OpenCV的projectPoints函数

Question

我目前正在尝试实现OpenCV的projectPoints方法的示例。该方法的思想是将一组3D点、给定相机的平移/旋转向量及其畸变系数作为输入，输出对应的图像平面上的2D点。

代码源如下：

#include "opencv2/core/core.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/calib3d/calib3d.hpp"
#include "opencv2/highgui/highgui.hpp"

#include <iostream>
#include <string>

std::vector<cv::Point3d> Generate3DPoints();

int main(int argc, char* argv[])
{
    // Read 3D points
    std::vector<cv::Point3d> objectPoints = Generate3DPoints();
    std::vector<cv::Point2d> imagePoints;

    cv::Mat intrisicMat(3, 3, cv::DataType<double>::type); // Intrisic matrix
    intrisicMat.at<double>(0, 0) = 1.6415318549788924e+003;
    intrisicMat.at<double>(1, 0) = 0;
    intrisicMat.at<double>(2, 0) = 0;

    intrisicMat.at<double>(0, 1) = 0;
    intrisicMat.at<double>(1, 1) = 1.7067753507885654e+003;
    intrisicMat.at<double>(2, 1) = 0;

    intrisicMat.at<double>(0, 2) = 5.3262822453148601e+002;
    intrisicMat.at<double>(1, 2) = 3.8095355839052968e+002;
    intrisicMat.at<double>(2, 2) = 1;

    cv::Mat rVec(3, 1, cv::DataType<double>::type); // Rotation vector
    rVec.at<double>(0) = -3.9277902400761393e-002;
    rVec.at<double>(1) = 3.7803824407602084e-002;
    rVec.at<double>(2) = 2.6445674487856268e-002;

    cv::Mat tVec(3, 1, cv::DataType<double>::type); // Translation vector
    tVec.at<double>(0) = 2.1158489381208221e+000;
    tVec.at<double>(1) = -7.6847683212704716e+000;
    tVec.at<double>(2) = 2.6169795190294256e+001;

    cv::Mat distCoeffs(5, 1, cv::DataType<double>::type);   // Distortion vector
    distCoeffs.at<double>(0) = -7.9134632415085826e-001;
    distCoeffs.at<double>(1) = 1.5623584435644169e+000;
    distCoeffs.at<double>(2) = -3.3916502741726508e-002;
    distCoeffs.at<double>(3) = -1.3921577146136694e-002;
    distCoeffs.at<double>(4) = 1.1430734623697941e+002;

    std::cout << "Intrisic matrix: " << intrisicMat << std::endl << std::endl;
    std::cout << "Rotation vector: " << rVec << std::endl << std::endl;
    std::cout << "Translation vector: " << tVec << std::endl << std::endl;
    std::cout << "Distortion coef: " << distCoeffs << std::endl << std::endl;

    std::vector<cv::Point2f> projectedPoints;

    cv::projectPoints(objectPoints, rVec, tVec, intrisicMat, distCoeffs, projectedPoints);

    /*for (unsigned int i = 0; i < projectedPoints.size(); ++i)
    {
        std::cout << "Image point: " << imagePoints[i] << " Projected to " << projectedPoints[i] << std::endl;
    }*/

    std::cout << "Press any key to exit.";
    std::cin.ignore();
    std::cin.get();

    return 0;
}

std::vector<cv::Point3d> Generate3DPoints()
{
    std::vector<cv::Point3d> points;

    double x, y, z;

    x = .5; y = .5; z = -.5;
    points.push_back(cv::Point3d(x, y, z));

    x = .5; y = .5; z = .5;
    points.push_back(cv::Point3d(x, y, z));

    x = -.5; y = .5; z = .5;
    points.push_back(cv::Point3d(x, y, z));

    x = -.5; y = .5; z = -.5;
    points.push_back(cv::Point3d(x, y, z));

    x = .5; y = -.5; z = -.5;
    points.push_back(cv::Point3d(x, y, z));

    x = -.5; y = -.5; z = -.5;
    points.push_back(cv::Point3d(x, y, z));

    x = -.5; y = -.5; z = .5;
    points.push_back(cv::Point3d(x, y, z));

    for(unsigned int i = 0; i < points.size(); ++i)
    { 
        std::cout << points[i] << std::endl << std::endl;
    }

    return points;
}

当我尝试运行projectPoints方法时，应用程序崩溃了，我不知道为什么。任何帮助将不胜感激。

- user3019217

---

错误具体在哪里？ - Drew McGowen

应用程序在以下位置崩溃：cv::projectPoints(objectPoints, rVec, tVec, intrisicMat, distCoeffs, projectedPoints)。错误信息为：“在OpenCVTest.exe的0x000007FEFCC3940D处发生了一次首要异常：Microsoft C++异常：cv::Exception，内存位置为0x00000000002BB840。” - user3019217

我遇到了一个断言失败的错误：OpenCV Error: Assertion failed (mtype == type0 || (CV_MAT_CN(mtype) == CV_MAT_CN(type0) && ((1 << type0) & fixedDepthMask) != 0)) in create, file /home/me/opencv/modules/core/src/matrix.cpp, line 1486 terminate called after throwing an instance of 'cv::Exception' what(): /home/me/opencv/modules/core/src/matrix.cpp:1486: error: (-215) mtype == type0 || (CV_MAT_CN(mtype) == CV_MAT_CN(type0) && ((1 << type0) & fixedDepthMask) != 0) in function create。 - sop

抱歉，我贴错了输出。错误是：OpenCV 错误：在 cv::_OutputArray::create 中发生断言失败（mtype == type0 || (CV_MAT_CN(mtype) == CV_MAT_CN(type0) && ((1 << type0) & fixedDepthMask) != 0)），文件 C:\builds\2_4_PackSlave-win64-vc12-shared\opencv\modules\core\src\matrix.cpp，行 1486。 - user3019217

Answer 1

看起来这里在抱怨输出点向量的类型。尝试替换你对projectPoints的调用：

cv::projectPoints(objectPoints, rVec, tVec, intrisicMat, distCoeffs, projectedPoints);

通过此调用：

cv::projectPoints(objectPoints, rVec, tVec, intrisicMat, distCoeffs, imagePoints);

使用变量类型为std::vector<cv::Point2d>而不是std::vector<cv::Point2f>。

- BConic