(0,1)=3 C(1,1)=10 C(2,1)=5 C(3,1)=2 C(0,0)=2 C(1,0)=3 C(2,0)=-2 C(3,0)=-3 Tutorial for CMSC5711 : Edge v0.1a 26

Find all elements in C for all possible c(m=0,n=0)=2, c(m=1,n=0)=-2+5=3, c(m=1,n=1)=10, etc C(m, n) 2 155 h=C=31052 23-2-3 Tutorial for CMSC5711: Edge vo. 1a

Find all elements in C for all possible m,n ( 0, 0) 2, ( 1, 0) 2 5 3, ( 1, 1) 10, ,...., . 1 5 5 1 * [] 3 10 5 2 2 3 2 3 c m n c m n c m n etc I h c = = = = = = − + = = = =     = =       − − m n m n C(m,n) Tutorial for CMSC5711 : Edge v0.1a 27

Worksheet 3.1 |=[141; 253 351] h2=[-11 Find convolution of i and h2 Tutorial for CMSC5711: Edge vo. 1a

Worksheet 3.1 • I=[1 4 1; • 2 5 3 • 3 5 1] • h2=[-1 1 • 1 -1] • Find convolution of I and h2. Tutorial for CMSC5711 : Edge v0.1a 28

Answer ws/ 3 1 ‰Ws3.1edge =[141; 253 351 h2=[-11 1-1] %Find convolution of i and h2 conv(, h2) ans= % -10-12 -112-2 32-4-1 Tutorial for CMSC5711: Edge vo. 1a

Answer ws5711_3_1 • %ws3.1 edge • I=[1 4 1; • 2 5 3 • 3 5 1] • h2=[-1 1 • 1 -1] • %Find convolution of I and h2. • conv2(I,h2) • % • % ans = • % • % -1 -3 3 1 • % -1 0 -1 2 • % -1 1 2 -2 • % 3 2 -4 -1 Tutorial for CMSC5711 : Edge v0.1a 29

Worksheet 3. 2: Find edge image using filter masks h a and h b 0000 00 000 Horizontal edge mask 00 0 00 0000 Vertical edge mask Tutorial for CMSC5711: Edge vo. 1a

Worksheet 3.2: Find edge image using filter masks h_A and h_B • Horizontal edge mask Vertical edge mask           − =           = −             = 0 1 0 0 0 0 0 1 0 _ 0 0 0 1 0 1 0 0 0 _ 0 0 1 1 0 0 1 1 0 0 0 0 0 0 0 0 h y h x I Tutorial for CMSC5711 : Edge v0.1a 30