更改图像的亮度和对比度

Posted 2023-02-22

【中文标题】更改图像的亮度和对比度

【英文标题】：Changing brightness and contrast of an image

【发布时间】：2013-05-20 09:26:41

【问题描述】：

我正在编写以下代码

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

using namespace std;
using namespace cv;

Mat change(Mat m);

int main()


    Mat image = imread("C:/Users/Public/Pictures/Sample Pictures/Penguins.jpg");

    Mat copy = Mat::zeros(image.size(),image.type());

    Mat changedImage = change(copy);

    namedWindow("Image");
    imshow("Image",changedImage);

    waitKey(0);


Mat change(Mat m)

    int cols = m.cols;
    int rows = m.rows;

    double alpha = 2.2;
    int beta = 50;


    for(int i=0;i<rows;i++)
    
        for(int c=0;c<cols;c++)
        
            m.at<Vec3b>(rows,c)[0] = saturate_cast<uchar>(alpha* (m.at<Vec3b>(rows,cols)[0]) + beta);
            m.at<Vec3b>(rows,c)[1] = saturate_cast<uchar>(alpha* (m.at<Vec3b>(rows,cols)[1]) + beta);
            m.at<Vec3b>(rows,c)[2] = saturate_cast<uchar>(alpha* (m.at<Vec3b>(rows,cols)[2]) + beta);
        
    

    return m;

这编译得很好，但是当我运行它时，我得到了以下错误

    OpenCV Error: Assertion failed (dims <= 2 && data && (unsigned)i0 < (unsigned)si
ze.p[0] && (unsigned)(i1*DataType<_Tp>::channels) < (unsigned)(size.p[1]*channel
s()) && ((((sizeof(size_t)<<28)|0x8442211) >> ((DataType<_Tp>::depth) & ((1 << 3
) - 1))*4) & 15) == elemSize1()) in unknown function, file c:\opencv\build\inclu
de\opencv2\core\mat.hpp, line 534

为什么我会得到这个？我想我所做的一切都是正确的。

【问题讨论】：

嗨，为什么不在这个问题中使用矩阵算术运算符：[***.com/questions/16473695/…

changedimage=(2.2*image)+cvScalar(50,50,50);

【参考方案1】：

试试这个代码。

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

using namespace std;
using namespace cv;

Mat change(Mat m);

int main()

    Mat image = imread("C:/Users/Public/Pictures/Sample Pictures/Penguins.jpg");

    Mat changedImage = change(image); //Modified

    namedWindow("Image");
    imshow("Image",changedImage);

    waitKey(0);


Mat change(Mat m)

    int cols = m.cols;
    int rows = m.rows;

    double alpha = 2.2;
    int beta = 50;

    for(int i=0;i<rows;i++)
    
        for(int c=0;c<cols;c++)
        
            m.at<Vec3b>(i,c)[0] = saturate_cast<uchar>(alpha* (m.at<Vec3b>(i,c))[0]) + beta);  //Modified
            m.at<Vec3b>(i,c)[1] = saturate_cast<uchar>(alpha* (m.at<Vec3b>(i,c))[1]) + beta);  //Modified
            m.at<Vec3b>(i,c)[2] = saturate_cast<uchar>(alpha* (m.at<Vec3b>(i,c))[2]) + beta);  //Modified
        
    

    return m;

【参考方案2】：

试试这个...

Mat Change(Mat input,int beta = 50)

Mat Output;

Scalar S(beta,beta,beta);
cv::add(input,S,Output);

return Output;