Logo Questions Linux Laravel Mysql Ubuntu Git Menu
 

OpenCV rgb value for cv::Point in cv::Mat

Tags:

c++

opencv

I've looked at different questions already here on StackOverflow, but none seems to helps. What I want to do is quite simple: I have a cv::Point and I need to get the RGB value for the pixel at that point in a cv::Mat so that I can compare it with a stored RGB value.

Now this should be very easy but I've tried 1001 different ways and it just doesnt work for me.

Someone please help me out of my misery!!

edit: both answers below work! I'm kinda new with C++ and didn't know that outputting a unsigned char through cout gives a questionmark! printf offcourse gives the right value!!

like image 652
user458753 Avatar asked Jan 20 '23 16:01

user458753


1 Answers

That's really easy. However the documentation of OpenCV is good at hiding the simple answers.

Here is example code:

cv::Mat3b image = imread(filename);
cv::Point point(23, 42);
cv::Vec3b template;
template[0] = 128; template[1] = 12; template[2] = 64;

const cv::Vec3b& bgr = image(point);
if (bgr[0] == template[0] && bgr[1] == template[1] && bgr[2] == template[2])
   std::cout << "Colors match!" << std::endl;

There are probable better ways of dealing with the cv::Vec, but I forgot. See also the OpenCV Cheat Sheet.

like image 70
ypnos Avatar answered Jan 31 '23 09:01

ypnos