function?outval?=?edge_intensity（img）?
%?OUTVAL?=?EDGE_INTENSITY（IMG）?
?
if?nargin?==?1?
????img?=?double（img）;?
????%?Create?horizontal?sobel?matrix?
????w?=?fspecial（‘sobel‘）;?
?????
????%?Get?the?size?of?img?
????[r?c?k]?=?size（img）;?
?????
????gx?=?imfilter（imgw‘replicate‘）;?
????gy?=?imfilter