OpenCV

Question

我有一个程序可以将模板图像中找到的特征点与视频源中显示的特征点相匹配。当我运行程序时出现以下错误：

OpenCV Error: Assertion failed (i1 >= 0 && i1 < static_cast<int>(keypoints1.size())) in drawMatches, file bin/opencv-2.4.7/modules/features2d/src/draw.cpp, line 207
terminate called after throwing an instance of 'cv::Exception'
  what():  bin/opencv-2.4.7/modules/features2d/src/draw.cpp:207: error: (-215) i1 >= 0 && i1 < static_cast<int>(keypoints1.size()) in function drawMatches

Aborted

这就是上面提到的函数drawMatches：

drawMatches(img_1, templateKeypoints, frames, keypoints_1, good_matches, img_matches, cv::Scalar::all(-1), cv::Scalar::all(-1), std::vector<char>(), cv::DrawMatchesFlags::NOT_DRAW_SINGLE_POINTS);

根据我的阅读，我认为问题在于如果视频中找到的特征点与模板图像中的特征点不匹配，那么程序就会中止。

min_dist = 100;      
for(int i = 0; i < img_descriptors_1.rows; i++) {
        if(matches[i].distance <= 3 * min_dist) {
          good_matches.push_back(matches[i]);
        }
      }

我一直在寻找运行的视频源，即使没有匹配项。

编辑：

我注意到，如果我反复尝试运行该程序，我有时会收到另一条错误消息：

OpenCV Error: Assertion failed (npoints >= 0 && points2.checkVector(2) == npoints && points1.type() == points2.type()) in findHomography, file /home/colin/bin/opencv-2.4.7/modules/calib3d/src/fundam.cpp, line 1074
terminate called after throwing an instance of 'cv::Exception'
  what():  /home/colin/bin/opencv-2.4.7/modules/calib3d/src/fundam.cpp:1074: error: (-215) npoints >= 0 && points2.checkVector(2) == npoints && points1.type() == points2.type() in function findHomography

Aborted

Answer 1

紧接以下：

extractor.compute(img_1, keypoints_1, descriptors_1);
extractor.compute(frame, keypoints_2, descriptors_2);

请添加：

if ((descriptors_1.empty()) || (descriptors_2.empty()))
continue;

由于在特定帧中没有找到关键点，因此应该进行下一次迭代并检查新帧。这解决了我的问题。

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