[OpenCV] 图像亮度和对比度调整
对比度调整的原理参考这篇博客
以下是代码实现:
#include <iostream> #include "opencv2/core.hpp" #include "opencv2/imgproc.hpp" #include "opencv2/highgui.hpp" using namespace std; using namespace cv; #define CLIP_RANGE(value, min, max) ( (value) > (max) ? (max) : (((value) < (min)) ? (min) : (value)) ) #define COLOR_RANGE(value) CLIP_RANGE(value, 0, 255) #define PI 3.1415926 /* * Adjust Brightness and Contrast * @param src [in] InputArray * @param dst [out] OutputArray * @param brightness [in] integer, value range [-255, 255] * @param contrast [in] integer, value range [-255, 255] * @return 0 if success, else return error code */ int adjustBrightnessContrast(Mat src, Mat& dst, int brightness, int contrast) { if (src.empty()) { return -1; } brightness = CLIP_RANGE(brightness, -255, 255); contrast = CLIP_RANGE(contrast, -255, 255); /* Algorithm of Brightness Contrast transformation The formula is: y = [x - 127.5 * (1 - B)] * k + 127.5 * (1 + B); x is the input pixel value; y is the output pixel value; B is brightness, value range is [-1,1]; k is used to adjust contrast; k = tan( (45 + 44 * c) / 180 * PI ); c is contrast, value range is [-1,1]; especially: when B = 0, y = (x-127.5)*k + 127.5, adjust Contrast only; when c = 0, k = 1, y = x + 255*B, adjust Brightness only; */ double B = brightness / 255.; double c = contrast / 255.; double k = tan((45 + 44 * c) / 180 * PI); Mat lookupTable(1, 256, CV_8U); uchar *p = lookupTable.data; for (int i = 0; i < 256; i++) p[i] = COLOR_RANGE((i - 127.5 * (1 - B)) * k + 127.5 * (1 + B)); LUT(src, lookupTable, dst); return 0; } //=====主程序开始==== static Mat src; static int brightness = 255; static int contrast = 255; static void callbackAdjust(int, void *) { Mat dst; adjustBrightnessContrast(src, dst, brightness - 255, contrast - 255); imshow("photo", dst); } int main() { src = imread("D:\\1.jpg"); if (!src.data) { cout << "error read image" << endl; return -1; } namedWindow("photo"); createTrackbar("brightness", "photo", &brightness, 2 * brightness, callbackAdjust); createTrackbar("contrast", "photo", &contrast, 2 * contrast, callbackAdjust); callbackAdjust(0, 0); waitKey(); destroyAllWindows(); return 0; }