OpenCV 如何创建 DescriptorExtractor 对象

OpenCV how to create a DescriptorExtractor object

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

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

但是我有以下错误信息:

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

DescriptorExtractor 是一个抽象 class,所以你不能实例化它。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);

注意也存在FeatureDetector,这是检测关键点的通用接口,所以你可以这样做:

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