Urgent: using the ORB to extract features of OPENCV descriptor descriptors and the size of Keypoints-CodePudding

I use the ORB of OPENCV to extract a series of image feature descriptor points descriptors and Keypoints, but after the extraction found Keypoints. The size ()=0, descriptors. The size ()=(0 x0) , please ask this is what reason, how should solve?

 Ptr The orb=orb: : create (); 
Vector Keypoints. 
Mat descriptors. 
Mat SRC=https://bbs.csdn.net/topics/imread (files1, 0); 
The resize (SRC, SRC, Size (48), 13); 
The orb - & gt; Detect (SRC, Keypoints); 
The orb - & gt; Compute (SRC, the Keypoints and descriptors); 
cout <"Key_size=" & lt; cout <"Orb_size=" & lt;  

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