目標(biāo)
熟悉OPENCV如何存儲及處理圖像。
Mat
Mat由2部分組成：矩陣頭和指向矩陣值的指針
Mat A, C; // creates just the header parts
A = imread(argv[1], IMREAD_COLOR); // here we'll know the method used (allocate matrix)
Mat B(A); // Use the copy constructor
C = A; // Assignment operator
Mat D (A, Rect(10, 10, 100, 100) ); // using a rectangle
Mat E = A(Range::all(), Range(1,3)); // using row and column boundaries
上述只是復(fù)制矩陣頭和指向數(shù)據(jù)矩陣的指針髓堪。如果想要復(fù)制數(shù)據(jù)，可以
Mat F = A.clone();
Mat G;
A.copyTo(G);
Storing methods
灰度和彩色猪叙。他們的數(shù)據(jù)類型不同恐锣。
- RGB is the most common as our eyes use something similar, however keep in mind that OpenCV standard display system composes colors using the BGR color space (a switch of the red and blue channel).
- The HSV and HLS decompose colors into their hue, saturation and value/luminance components, which is a more natural way for us to describe colors. You might, for example, dismiss the last component, making your algorithm less sensible to the light conditions of the input image.
- YCrCb is used by the popular JPEG image format.
Creating a Mat object explicitly
Mat M(2,2, CV_8UC3, Scalar(0,0,255));
cout << "M = " << endl << " " << M << endl << endl;
int sz[3] = {2,2,2};
Mat L(3,sz, CV_8UC(1), Scalar::all(0));
M.create(4,4, CV_8UC(2));
cout << "M = "<< endl << " " << M << endl << endl;
Mat E = Mat::eye(4, 4, CV_64F);
Mat O = Mat::ones(2, 2, CV_32F);
Mat Z = Mat::zeros(3,3, CV_8UC1);
Mat C = (Mat_<double>(3,3) << 0, -1, 0, -1, 5, -1, 0, -1, 0);
Mat R = Mat(3, 2, CV_8UC3);
randu(R, Scalar::all(0), Scalar::all(255)); //隨機(jī)初始值，只需要確定上下界
其他常見類型輸出
Point2f P(5, 1);
Point3f P3f(2, 6, 7);
vector<float> v;
v.push_back( (float)CV_PI); v.push_back(2); v.push_back(3.01f);
vector<Point2f> vPoints(20);
for (size_t i = 0; i < vPoints.size(); ++i)
vPoints[i] = Point2f((float)(i * 5), (float)(i % 7));
