2A-L6

2A-L6 Edge detection:
2D operators
CS4495/6495
Introduction to Computer Vision

Derivative theorem of convolution - 1D
•This saves us one operation:
) ( )(
xx
h f h f
f
h
xh
()
xhf

Derivative of Gaussian filter – 2D
( ) ( )
xx
I g h I g h    

Derivative of Gaussian filter – 2D
11  
0.0030 0.0133 0.0219 0.0133 0.0030
0.0133 0.0596 0.0983 0.0596 0.0133
0.0219 0.0983 0.1621 0.0983 0.0219
0.0133 0.0596 0.0983 0.0596 0.0133
0.0030 0.0133 0.0219 0.0133 0.0030
( ) ( )
xx
I g h I g h    

Derivative of Gaussian filter – 2D
11  
0.0030 0.0133 0.0219 0.0133 0.0030
0.0133 0.0596 0.0983 0.0596 0.0133
0.0219 0.0983 0.1621 0.0983 0.0219
0.0133 0.0596 0.0983 0.0596 0.0133
0.0030 0.0133 0.0219 0.0133 0.0030
( ) ( )I g h I g h    
Is this preferable?