calcOpticalFlowPyrLK.cpp

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#include "mexopencv.hpp"
#include "opencv2/video.hpp"
using namespace std;
using namespace cv;

void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
    // Check the number of arguments
    nargchk(nrhs>=3 && (nrhs%2)==1 && nlhs<=3);

    // Argument vector
    vector<MxArray> rhs(prhs, prhs+nrhs);

    // Option processing
    vector<Point2f> nextPts;
    Size winSize(21,21);
    int maxLevel = 3;
    TermCriteria criteria(TermCriteria::COUNT+TermCriteria::EPS, 30, 0.01);
    int flags = 0;
    double minEigThreshold = 1e-4;
    for (int i=3; i<nrhs; i+=2) {
        string key(rhs[i].toString());
        if (key == "InitialFlow") {
            nextPts = rhs[i+1].toVector<Point2f>();
            flags |= cv::OPTFLOW_USE_INITIAL_FLOW;
        }
        else if (key == "WinSize")
            winSize = rhs[i+1].toSize();
        else if (key == "MaxLevel")
            maxLevel = rhs[i+1].toInt();
        else if (key == "Criteria")
            criteria = rhs[i+1].toTermCriteria();
        else if (key == "GetMinEigenvals")
            UPDATE_FLAG(flags, rhs[i+1].toBool(), cv::OPTFLOW_LK_GET_MIN_EIGENVALS);
        else if (key == "MinEigThreshold")
            minEigThreshold = rhs[i+1].toDouble();
        else
            mexErrMsgIdAndTxt("mexopencv:error",
                "Unrecognized option %s", key.c_str());
    }

    // Process
    vector<Point2f> prevPts(rhs[2].toVector<Point2f>());
    Mat status, err;
    if (rhs[0].isNumeric() && rhs[1].isNumeric()) {
        // images
        Mat prevImg(rhs[0].toMat(CV_8U)),
            nextImg(rhs[1].toMat(CV_8U));
        calcOpticalFlowPyrLK(prevImg, nextImg, prevPts, nextPts, status,
            (nlhs>2 ? err : noArray()), winSize, maxLevel, criteria, flags,
            minEigThreshold);
    }
    else if (rhs[0].isCell() && rhs[1].isCell()) {
        // pyramids
        vector<Mat> prevImg(rhs[0].toVector<Mat>()),
                    nextImg(rhs[1].toVector<Mat>());
        calcOpticalFlowPyrLK(prevImg, nextImg, prevPts, nextPts, status,
            (nlhs>2 ? err : noArray()), winSize, maxLevel, criteria, flags,
            minEigThreshold);
    }
    else
        mexErrMsgIdAndTxt("mexopencv:error", "Invalid image argument");
    plhs[0] = MxArray(nextPts);
    if (nlhs>1)
        plhs[1] = MxArray(status);
    if (nlhs>2)
        plhs[2] = MxArray(err);
}