OpenCV drawMatches - queryIdx和trainIdx [英] OpenCV drawMatches -- queryIdx and trainIdx

问题描述

这是OpenCV的 drawMatches（） function：

This is OpenCV's drawMatches() function:

void drawMatches(Mat img1, vector<KeyPoint> keypoints1,
                 Mat img2, vector<KeyPoint> keypoints2,
                 vector<DMatch> matches, 
                 Mat outImg) //want keypoints1[i] = keypoints2[matches[i]]

注意匹配是类型向量< DMatch> 。以下是 DMatch 构造函数： / p>

Notice that matches is of type vector<DMatch>. Here is the DMatch constructor:

DMatch(int queryIdx, int trainIdx, float distance)

假设 queryIdx 是一组关键点的索引， trainIdx 是另一组关键点的索引。

Presumably, queryIdx is an index into one set of keypoints, and trainIdx is an index into the other set of keypoints.

问题： queryIdx 索引到 keypoints2 和 trainIdx ？

The question: Is it true that queryIdx indexes into keypoints1, and trainIdx indexes into keypoints2? Or, is it the other way around?

推荐答案

这取决于你如何获得匹配。

That depends on how you get matches.

如果您按顺序调用match函数：

If you call match function in the order :

match(descriptor_for_keypoints1, descriptor_for_keypoints2, matches)

then queryIdx 指 keypoints1 和 trainIdx 指 keypoints2

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