Scharr edge detection

Scharr edge detection

Hi.

The wikipedia article on the Sobel operator mentions that it does not have 
perfect rotational symmetry and that Scharr improved that by coming up with 
a new kernel (no citations given). Does anyone know the name of the article 
in which  Scharr addresses this matter?

Thanks in advance! 

Re: Scharr edge detection

hi,

not sure, if we are speaking about the same person, but
there is a  dissertation (in german) about 'optimal filters in vision'.
give it a try:

http://deposit.d-nb.de/cgi-bin/dokserv?idn=961535989&dok_var=d1&dok_ext=pdf&filename=961535989.pdf

cheers

Edward Jensen schrieb:
> Hi.
> 
> The wikipedia article on the Sobel operator mentions that it does not have 
> perfect rotational symmetry and that Scharr improved that by coming up with 
> a new kernel (no citations given). Does anyone know the name of the article 
> in which  Scharr addresses this matter?
> 
> Thanks in advance! 
> 
>