opencv :: contours find (find contour in your image)

 

Profile found (find contour)
Profile found is to find an object's outline basic image edge extraction based methods.
Therefore, the threshold value of the selected edge extraction will affect the final outline findings

 

 

// find the profile 
cv :: findContours (
    BINIMG InputOutputArray,          // the input image, the pixel is regarded as non-zero pixel values remain unchanged 1,0, 'bit. 8- 
    OutputArrayOfArrays Contours,     // entire contour of the object found 
    outputArray, hierachy             // view of the topology, can be selected, the profile discovery algorithm is the image topology implementation. 
    int MODE,                          // Contour mode 
    int Method,                         // discovery method 
    Point Point offset = ()             // displacement contour pixel, the default (0, 0) no displacement 
)

// Draw the outline 
drawContours (
    BINIMG InputOutputArray,          // output image 
    OutputArrayOfArrays Contours,     //   entire contour of the object found 
    Int contourIdx                     // contour index 
    const the Scalar & Color,             // when rendering color 
    int   Thickness,                     // draw a line width 
    int   lineType,                     // the type of line LINE_8 
    InputArray Hierarchy,             // topology 
    int maxLevel,                     // maximum number of layers, the current drawn 0, 1 represents a drawing and drawing current contour embedded 
    Point Point offset = ()             // contour displacement, optionally 
}

 

 

Mat src, dst;
int threshold_value = 100;
int threshold_max = 255;
RNG rng;
void Demo_Contours(int, void*);
int main(int argc, char** argv) {
    src = imread(STRPAHT);
    if (src.empty()) {
        printf("could not load image...\n");
        return -1;
    }

    cvtColor(src, src, CV_BGR2GRAY);
    createTrackbar("Threshold Value:", "findcontours - demo", &threshold_value, threshold_max, Demo_Contours);
    Demo_Contours(0, 0);

    waitKey(0);
    return 0;
}

void Demo_Contours(int, void*) {
    Mat canny_output;
    vector<vector<Point>> contours;
    vector<Vec4i> hierachy;
    Canny(src, canny_output, threshold_value, threshold_value * 2, 3, false);
　　 //发现
    findContours(canny_output, contours, hierachy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point(0, 0));

    dst = Mat::zeros(src.size(), CV_8UC3);
    RNG rng(12345);
    for (size_t i = 0; i < contours.size(); i++) {
        Scalar color = Scalar(rng.uniform(0, 255), rng.uniform(0, 255), rng.uniform(0, 255));
　　　　  //绘制
        drawContours(dst, contours, i, color, 2, 8, hierachy, 0, Point(0, 0));
    }
    imshow("output_win", dst);
}