如果你想提升一幅圖像的亮度，可以給每個像素的值都加上一個正的常數

\[ new\_image (i, j) = image(i, j) + c \]

如果你想降低一幅圖像的亮度，可以給每個像素的值都減去一個正的常數

\[ new\_image (i, j) = image(i, j) - c \]

Code

/* 作者：鄭大峰 時間：2019年09月20日 環境：OpenCV 4.1.1 + VS2017 內容：Change Brightness */#include "pch.h" #include <iostream> #include <opencv2/opencv.hpp>using namespace std; using namespace cv;int main() {Mat image = imread("claudia.png");if (image.empty()){cout << "Could not open or find the image" << endl;cin.get();return -1;}Mat imageBrighnessHigh50;image.convertTo(imageBrighnessHigh50, -1, 1, 50); //increase the brightness by 50Mat imageBrighnessHigh100;image.convertTo(imageBrighnessHigh100, -1, 1, 100); //increase the brightness by 100Mat imageBrighnessLow50;image.convertTo(imageBrighnessLow50, -1, 1, -50); //decrease the brightness by 50Mat imageBrighnessLow100;image.convertTo(imageBrighnessLow100, -1, 1, -100); //decrease the brightness by 100//Defining window names for above imagesString windowNameOriginalImage = "Original Image";String windowNameBrightnessHigh50 = "Brightness Increased by 50";String windowNameWithBrightnessHigh100 = "Brightness Increased by 100";String windowNameBrightnessLow50 = "Brightness Decreased by 50";String windowNameBrightnessLow100 = "Brightness Decreased by 100";//Create and open windows for above imagesnamedWindow(windowNameOriginalImage, WINDOW_NORMAL);namedWindow(windowNameBrightnessHigh50, WINDOW_NORMAL);namedWindow(windowNameWithBrightnessHigh100, WINDOW_NORMAL);namedWindow(windowNameBrightnessLow50, WINDOW_NORMAL);namedWindow(windowNameBrightnessLow100, WINDOW_NORMAL);//Show above images inside the created windows.imshow(windowNameOriginalImage, image);imshow(windowNameBrightnessHigh50, imageBrighnessHigh50);imshow(windowNameWithBrightnessHigh100, imageBrighnessHigh100);imshow(windowNameBrightnessLow50, imageBrighnessLow50);imshow(windowNameBrightnessLow100, imageBrighnessLow100);waitKey(0); // Wait for any key strokedestroyAllWindows(); //destroy all open windowsreturn 0; }

Result

Explanation

void Mat::convertTo( OutputArray m, int rtype, double alpha=1, double beta=0 ) const

This function converts the each pixel value to the target data type and changes the value as per the following formula. pixel_value_of_output_image(x, y) = pixel_value_of_input_image(x, y) * alpha + beta;

m - Output image. This data structure will be reallocated if required.

rtype - Type of the output image. If rtype is a negative value, the type of the output image will be same as the input image.

alpha - Each pixels in the input image will be multiplied by this number before assigning to the output image.

beta - This value will be added to each pixels in the input image and assigned to the output image.

轉載于:https://www.cnblogs.com/zdfffg/p/11558123.html

總結

以上是生活随笔為你收集整理的OpenCV C++ 04 - Change Brightness的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。