C++在成員函數中創建thread多線程, 以成員函數作爲回調函數時的範例

以下代碼來自VSLAM開源算法ORB_SLAM2中的部分代碼，其開源網址爲https://github.com/raulmur/ORB_SLAM2

回調函數&成員函數：

void Initializer::FindHomography(vector<bool> &vbMatchesInliers, float &score, cv::Mat &H21)
{
    // Number of putative matches
    const int N = mvMatches12.size();

    // Normalize coordinates
    vector<cv::Point2f> vPn1, vPn2;
    cv::Mat T1, T2;
    Normalize(mvKeys1,vPn1, T1);
    Normalize(mvKeys2,vPn2, T2);
    cv::Mat T2inv = T2.inv();

    // Best Results variables
    score = 0.0;
    vbMatchesInliers = vector<bool>(N,false);

    // Iteration variables
    vector<cv::Point2f> vPn1i(8);
    vector<cv::Point2f> vPn2i(8);
    cv::Mat H21i, H12i;
    vector<bool> vbCurrentInliers(N,false);
    float currentScore;

    // Perform all RANSAC iterations and save the solution with highest score
    for(int it=0; it<mMaxIterations; it++)
    {
        // Select a minimum set
        for(size_t j=0; j<8; j++)
        {
            int idx = mvSets[it][j];

            vPn1i[j] = vPn1[mvMatches12[idx].first];
            vPn2i[j] = vPn2[mvMatches12[idx].second];
        }

        cv::Mat Hn = ComputeH21(vPn1i,vPn2i);
        H21i = T2inv*Hn*T1;
        H12i = H21i.inv();

        currentScore = CheckHomography(H21i, H12i, vbCurrentInliers, mSigma);

        if(currentScore>score)
        {
            H21 = H21i.clone();
            vbMatchesInliers = vbCurrentInliers;
            score = currentScore;
        }
    }
}

在成員函數：

Initializer::Initializer(const Frame &ReferenceFrame, float sigma, int iterations)

中創建thread線程：

    // Launch threads to compute in parallel a fundamental matrix and a homography
    vector<bool> vbMatchesInliersH, vbMatchesInliersF;
    float SH, SF;
    cv::Mat H, F;

    thread threadH(&Initializer::FindHomography,this,ref(vbMatchesInliersH), ref(SH), ref(H));

Tips：

1. 傳遞了“this”指針
2. 傳遞引用參數要用到“std::ref”來Constructs an object of the appropriate reference_wrapper type to hold a reference to elem