OpenCV如何创建DescriptorExtractor对象

Question

我正在使用OpenCV C ++库，但我无法创建DescriptorExtractor对象。 这是我做的：

Mat img = imread("testOrb.jpg",CV_LOAD_IMAGE_UNCHANGED);
std::vector<KeyPoint> kp;
cv::Ptr<cv::ORB> detector = cv::ORB::create();
detector->detect( img, kp )
//this part works    

DescriptorExtractor descriptorExtractor;    
Mat descriptors;
descriptorExtractor.compute(img, kp, descriptors);
//when these 3 lines are added, an error is thrown

但是我有以下错误消息：

OpenCV Error: The function/feature is not implemented () in detectAndCompute, file ...

Answer 1

DescriptorExtractor是抽象类，因此您无法实例化它。它只是描述符提取器的通用接口。你可以这样做：

Ptr<DescriptorExtractor> descriptorExtractor = ORB::create();
Mat descriptors;
descriptorExtractor->compute(img, kp, descriptors);

请注意，还存在FeatureDetector，这是检测关键点的通用界面，因此您可以这样做：

std::vector<KeyPoint> kp;
Ptr<FeatureDetector> detector = ORB::create();
detector->detect(img, kp);