c++ - calcopticalflowpyrlk 断言失败

Question

我正在尝试在 Ubuntu 上的 opencv 2.4.12 中使用以下代码进行视频稳定，我使用 calcopticalflowpyrlk，它会引发断言失败错误:错误如下:

OpenCV 错误:断言失败 ((npoints = prevPtsMat.checkVector(2, CV_32F, true)) >= 0) in cv::calcOpticalFlowPyrLK，文件主页...\opencv\modules\video\src\lkpyramid.cpp，第 845 行

代码如下:

#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <iostream>
#include <stdlib.h>

#include <opencv2/opencv.hpp>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>


using namespace cv;
using namespace std;




int main()
{

int rows = 240;
int cols = 240;
int i = 1;

VideoCapture cap(0);

Mat Canvass;
Canvass.create(rows, cols * 2, CV_8UC3);




for(;;)
{Mat prev,cur;

    Mat prev_gray,cur_gray, aligned;
    Mat TT(2, 3, CV_64F);

    vector <Point2f> cur_corner, cur_corner2, prev_corner2;
    vector <Point2f> prev_corner;
    Mat prev_grey;
    vector <uchar> status;
    vector <float> err;
    double dx, dy, da;

    const int max_no_of_corners = 20000;
    const double quality_of_corners = 0.00001;
    const double min_dist_bw_corners = 5;
    const int search_window_size = 80;
    const int pyramid_level = 5;

Mat cur_warped;
int rows = 240;
int cols = 240;


    if(i == 1)
    {   //capture the prev frame,resize,grayscale and display it
            for (int x = 0; x < 10;x++)
            {   cap >> prev; }

        resize(prev, prev,Size(240,240));
        cvtColor(prev,prev_gray,CV_BGR2GRAY);
        prev.copyTo(Canvass(Range::all(), Range(0,cols)));
                //capture the current frame,resize and grayscale it
        cap>>cur;
        resize(cur,cur,Size(240,240));
        cvtColor(cur,cur_gray,CV_BGR2GRAY);
        i++;
    }
    else{
           cap>>cur;
           resize(cur,cur,Size(240,240));
           cvtColor(cur,cur_gray,CV_BGR2GRAY);
           cvtColor(prev,prev_gray,CV_BGR2GRAY);
           //display the previous image in canvass
           cur.copyTo(Canvass(Range::all(), Range(0,cols)));

    }

            ///find corner points here

goodFeaturesToTrack(prev_grey, prev_corner, max_no_of_corners, quality_of_corners, min_dist_bw_corners);

    //usecalcopticalflowpyrlk
calcOpticalFlowPyrLK(prev_gray, cur_gray, prev_corner, cur_corner, status, err, Size(10,10),2);

//weed out bad matches
for (int t = 0; t < status.size(); t++) {
        if (int(status[t])) {

            cur_corner2.push_back(cur_corner[t]);
            prev_corner2.push_back(prev_corner[t]);
        }
    }



     //estimate transform
Mat T;
T = estimateRigidTransform(prev_corner2, cur_corner2,false);

if (T.data == NULL)
{cout<<"No transform found"<<endl;
      cur.copyTo(Canvass(Range::all(), Range(cols,cols * 2)));
      cur.copyTo(prev);
      }
    else{
                   cout<<"transform found "<<endl;
        // decompose T
        dx = T.at<double>(0, 2);
        dy = T.at<double>(1, 2);
        da = atan2(T.at<double>(1, 0), T.at<double>(0, 0));
        da = -da;
        //da = 0;
        TT.at<double>(0, 0) = cos(da);;
        TT.at<double>(0, 1) = -sin(da);
        TT.at<double>(1, 0) = sin(da);
        TT.at<double>(1, 1) = cos(da);
        TT.at<double>(0, 2) = -dx;// / scale;
        TT.at<double>(1, 2) = -dy;// / scale;
        //TT.copyTo(Transform);

//warp
warpAffine(cur, cur_warped, TT, cur.size(),INTER_NEAREST|WARP_INVERSE_MAP);
cur.copyTo(prev);
cur_warped.copyTo(Canvass(Range::all(), Range(cols,(cols * 2))));
}

imshow( "Output",Canvass);
 waitKey(1);
}

}

我认为 calcopticalflowpyrlk 中的 vector 数据类型可能存在一些问题，但我已经通过文档对其进行了验证，但我仍然遇到此错误。我该如何摆脱它？

Answer 1

你能显示和检查prev_corner.size()和cur_corner.size()吗？根据断言，这些 vector 似乎是空的。如果是这种情况 - 只需检查您是否有足够的特征点来寻找对应关系。

顺便说一句，您还应该在调用 estimateRigidTransform() 之前检查匹配项的数量；如果我没记错的话 - 它至少需要 3 个对应关系(估计 6 个自由度)。