OpenCV 2.4.12例外

Question

我使用OrbFeatureDetector和Flann处理来自PC摄像头的视频。当我调用 knnSearch 时，无论是发布还是调试，我都会遇到以下异常：

  

OpenCV错误：断言失败（query.isContinuous（）＆amp;＆amp;   indices.isContinuous（）＆amp;＆amp; dists.isContinuous（））in   cv :: flann :: runKnnSearch_，file   E：\ Library \ opencv2.4.12 \ sources \ modules \ flann \ src \ miniflann.cpp，第487行

通常这不会出现。通常在相机被遮盖时发生。

这是正常的吗？如何避免？

我的代码：

#include <opencv2\opencv.hpp>
#include <iostream>
using namespace cv;

int main()
{
    // LoadImage
    Mat srcImage = imread("1.jpg");
    imshow("Image to Find", srcImage);
    Mat srcImage_gray;
    cvtColor(srcImage, srcImage_gray, CV_BGR2GRAY);

    // Detect key points from source image 
    OrbFeatureDetector featureDetector;
    vector<KeyPoint> srcKeyPoints;
    featureDetector.detect(srcImage_gray, srcKeyPoints);

    // Compute description from source image
    OrbDescriptorExtractor featureExtractor;
    Mat description;
    featureExtractor.compute(srcImage_gray, srcKeyPoints, description);

    // FLANN
    flann::Index flannIndex(description, flann::LshIndexParams(12, 20, 2), cvflann::FLANN_DIST_HAMMING);

    // Initialize camera
    VideoCapture cap(0);
    cap.set(CV_CAP_PROP_FRAME_WIDTH, 640);
    cap.set(CV_CAP_PROP_FRAME_HEIGHT, 480);
    uint32_t frameCount = 0;    

    // Start
    while (true) {
        Mat captureImage, captureImage_gray;
        cap >> captureImage;
        if (captureImage.empty())
            continue;

        cvtColor(captureImage, captureImage_gray, CV_BGR2GRAY);

        // Detect key points from camera
        vector<KeyPoint> captureKeyPoints;
        Mat captureDescription;
        featureDetector.detect(captureImage_gray, captureKeyPoints);

        // Compute description from camera
        featureExtractor.compute(captureImage_gray, captureKeyPoints, captureDescription);

        // knnSearch
        Mat matchIndex(captureDescription.rows, 2, CV_32SC1);
        Mat matchDistance(captureDescription.rows, 2, CV_32FC1);
        try {
            // !!!! Here comes exceptions !!!!
            flannIndex.knnSearch(captureDescription, matchIndex, matchDistance, 2, flann::SearchParams());
        }
        catch (Exception e) {
        }

        // Good matches
        vector<DMatch> good;
        for (int i = 0; i < matchDistance.rows; i++) {
            if (matchDistance.at<float>(i, 0) < 0.6 * matchDistance.at<float>(i, 1)) {
                DMatch dmatches(i, matchIndex.at<int>(i, 0), matchDistance.at<float>(i, 0));
                good.push_back(dmatches);
            }
        }

        // Show Image
        Mat resultImage;
        drawMatches(captureImage, captureKeyPoints, srcImage, srcKeyPoints, good, resultImage);
        imshow("Matches", resultImage);

        if (char(waitKey(1)) == 27)
            break;
    }

    return 0;
}