PROSAGA码农传奇-模式识别-<unknown>在detectAndCompute（）中发生错误

<div class =“post-text”itemprop =“text”>
  <P>
    要缩小范围，请尝试拆分
     <code>
      detectAndCompute()
    </code>
     成
     <code>
      detect()
    </code>
     和
     <code>
      compute()
    </code>
    ：
  </p>
   <pre>
    <code>
      #include <stdio.h>
#include <iostream>
#include "opencv2/core.hpp"
#include "opencv2/features2d.hpp"
#include "opencv2/xfeatures2d.hpp"
#include "opencv2/highgui.hpp"

using namespace cv;
using namespace cv::xfeatures2d;

std::vector<cv::KeyPoint> keypoints2;
cv::Mat descriptors2;

static void createKeypointsAndDescriptors(const cv::Mat& matInput) {
  //-- Step 1: Detect the keypoints using SURF Detector, compute the descriptors
    double minHessian = 400;
    Ptr<SURF> detector = SURF::create();
    detector->setHessianThreshold(minHessian);

detector->detect(matInput, keypoints2);
    detector->compute(matInput, keypoints2, descriptors2);
    // detector->detectAndCompute( matInput, noArray(), keypoints2, descriptors2 );        
...
}

</code>
  </pre>
  <H2>
    链接：
  </H2>
  <P>
    <a href="https://docs.opencv.org/3.4/d5/df7/classcv_1_1xfeatures2d_1_1SURF.html" rel="nofollow noreferrer">
       <code>
        cv::xfeatures2d::SURF Class Reference
      </code>
    </A>
    <BR/>
    <a href="https://docs.opencv.org/3.4/d0/d13/classcv_1_1Feature2D.html#a8be0d1c20b08eb867184b8d74c15a677" rel="nofollow noreferrer">
       <code>
        cv::Feature2D Class Reference
      </code>
    </A>
    <BR/>
    <a href="https://docs.opencv.org/3.4/d4/db2/classcv_1_1xfeatures2d_1_1AffineFeature2D.html#a96d437af348dc676a3860d755555a249" rel="nofollow noreferrer">
       <code>
        cv::xfeatures2d::AffineFeature2D Class Reference
      </code>
    </A>
  </p>
</DIV>