opencv::调整图像亮度与对比度

 

 

图像变换能够看做以下： - 像素变换 – 点操做 - 邻域操做 – 区域 调整图像亮度和对比度属于像素变换-点操做

 

//建立一张跟原图像大小和类型一致的空白图像、像素值初始化为0
Mat new_image = Mat::zeros( image.size(), image.type() ); //确保值大小范围为0~255之间
saturate_cast<uchar>(value) //给每一个像素点每一个通道赋值
Mat.at<Vec3b>(y,x)[index]=value

 

int main(int argc, char** argv) { Mat src, dst; src = imread(STRPAHT2); if (!src.data) { printf("could not load image...\n"); return -1; } char input_win[] = "input image"; cvtColor(src, src, CV_RGB2GRAY); namedWindow(input_win, CV_WINDOW_AUTOSIZE); imshow(input_win, src); int height = src.rows; int width = src.cols; //建立一张跟原图像大小和类型一致的空白图像、像素值初始化为0
    dst = Mat::zeros(src.size(), src.type()); float alpha = 1.2; float beta = 30; Mat m1; src.convertTo(m1, CV_32F); for (int row = 0; row < height; row++) { for (int col = 0; col < width; col++) { if (src.channels() == 3) { float b = m1.at<Vec3f>(row, col)[0];// blue
                float g = m1.at<Vec3f>(row, col)[1]; // green
                float r = m1.at<Vec3f>(row, col)[2]; // red // output
                dst.at<Vec3b>(row, col)[0] = saturate_cast<uchar>(b*alpha + beta); dst.at<Vec3b>(row, col)[1] = saturate_cast<uchar>(g*alpha + beta); dst.at<Vec3b>(row, col)[2] = saturate_cast<uchar>(r*alpha + beta); } else if (src.channels() == 1) { float v = src.at<uchar>(row, col); dst.at<uchar>(row, col) = saturate_cast<uchar>(v*alpha + beta); } } } char output_title[] = "contrast and brightness change demo"; namedWindow(output_title, CV_WINDOW_AUTOSIZE); imshow(output_title, dst); waitKey(0); return 0; }