Using FeatureDetector in OpenCV gives access violation

c++, feature-detection, opencv

Solution

for SIFT and SURF, you'll need the nonfree module, that is :

include "opencv2/nonfree/nonfree.hpp"

call cv::initModule_nonfree() at the beginning

link against opencv_nonfree2.4.x.lib

Problem

I need to find and match feature points in stereo images. Therefore I want to compare the different Feature Detection algorithms that are supported in OpenCV 2.4.5. by passing "SURF", "SIFT", etc. to the function. The code snippet: ``` #include "opencv2/opencv.hpp" #include <opencv/highgui.h> #include <opencv2/nonfree/features2d.hpp> using namespace cv; using namespace std; ... void DisparityAnalysis::detectKeyPoints(Mat1b leftImageGrey, Mat1b rightImageGrey, string algorithmName) { Ptr<FeatureDetector> detector = FeatureDetector::create(algorithmName); detector->detect(leftImageGrey, keypoints_1); detector->detect(rightImageGrey, keypoints_2); } ``` The error: ``` Unhandled exception at 0x770b15de in DisparityAnalysis.exe: 0xC0000005: Access violation reading location 0x00000000. ``` I've already searched for solutions and found this one: Access violation reading in FeatureDetector OpenCV 2.4.5 The difference I've recognized is, that they use cv::initModule_nonfree() at the beginning. But when copying it into my code it doesn't compile because the identifier isn't found. Any suggestions?

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