opencv学习笔记（02）——遍历图像（指针法）

#include <opencv2\core\core.hpp>

#include <opencv2\highgui\highgui.hpp>

#include <opencv2\imgproc\imgproc.hpp>

#include <iostream>



void colorReduce(cv::Mat& image, int div=64)

{

    int nr = image.rows;    

    int nc = image.cols * image.channels();



    int n = static_cast<int>( cv::log(static_cast<double>(div)) / cv::log(2.0) );

    uchar mask = 0xFF << n;



    for(int i=0; i<nr; i++)

    {

        uchar* data = image.ptr<uchar>(i);

        for(int j=0; j<nc; j++)

        {

            //*data++ = *data - *data % div + div / 2;

            *data++ = (*data & mask) + div / 2;

        }

    }



}





int main(int argc, char** argv)

{



    cv::Mat img = cv::imread("F:\\images\\boldt.jpg");    

    cv::Mat img2 = img.clone();    



    double duration;

    duration = static_cast<double>(cv::getTickCount());



    colorReduce(img2);

    duration = static_cast<double>(cv::getTickCount()) - duration;

    duration /= cv::getTickFrequency();



    cv::namedWindow("original");    

    cv::imshow("original", img);

    cv::namedWindow("altered");    

    cv::imshow("altered", img2);



    std::cout << duration << std::endl;



    cv::waitKey(0);

    return 0;



}