Common interface of 2D image Descriptor Extractors

Class for computing descriptors for image keypoints.

Extractors of keypoint descriptors in OpenCV have wrappers with a common interface that enables you to easily switch between different algorithms solving the same problem. This section is devoted to computing descriptors represented as vectors in a multidimensional space. All objects that implement the vector descriptor extractors inherit the DescriptorExtractor interface.

In this interface, a keypoint descriptor can be represented as a dense, fixed-dimension vector of a basic type. Most descriptors follow this pattern as it simplifies computing distances between descriptors. Therefore, a collection of descriptors is represented as a matrix, where each row is a keypoint descriptor.

Example

detector = cv.FeatureDetector('ORB');
keypoints = detector.detect(img);
extractor = cv.DescriptorExtractor('ORB');
descriptors = extractor.compute(img, keypoints);