Mat
(Matrix) is an n-dimensional array that can be used to store various type of data, such as RGB, HSV or grayscale images, vectors with real or complex values, other matrices etc.
A Mat
contains the following information: width
, height
, type
, channels
, data
, flags
, datastart
, dataend
and so on.
It has several methods, some of them are: create
, copyTo
, convertTo
, isContinious
etc.
There are many ways to create a Mat variable. Consider I want to create a matrix with 100 rows, 200 columns, type CV_32FC3:
int R = 100, C = 200;
Mat m1; m1.create(R,C,CV_32FC3);//creates empty matrix
Mat m2(cv::Size(R, C), CV_32FC3); // creates a matrix with R rows, C columns with data type T where R and C are integers,
Mat m3(R,C,CV_32FC3); // same as m2
Initializing Mat:
Mat m1 = Mat::zeros(R,C,CV_32FC3); // This initialized to zeros, you can use one, eye or cv::randn etc.
Mat m2(R,C,CV_32FC3);
for (int i = 0; i < m2.rows; i++)
for (int j = 0; j < m2.cols; j++)
for (int k = 0; k < m2.channels(); k++)
m2.at<Vec3f>(i,j)[k] = 0;
//Note that, because m2 is a float type and has 3 channels, we used Vec3f, for more info see Vec
Mat m3(3, out, CV_32FC1, cv::Scalar(0));