javacv跟opencv有啥区别
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JavaCV是7个图形库的封装,可以调用OpenCV。OpenCV是1个独立的图形库,从第3版开始,底层是C++写的,以面向对象的方式封装。提供Java、Python的接口。OpenCV有Java接口,不需要另外下载JavaCV。但JavaCV是7个库的接口,功能更多。 参考技术A 前者 是后者的JAVA接口
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~ 参考技术B 平台不一样吧,opencv用于windows系统,是c++语言的,javacv没见过。本回答被提问者采纳
以下 3 个 opencv Mat 实例有啥区别?
【中文标题】以下 3 个 opencv Mat 实例有啥区别?【英文标题】:What is the difference between the following 3 opencv Mat instances?以下 3 个 opencv Mat 实例有什么区别? 【发布时间】:2016-07-04 09:31:12 【问题描述】:在我的程序中,我需要一个 3*3 矩阵 K(相机校准矩阵)和一个 3*3 矩阵 F(基本矩阵)来计算 E(基本矩阵):E = K.t()FK,但是当我使用
cv::Matx33d K (518.0, 0,325.5, 0,519.0,253.5, 0 , 0, 1);
它会产生错误:行中的“operator*”不匹配:
E = K.t() * F * K;
但是当我使用
cv::Mat K(3,3,CV_64FC1); //cannot be 32 (float)
K.at<double>(0,0) = 518.0;
K.at<double>(1,1) = 519.0;
K.at<double>(0,2) = 325.5;
K.at<double>(1,2) = 253.5;
K.at<double>(2,2) = 1;
它有效,但是当我使用时
cv::Mat_<double> K = ( cv::Mat_<double>(3, 3) <<
518.0, 0,325.5,
0 ,519.0,253.5,
0 , 0, 1);
它也可以,但与上面的结果完全不同
谁能告诉我这 3 个 opencv Mat 实例之间有什么区别?谢谢。
这是所有代码
#include <iostream>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/features2d/features2d.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/calib3d/calib3d.hpp>
using namespace std;
using namespace cv;
int main()
cout<<"Hello SLAM!"<<endl;
cv::Mat img1,img2,img;
// first method :can run ,but yeild fault result
cv::Mat K(3,3,CV_64FC1); //cannot be 32 (float)
K.at<double>(0,0) = 518.0;
K.at<double>(1,1) = 519.0;
K.at<double>(0,2) = 325.5;
K.at<double>(1,2) = 253.5;
K.at<double>(2,2) = 1;
// second method :cannont build
// cv::Matx33d K (518.0, 0,325.5,
// 0 ,519.0,253.5,
// 0 , 0, 1);//calibration matrix
// cv::Matx33d K=cv::Matx33d(518.0, 0,325.5,
// 0 ,519.0,253.5,
// 0 , 0, 1);//calibration matrix
// third method :can run ,yeild correcy result
cv::Mat_<double> K = ( cv::Mat_<double>(3, 3) <<
518.0, 0,325.5,
0 ,519.0,253.5,
0 , 0, 1);
img1= cv::imread("/home/kylefan/program/cmake_demo/image/rgb1.png",IMREAD_COLOR);
img2= cv::imread("/home/kylefan/program/cmake_demo/image/rgb2.png",IMREAD_COLOR);
vector<cv::Point2f> point1;
vector<cv::Point2f> point2;
cv::ORB orb;
vector<cv::KeyPoint>kp1,kp2;
cv::Mat desp1,desp2;
orb(img1,cv::Mat(),kp1,desp1,false);
orb(img2,cv::Mat(),kp2,desp2,false);
cv::Ptr<cv::DescriptorMatcher> matcher = cv::DescriptorMatcher::create("BruteForce-Hamming");
double knn_match_ratio = 0.3;
vector< vector<cv::DMatch>> matches_knn;
matcher->knnMatch(desp1,desp2,matches_knn,2);
vector<cv::DMatch> goodmatches;
for(int i=0;i<matches_knn.size();i++)
if(matches_knn[i][0].distance < knn_match_ratio * matches_knn[i][1].distance)goodmatches.push_back(matches_knn[i][0]);
if(goodmatches.size()<20)
cout<<"too less goodmatches "<<endl;
for(auto m:goodmatches)
point1.push_back(kp1[m.queryIdx].pt);
point2.push_back(kp2[m.queryIdx].pt);
// for(int j=0;j<goodmatches.size();j++)
//
// //cout<<j<<":"<<point1[j].x<<","<<point1[j].y<<","<<point2[j].x<<","<<point2[j].y<<","<<endl;
//
cv::Mat F = cv::findFundamentalMat(point1,point2,FM_RANSAC,3,0.99);//in calib3d
cv::Mat_<double> E = K.t() *F* K;
SVD svd(E);
cv::Matx33d W(0,-1,0,
1,0,0,
0,0,1);
cv::Mat_<double> R = svd.u * Mat(W) * svd.vt;
cv::Mat_<double> t = svd.u.col(2);
cv::Matx34d P1(R(0,0),R(0,1),R(0,2),t(0),
R(1,0),R(1,1),R(1,2),t(1),
R(2,0),R(2,1),R(2,2),t(2));
cout<<goodmatches.size()<<" goodmatches "<<endl;
cout<<"F="<<F<<endl;
cout<<"K="<<K<<endl;
cout<<"E="<<E<<endl;
cout<<"R="<<R<<endl;
cout<<"t="<<t<<endl;
cout<<"P1="<<P1<<endl;
if(fabsf(determinant(R))-1.0 > 1e-07)
cerr << "det(R) != +-1.0, this is not a rotation matrix" << endl;
else
cout<<"rotation matrix is right"<<endl;
return 0;
【问题讨论】:
【参考方案1】:在您的第二个版本中,您没有初始化矩阵元素,也没有设置它们。
cv::Mat K(3,3,CV_64FC1); //cannot be 32 (float)
K.at<double>(0,0) = 518.0;
K.at<double>(1,1) = 519.0;
K.at<double>(0,2) = 325.5;
K.at<double>(1,2) = 253.5;
K.at<double>(2,2) = 1;
这意味着索引 (0,1) 中可以有任何值; (1,0); (2,0) 和 (2,1)。
在创建时使用 0 进行初始化尝试:cv::Mat::zeros()
cv::Mat K = cv::Mat::zeros(3,3,CV_64FC1); //cannot be 32 (float)
K.at<double>(0,0) = 518.0;
K.at<double>(1,1) = 519.0;
K.at<double>(0,2) = 325.5;
K.at<double>(1,2) = 253.5;
K.at<double>(2,2) = 1;
【讨论】:
非常感谢,确实是这个原因,但是我的第一个版本有什么问题? cv::Matx33d K (518.0, 0,325.5, 0 ,519.0,253.5, 0 , 0, 1);谢谢! 是F
还是Matx33d
?
哦,我明白了,虽然 F 是 Mat ,K 而 K.t() 是 Matx33d,所以我写成 cv::Mat_以上是关于javacv跟opencv有啥区别的主要内容,如果未能解决你的问题,请参考以下文章