1、获取图像像素指针
1、CV_Assert(myImage.depth() == CV_8U);
2、Mat.ptr(int i=0) 获取像素矩阵的指针,索引i表示第几行,从0开始行数。
3、获得当前行指针const uchar* current= myImage.ptr(row );
4、获取当前像素点P(row, col)的像素值 p(row, col) =current[col]
像素范围处理saturate_cast
saturate_cast(-100),返回 0。
saturate_cast(288),返回255
saturate_cast(100),返回100
这个函数的功能是确保RGB值得范围在0~255之间
2、掩膜操作解释
3、filter2D函数
注:图片From 51CTO学院!!侵权删
#include<opencv2/opencv.hpp>
#include<iostream>
#include<math.h>
using namespace cv;
int main() {
Mat src,dst;
src = imread("F:\\opencv_work\\03矩阵的掩膜操作\\Project1\\27.jpg");
// if (src.empty())
//{
// cout << "can not find image" << endl;
// return -1;
//}
namedWindow("总舵主的自画像", WINDOW_AUTOSIZE);
imshow("总舵主的自画像",src);
//double t1 = getTickCount();
//int cols = (src.cols - 1) * src.channels(); //行
//int offsetx = src.channels(); //RGB三通道 计算col
//int rows = src.rows;
//dst = Mat::zeros(src.size(), src.type());
//for (int row = 1; row < (rows - 1); row++){
// const uchar* previous = src.ptr<uchar>(row - 1);
// const uchar* current = src.ptr<uchar>(row);
// const uchar* next = src.ptr<uchar>(row + 1);
// uchar* output = dst.ptr<uchar>(row);
// for (int col = offsetx; col < cols; col++){
// output[col] = saturate_cast<uchar>(5 * current[col] - (current[col - offsetx] + current[col + offsetx] + previous[col] + next[col]));
// }
//}
//double timeconsume1 = (getTickCount() - t1) / getTickFrequency();
//printf("timeconsume1 %.2f\n", timeconsume1);
double t2 = getTickCount();
Mat kernel = (Mat_<char>(3, 3) << 0, -1, 0, -1, 5, -1, 0, -1, 0);
filter2D(src, dst, src.depth(), kernel);
double timeconsume2 = (getTickCount() - t2) / getTickFrequency();
printf("timeconsume2 %.2f\n", timeconsume2);
namedWindow("舵主的对比度图像", WINDOW_AUTOSIZE);
imshow("舵主的对比度图像", dst);
waitKey(0);
return(0);
}
程序运行结果: