clear?all;
a=imread（‘C:\Users\Administrator\Desktop\1.bmp‘）;
for?k=1:1000
????i=fix（rand*250）;
????j=fix（rand*250）;
????x（k）=a（i+1j+1）;
????y（k）=a（i+1j+2）;
end
sum=0.0;
sum=double（sum）;
for?i=1:1000
????sum=sum+double（x（i））;
end
ex=sum/1000;
sum=0.0;
sum=double（sum）;
for?i=1:1000
????sum=sum+double（y（i））;
end
ey=sum/1000;
sum=0.0;
sum=double（sum）;
for?i=1:1000
????sum=sum+double（x（i））*double（x（i））;