Opencv sum()[]

xiaojidan
1 ●1 ●2

I am new to opencv , I do not understand the function "sum".

Mat img=(Mat_<double>(3,3)<<0,-1,0,-1,5,-1,2,-1,0); double rr=sum(img)[0]; cout<<"rr"<<rr<<endl;< p="">

waitKey(0);
return 0;

What is the meaning of this function "sum", sum(img)[0] is standing for?? sum(img)[1] is standing for ? sum(img)[2] is stranding for??

1 answer

berak
32993 ●7 ●81 ●312

sum() returns a Scalar with the sum of all pixels per channel

so, for a 3channel img (think a color image),

Scalar s = sum(img);
// s[0] is the sum of the 1st channel (B probably)
// s[1] is the sum of the 2nd channel (G probably)
// s[2] ...

in your case, the Mat only has one channel, so double s = sum(mat)[0] is the way to access it.

Thank you

xiaojidan ( 2013-06-05 06:29:20 -0600 )edit

Asked: 2013-06-04 22:14:02 -0600

Seen: 4,024 times

Last updated: Jun 05 '13