OpenCV项目(18)|图像对比度亮度调整

#include "opencv2/core/utility.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/imgcodecs.hpp"
#include "opencv2/highgui.hpp"

#include <iostream>

using namespace cv;
using namespace std;

Mat srcImage, dstImage;
int g_nContrast, g_nBrightness;
int g_nMaxContrast = 300;
int g_nMaxBrightness = 200;
void on_BrightnessAndContrast(int, void*)
{
  for (int i = 0; i < srcImage.rows; i++)
    for (int j = 0; j < srcImage.cols; j++)
      for (int c = 0; c < srcImage.channels(); c++)
      {
        dstImage.at<Vec3b>(i, j)[c] = saturate_cast<uchar>((g_nContrast * 0.01) * (srcImage.at<Vec3b>(i, j)[c]) + g_nBrightness);
      }
 
  
  imshow("yuan", srcImage);
  imshow("xiaoguo", dstImage);
}

int _brightness = 100;//亮度值
int _contrast = 100;//对比度值
Mat image;
//调节图片对比度和亮度
static void updateBrightnessContrast( int /*arg*/, void* )
{
    int histSize = 64;
    //对比度和亮度的初始值
    int brightness = _brightness - 100;
    int contrast = _contrast - 100;

    /*
     * The algorithm is by Werner D. Streidt
     * (http://visca.com/ffactory/archives/5-99/msg00021.html)
     */
    double a, b;
    if( contrast > 0 )
    {
        double delta = 127.*contrast/100;
        a = 255./(255. - delta*2);
        b = a*(brightness - delta);
    }
    else
    {
        double delta = -128.*contrast/100;
        a = (256.-delta*2)/255.;
        b = a*brightness + delta;
    }

    Mat dst, hist;
    //供点算子（像素变换）能力，通过增益（alpha）和偏置（beta）参数对图像进行调整
    image.convertTo(dst, CV_8U, a, b);
    imshow("image", dst);

    calcHist(&dst, 1, 0, Mat(), hist, 1, &histSize, 0);
    Mat histImage = Mat::ones(200, 320, CV_8U)*255;

    normalize(hist, hist, 0, histImage.rows, NORM_MINMAX, CV_32F);

    histImage = Scalar::all(255);
    int binW = cvRound((double)histImage.cols/histSize);

    for( int i = 0; i < histSize; i++ )
        rectangle( histImage, Point(i*binW, histImage.rows),
                   Point((i+1)*binW, histImage.rows - cvRound(hist.at<float>(i))),
                   Scalar::all(0), -1, 8, 0 );
    imshow("histogram", histImage);
}

const char* keys =
{
    "{help h||}{@image|baboon.jpg|input image file}"
};

int main( int argc, const char** argv )
{
    CommandLineParser parser(argc, argv, keys);
    parser.about("\nThis program demonstrates the use of calcHist() -- histogram creation.\n");
    if (parser.has("help"))
    {
        parser.printMessage();
        return 0;
    }

    string inputImage = parser.get<string>(0);
    image = imread(inputImage, IMREAD_GRAYSCALE);
    if(image.empty())
    {
        std::cerr << "Cannot read image file: " << inputImage << std::endl;
        return -1;
    }

    namedWindow("image", 0);
    namedWindow("histogram", 0);
    
    //创建滚动条
    createTrackbar("brightness", "image", &_brightness, 200, updateBrightnessContrast);
    createTrackbar("contrast", "image", &_contrast, 200, updateBrightnessContrast);

    updateBrightnessContrast(0, 0);
    waitKey();


    srcImage = imread("mmmm.jpg");
  dstImage = Mat::zeros(srcImage.size(), srcImage.type());

  namedWindow("xiaoguo", 1);
  createTrackbar("duibi", "xiaoguo", &g_nContrast, g_nMaxContrast, on_BrightnessAndContrast);
  createTrackbar("liangdu", "xiaoguo", &g_nBrightness, g_nMaxBrightness, on_BrightnessAndContrast);
 
  on_BrightnessAndContrast(g_nContrast, 0);
  on_BrightnessAndContrast(g_nBrightness, 0);
  waitKey(0);
    return 0;
}