How to calculate SURF points for ALL the points in an image using OpenCV?

Question

I need to calculate SURF features of a single specific point in the image using OpenCV. I am using SurfDescriptorExtractor to extract surf features, but it takes an array of keypoint as the arguemenet, which in turn was calculated by SurfFeatureDetector . Is there any way to use SurfDescriptorExtractor to calculate SURF feature of a single point?

Answer 1

Use push_back() function to fill the std::vector of cv::Keypoint . In your case, this array contains only one element. You can run compute function from class SurfDescriptorExtractor on this array with :

void compute( const cv::Mat& image, std::vector<cv::KeyPoint>& keypoints, cv::Mat& descriptors ) const;

Note that: Row i is the descriptor for keypoint i.