opencv学习之路（9）、对比度亮度调整与通道分离

一、对比度亮度调整

#include<opencv2/opencv.hpp>
using namespace cv;

#define WIN_NAME "输出图像"
Mat src,dst;
int contrast=20,bright=20;

void onChange(int,void*){
    for (int i = 0; i < src.rows; i++)
    {
        for (int j = 0; j < src.cols; j++)
        {
            //saturate_cast<uchar>    溢出保护：if(data<0) data=0;    if(data>255) data=255;
            dst.at<Vec3b>(i,j)[0]=saturate_cast<uchar>(src.at<Vec3b>(i,j)[0]*contrast*0.01+bright);
            dst.at<Vec3b>(i,j)[1]=saturate_cast<uchar>(src.at<Vec3b>(i,j)[1]*contrast*0.01+bright);
            dst.at<Vec3b>(i,j)[2]=saturate_cast<uchar>(src.at<Vec3b>(i,j)[2]*contrast*0.01+bright);
        }
    }
    imshow("原图",src);
    imshow(WIN_NAME,dst);
}

void main(){
    src=imread("E://1.jpg");
    dst=Mat::zeros(src.size(),src.type());
    //Mat::zeros();//将矩阵元素置为0
    //Mat::ones();//置1
    namedWindow(WIN_NAME,CV_WINDOW_AUTOSIZE);
    createTrackbar("对比度",WIN_NAME,&contrast,300,onChange,0);
    createTrackbar("亮  度",WIN_NAME,&bright,200,onChange,0);

    onChange(contrast,0);//回调函数初始化
    onChange(bright,0);

    waitKey(0);

}

二、通道分离与合并

#include<opencv2/opencv.hpp>
using namespace cv;

void main(){
    Mat img=imread("E://2.jpg");
    Mat dst;
    vector<Mat>channels;//定义Mat类型的向量

    split(img,channels);//通道分离
    Mat blue=channels.at(0);
    Mat green=channels.at(1);
    Mat red=channels.at(2);

    threshold(blue,blue,200,255,THRESH_BINARY);//二值化：大于200的赋值255，小于200的赋值0
    threshold(green,green,200,255,THRESH_BINARY);
    threshold(red,red,200,255,THRESH_BINARY);

    merge(channels,dst);//通道合并

    imshow("原图",img);
    imshow("blue",blue);
    imshow("green",green);
    imshow("red",red);
    imshow("dst",dst);
    waitKey(0);
}