学习OpenCV（二）

来源：互联网发布：ppt mac破解版下载编辑：程序博客网时间：2024/06/05 00:36
/**本程序是学会使用：1、用下标访问像素，2、使用迭代器访问像素 ， 3、使用指针访问像素*4、把图像写入磁盘***/#include "highgui.h"//访问元素用下标void salt(cv::Mat &img , int n){for(int k = 0 ; k < n ; ++ k){int i = rand() % img.cols ;int j = rand() % img.rows ;if(1 == img.channels()){img.at<uchar>(j , i) = 255 ;}else if(3 == img.channels()){img.at<cv::Vec3b>(j , i)[0] = 255 ;img.at<cv::Vec3b>(j , i)[1] = 255 ;img.at<cv::Vec3b>(j , i)[2] = 255 ;}}//扩展：//cv::Mat_<uchar> im1 = img ;//im1(50 , 100) = 0 ;//对于已经知道返回类型时 可以这样访问元素}//减少图像颜色数void colorReduce(cv::Mat &img , int div = 64){int rowsNum = img.rows ;int closPiexlNum = img.cols * img.channels() ;for(int i = 0 ; i < rowsNum ; ++ i){uchar *data = img.ptr<uchar>(i) ;for(int j = 0 ; j < closPiexlNum ; ++ j){data[j] = data[j] / div * div + div / 2 ;}}}void colorReduce3(cv::Mat img , cv::Mat &result , int div = 64){result.create(img.rows , img.cols , img.type()) ;int rowsNum = img.rows ;int closPiexlNum = img.cols * img.channels() ;for(int i = 0 ; i < rowsNum ; ++ i){uchar *data_in = img.ptr<uchar>(i) ;uchar *data_out = result.ptr<uchar>(i) ;for(int j = 0 ; j < closPiexlNum ; ++ j){data_out[j] = data_in[j] / div * div + div / 2 ;}}}void colorReduce4(cv::Mat img , cv::Mat &result , int div = 64){//result.create(img.rows , img.cols , img.type()) ;result = img.clone() ;//注意两种迭代器的定义方法cv::MatIterator_<cv::Vec3b>   itStart = result.begin<cv::Vec3b>() ;cv::Mat_<cv::Vec3b>::iterator itEnd = result.end<cv::Vec3b>() ;while(itStart != itEnd){(*itStart)[0] = (*itStart)[0] / div * div + div / 2 ;(*itStart)[1] = (*itStart)[1] / div * div + div / 2 ;(*itStart)[2] = (*itStart)[2] / div * div + div / 2 ;itStart ++ ;}//Const迭代器两种定义方法//cv::MatConstIterator_<cv::Vec3b> it ;//cv::Mat_<cv::Vec3b>::const_iterator it ;}void colorReduce5(cv::Mat img , cv::Mat &result , int div = 64){result = img.clone() ;int rNum = result.rows ;int cNum = result.cols ;if(result.isContinuous()){cNum *= rNum ;rNum = 1 ;}int n = static_cast<int>(log(static_cast<double>(div)) / log(2.0)) ;uchar mask = 0xFF << n ;for(int i = 0 ; i < rNum ; ++ i){uchar *data = result.ptr<uchar>(i) ;for(int j = 0 ; j < cNum ; ++ j){*data++ = *data & mask + div / 2 ;*data++ = *data & mask + div / 2 ;*data++ = *data & mask + div / 2 ;}}}void colorReduce6(cv::Mat img , cv::Mat &result , int div = 64){int n = static_cast<int>(log(static_cast<double>(div)) / log(2.0)) ;uchar mask = 0xFF << n ;result = (img & cv::Scalar(mask , mask , mask)       + cv::Scalar(div / 2 , div / 2 , div / 2)) ;}int main(){cv::Mat img ;img = cv::imread("D:/Development/OpenCV/images/boldt.jpg") ; cv::namedWindow("Original") ;cv::imshow("Original" , img) ;//salt(img , 3000) ;//colorReduce(img , 64) ;//cv::Mat imgClone = img.clone() ;cv::Mat result ;//colorReduce3(img , result) ;//使用指针//colorReduce4(img , result) ;//使用迭代器//colorReduce5(img , result) ;//使用位运算colorReduce6(img , result) ;//简洁的写法cv::namedWindow("Result") ;cv::imshow("Result" , result) ;//cv::imwrite("result.jpg" , img) ;//把图像写在磁盘上cv::waitKey() ;return 0 ;}
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