Mat image;
image = imread("E:\\Penguins.jpg");
namedWindow("My Test");
imshow("My Test", image);Mat m1;
bitwise_not(image, m1);//像素反转
namedWindow("反转", CV_WINDOW_NORMAL);
imshow("反转", m1);

Mat image;
image = imread("E:\\Penguins.jpg");
namedWindow("My Test");
imshow("My Test", image);
//更改三通道image的像素值	
int heights = image.rows;int widths = image.cols;int nc = image.channels();for (int row = 0; row < heights; row++){for (int col = 0; col< widths; col++){if (nc==1){float gray = image.at<uchar>(row, col);image.at<uchar>(row, col) = 0;}else if (nc==3){int b = image.at<Vec3b>(row, col)[0];int g = image.at<Vec3b>(row, col)[1];int r = image.at<Vec3b>(row, col)[2];image.at<Vec3b>(row, col)[0] = 255-b;image.at<Vec3b>(row, col)[1] = g;image.at<Vec3b>(row, col)[2] = r;}}}

Mat image;
image = imread("E:\\Penguins.jpg");
namedWindow("My Test");
imshow("My Test", image);Mat image_gray;int heights = image.rows;int widths = image.cols;int nc = image.channels();for (int row = 0; row < heights; row++){for (int col = 0; col< widths; col++){if (nc==1){float gray = image.at<uchar>(row, col);image.at<uchar>(row, col) = 0;}else if (nc==3){int b = image.at<Vec3b>(row, col)[0];int g = image.at<Vec3b>(row, col)[1];int r = image.at<Vec3b>(row, col)[2];image_gray.at<uchar>(row, col) = min(r, min(b, g));//取三个通道的最小值}}}namedWindow("取三个通道的最小值", CV_WINDOW_NORMAL);imshow("取三个通道的最小值", image_gray);

Mat image;
image = imread("E:\\Penguins.jpg");
namedWindow("My Test");
imshow("My Test", image);Mat image_gray;cvtColor(image, image_gray, CV_BGR2GRAY);int heights = image.rows;int widths = image.cols;int nc = image_gray.channels();for (int row = 0; row < heights; row++){for (int col = 0; col< widths; col++){if (nc==1){float gray = image_gray.at<uchar>(row, col);image_gray.at<uchar>(row, col) = 255-gray;}else if (nc==3){int b = image_gray.at<Vec3b>(row, col)[0];int g = image_gray.at<Vec3b>(row, col)[1];int r = image_gray.at<Vec3b>(row, col)[2];}}}namedWindow("反转单通道值", CV_WINDOW_NORMAL);imshow("反转单通道值", image_gray);