OpenCV的 - 使用FLANN與ORB描述我使用的OpenCV 3.2</p> <p>我試圖使用FLANN在比蠻力更快地匹配功能描述匹配功能

Question

。

// Ratio to the second neighbor to consider a good match. 
#define RATIO 0.75 

void matchFeatures(const cv::Mat &query, const cv::Mat &target, 
        std::vector<cv::DMatch> &goodMatches) { 
    std::vector<std::vector<cv::DMatch>> matches; 
    cv::Ptr<cv::FlannBasedMatcher> matcher = cv::FlannBasedMatcher::create(); 
    // Find 2 best matches for each descriptor to make later the second neighbor test. 
    matcher->knnMatch(query, target, matches, 2); 
    // Second neighbor ratio test. 
    for (unsigned int i = 0; i < matches.size(); ++i) { 
     if (matches[i][0].distance < matches[i][1].distance * RATIO) 
      goodMatches.push_back(matches[i][0]); 
    } 
} 

此代碼正在使用SURF和SIFT描述符，但與ORB無關。

OpenCV Error: Unsupported format or combination of formats (type=0) in buildIndex 

，因爲它是說here，FLANN需要描述爲類型CV_32F的，所以我們需要將它們轉換。

if (query.type() != CV_32F) query.convertTo(query, CV_32F); 
if (target.type() != CV_32F) target.convertTo(target, CV_32F); 

然而，這個所謂的修復程序返回我一個錯誤convertTo功能。

OpenCV Error: Assertion failed (!fixedType() || ((Mat*)obj)->type() == mtype) in create 

這種說法在opencv/modules/core/src/matrix.cpp文件，行2277

發生了什麼事？

---

代碼複製問題。

#include <opencv2/opencv.hpp> 

int main(int argc, char **argv) { 
    // Read both images. 
    cv::Mat image1 = cv::imread(argv[1], cv::IMREAD_GRAYSCALE); 
    if (image1.empty()) { 
     std::cerr << "Couldn't read image in " << argv[1] << std::endl; 
     return 1; 
    } 
    cv::Mat image2 = cv::imread(argv[2], cv::IMREAD_GRAYSCALE); 
    if (image2.empty()) { 
     std::cerr << "Couldn't read image in " << argv[2] << std::endl; 
     return 1; 
    } 
    // Detect the keyPoints and compute its descriptors using ORB Detector. 
    std::vector<cv::KeyPoint> keyPoints1, keyPoints2; 
    cv::Mat descriptors1, descriptors2; 
    cv::Ptr<cv::ORB> detector = cv::ORB::create(); 
    detector->detectAndCompute(image1, cv::Mat(), keyPoints1, descriptors1); 
    detector->detectAndCompute(image2, cv::Mat(), keyPoints2, descriptors2); 
    // Match features. 
    std::vector<cv::DMatch> matches; 
    matchFeatures(descriptors1, descriptors2, matches); 
    // Draw matches. 
    cv::Mat image_matches; 
    cv::drawMatches(image1, keyPoints1, image2, keyPoints2, matches, image_matches); 
    cv::imshow("Matches", image_matches); 
} 

Answer 1

您是否調整過FLANN參數？

從http://docs.opencv.org/3.0-beta/doc/py_tutorials/py_feature2d/py_matcher/py_matcher.html

兩者在使用ORB，您可以通過以下。評論值是根據文檔推薦的，但在某些情況下它沒有提供所需的結果。其他值工作得很好：

index_params =字典（算法= FLANN_INDEX_LSH， table_number = 6，＃12 key_size = 12，＃20 multi_probe_level = 1）＃2

也許你可以轉換到C++ API？