Opencv3——遍历Mat像素值

#include <opencv2/opencv.hpp>

#include <iostream>

using namespace cv;

using namespace std;

int main(int artc, char** argv) {

         Mat src = imread("D:/test.png");

         if (src.empty()) {

                  printf("could not load image... ");

                  return -1;

         }

         namedWindow("input", CV_WINDOW_AUTOSIZE);

         imshow("input", src);

         // 直接读取图像像素

         int height = src.rows;

         int width = src.cols;

         int ch = src.channels();

         for (int c = 0; c < ch; c++) {

                  for (int row = 0; row < height; row++) {

                          for (int col = 0; col < width; col++) {

                                   if (ch == 3) {

                                            Vec3b bgr = src.at<Vec3b>(row, col);

                                            bgr[0] = 255 - bgr[0];

                                            bgr[1] = 255 - bgr[1];

                                            bgr[2] = 255 - bgr[2];

                                            src.at<Vec3b>(row, col) = bgr;

                                   } else if(ch == 1) {

                                            int gray = src.at<uchar>(row, col);

                                            src.at<uchar>(row, col) = 255 - gray;

                                   }

                          }

                  }

         }

         imshow("output", src);

         waitKey(0);

         return 0;

}