cv::threshold()

double cv::threshold(
    cv::InputArray src, // 輸入影象
    cv::OutputArray dst, // 輸出影象
    double thresh, // 閾值
    double maxValue, // 向上最大值
    int thresholdType // 閾值化操作的型別 
)

#include "opencv2/opencv.hpp"
#include <iostream>

using namespace std;
using namespace cv;

int main()
{
        Mat srcImage = imread("D:\\cpp_practice\\lena_gray.tif"
 
);
        imshow("原圖", srcImage);
        if (!srcImage.data)
        {
            cout << "fail to load image" << endl;
            return 0;
        }

        Mat dstImage1,dstImage2,dstImage3,dstImage4;
        double thresh = 100;
        int maxVal = 255;

        cv::threshold(srcImage, dstImage1, thresh, maxVal, cv::THRESH_BINARY);
        imshow("THRESH_BINARY"
 
, dstImage1);

        cv::threshold(srcImage, dstImage2, thresh, maxVal, cv::THRESH_BINARY_INV);
        imshow("THRESH_BINARY_INV", dstImage2);

        cv::threshold(srcImage, dstImage3, thresh, maxVal, cv::THRESH_TRUNC);
        imshow("THRESH_TRUNC", dstImage3);

        cv::threshold(srcImage, dstImage4, thresh, 150
 
, cv::THRESH_TOZERO);
        imshow("THRESH_TOZERO", dstImage4);


        cout << dstImage1 << endl;

        waitKey(0);
        return 0;
    }

opencv3 大津法ostu