How to make an image black and white in opencv c++?

Question

Actually I'm a complete beginner in opencv and in native C++ concepts so please excuse me if my question is so simple. Basically I want to convert an image to Black&White by using native C++ for that I tried to find tutorials but I couldn't find any. Thus can anyone please help me to learn this concept ?

Answer 1

cv::Mat colorMat, grayscaleMat, binaryMat;

First convert to grayscale:

cv::cvtColor(colorMat, grayscaleMat, CV_BGR2GRAY);

Then apply a binary threshold to the grayscale image:

cv::threshold(grayscaleMat, binaryMat, 100, 255, cv::THRESH_BINARY);

Also, you may want to consider using the OpenCV4Android SDK .

Answer 2

You should use the cvtColor function. Lets say 'image' is your original photo, and 'gray_image' is the variable where you will store your new gray photo:

cvtColor( image, gray_image, CV_BGR2GRAY );

('image' & 'gray_image' are 'Mat' type)