opencv 彩色图像亮度、对比度调节 直方图均衡化

直接上代码：

#include <Windows.h>
#include <iostream>// for stand I/O
#include <string> // for strings
#include <iomanip> // for controlling float print precision
#include <sstream> // string to number conversion
#include <cmath>
#include <ctype.h>
#include <opencv2/opencv.hpp>

using namespace std;
using namespace cv;

int main()
{
    Mat                m_frame;    
    Mat                m_ycrcb;
    Mat                m_result;
    Mat                m_result2;
    VideoCapture    m_Cap;
    int                m_nWidth = 640;
    int                m_nHeight = 480;

    double alpha = 2.0; /**< Simple contrast control */
    int beta = 0;  /**< Simple brightness control */
    /// Initialize values
    std::cout<<" Basic Linear Transforms "<<std::endl;
    std::cout<<"-------------------------"<<std::endl;
    std::cout<<"* Enter the alpha value [1.0-3.0]: ";std::cin>>alpha;
    std::cout<<"* Enter the beta value [0-100]: "; std::cin>>beta;

    m_Cap.open(0);

    bool bSuccess1 = false,bSuccess2 = false;
    bSuccess1 = m_Cap.set(CV_CAP_PROP_FRAME_WIDTH,m_nWidth);
    bSuccess2 = m_Cap.set(CV_CAP_PROP_FRAME_HEIGHT,m_nHeight);
    if (bSuccess1==false || bSuccess2==false)
    { return -1;}

    m_Cap>>m_frame;
    if (m_frame.empty())
    {
        return -1;
    }

    //用来存储各通道图片的向量
    vector<Mat> splitBGR(m_frame.channels());
    vector<Mat> splitYCrCb(m_frame.channels());

    Mat new_image = Mat::zeros( m_frame.size(), m_frame.type() );

    for (;;)
    {
        m_Cap>>m_frame;
        if (m_frame.empty())
        { return -1;    }

        //方法一：直方图均衡化
        //分割通道，存储到splitBGR中
        split(m_frame,splitBGR);
        //对各个通道分别进行直方图均衡化
        for(int i=0; i<m_frame.channels(); i++)
            equalizeHist(splitBGR[i],splitBGR[i]);
        //合并通道
        merge(splitBGR,m_result);

        //方法二: 直方图均衡化
        //转化为ycrcb
        cvtColor(m_frame,m_ycrcb,CV_BGR2YCrCb);
        split(m_ycrcb,splitYCrCb);
        equalizeHist(splitYCrCb[0],splitYCrCb[0]);
        merge(splitYCrCb,m_ycrcb);
        cvtColor(m_ycrcb,m_result2,CV_YCrCb2BGR);
        

        //方法三:
        //g(i,j) = alpha * f(i,j) + beta
        for( int y = 0; y < m_frame.rows; y++ ) {
            for( int x = 0; x < m_frame.cols; x++ ) {
                for( int c = 0; c < 3; c++ ) {
                    new_image.at<Vec3b>(y,x)[c] =
                        saturate_cast<uchar>( alpha*( m_frame.at<Vec3b>(y,x)[c] ) + beta );
                }
            }
        }

        imshow("原图",m_frame);
        imshow("对比度1",m_result);
        imshow("对比度2",m_result2);
        imshow("对比度3",new_image);

        int c = waitKey(33);
        if (c==27)//ESC退出
        {    break;    }

    }
    
    return 0;
}

参考网址：http://www.opencv.org.cn/opencvdoc/2.3.2/html/doc/tutorials/core/basic_linear_transform/basic_linear_transform.html