OpenCV threshold operation

learning address

#include <iostream>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/opencv.hpp>

using namespace std;
using namespace cv;

// image threshold threshold
// 1. Binarize threshold binary
// greater than the threshold equal to 255 (white) less than the threshold equal to 0 (black) (when the threshold is 0, it is all white; when the threshold is 255, the original black)
// 2. Threshold binary inverted
// greater than the threshold equal to 0 (black) less than the threshold equal to 255 (white) (when the threshold is 0, all black; when the threshold is 255, all white)
// 3. Truncate truncate
// Greater than the threshold equal to the threshold less than the threshold unchanged (when the threshold is 0, it is completely black; when the threshold is 255, the original image)
// 4. threshold to zero
// Greater than the threshold and unchanged less than the threshold equal to 0 (black) (when the threshold is 0, the original image; when the threshold is 255, it is all black)
// 5. Threshold to zero inverted
// greater than the threshold equal to 0 (black) less than the threshold unchanged (when the threshold is 0, it is completely black; when the threshold is 255, the original image)

// THRESH_OTSU THRESH_TRIANGLE automatically find the threshold


Mat src1, src2, gray_src, dst;
int threshold_value = 127;
int threshold_max = 255;
int type_value = 0;
int type_max = 4;

void Threshold_Demo(int, void*) {
    threshold(gray_src, dst, threshold_value, threshold_max, type_value);
    imshow("Threshold Demo", dst);
}



int main() {
    
    src1 = imread("/Users/apple/Desktop/fapiao.jpg", IMREAD_COLOR);
    //src2 = imread("/Users/apple/Desktop/test2.jpg", IMREAD_COLOR);
    if (src1.empty()) { // if (!src.data())
        cout << "could not load image..." << endl;
        return -1;
    }
    //imshow("input", src1);
    
    
    
    cvtColor(src1, gray_src, CV_BGR2GRAY);
    
    namedWindow("Threshold Demo", WINDOW_AUTOSIZE);
    imshow("Threshold Demo", gray_src);
    createTrackbar("Threshold Value: ", "Threshold Demo", &threshold_value, threshold_max, Threshold_Demo);
    createTrackbar("Type Value: ", "Threshold Demo", &type_value, type_max, Threshold_Demo);
    Threshold_Demo(0 , 0);
    
    waitKey(0);
    
    return 0;
}