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List KeyPoint missing queryIdx

I am doing some feature matching and I am seeing that some KeyPoints in the list don't have the queryIdx listed, only the trainIdx. Is there an explanation for that?

Also, I'm not sure if they are related but I noticed that I have more matches than detected Keypoints.

List KeyPoint missing queryIdx

I am doing some feature matching and I am seeing that some KeyPoints in the list don't have the queryIdx listed, only the trainIdx. Is there an explanation for that?

Also, I'm not sure if they are related but I noticed that I have more matches than detected Keypoints.

Here is a snippet of my code:

    private MSER mFeatureDetector = MSER.create();
    mFeatureDetector.detect(ReferenceImage, ReferenceKeypoints);
    mDescriptorExtractor.compute(ReferenceImage, ReferenceKeypoints, ReferenceDescriptors);

    private final DescriptorExtractor mDescriptorExtractor = DescriptorExtractor.create(DescriptorExtractor.ORB);
    mFeatureDetector.detect(TestImage, TestKeypoints);
    mDescriptorExtractor.compute(TestImage, TestKeypoints, TestDescriptors);

    private final DescriptorMatcher DescriptorMatcher = DescriptorMatcher.create(DescriptorMatcher.BRUTEFORCE_HAMMINGLUT);
    DescriptorMatcher.match(ReferenceDescriptors,TestDescriptors, Matches);

    final List<DMatch> matchesList = Matches.toList();
    final List<KeyPoint> referenceKeypointsList = ReferenceKeypoints.toList();
    final List<KeyPoint> sceneKeypointsList = TestKeypoints.toList();
    final ArrayList<Point> goodReferencePointsList = new ArrayList<Point>();
    final ArrayList<Point> goodScenePointsList = new ArrayList<Point>();

    for (final DMatch match : matchesList) {
    goodReferencePointsList.add(referenceKeypointsList.get(match.trainIdx).pt);
    goodScenePointsList.add(sceneKeypointsList.get(match.queryIdx).pt);
    }

In the for-loop, I see there are often sceneKeypointsList.get(match.trainIdx).pt) but the sceneKeypointsList.get(match.queryIdx).pt) is blank.

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updated 2018-09-26 05:34:28 -0500

berak gravatar image

List KeyPoint missing queryIdx

I am doing some feature matching and I am seeing that some KeyPoints in the list don't have the queryIdx listed, only the trainIdx. Is there an explanation for that?

Also, I'm not sure if they are related but I noticed that I have more matches than detected Keypoints.

Here is a snippet of my code:

    private MSER mFeatureDetector = MSER.create();
    mFeatureDetector.detect(ReferenceImage, ReferenceKeypoints);
    mDescriptorExtractor.compute(ReferenceImage, ReferenceKeypoints, ReferenceDescriptors);

    private final DescriptorExtractor mDescriptorExtractor = DescriptorExtractor.create(DescriptorExtractor.ORB);
    mFeatureDetector.detect(TestImage, TestKeypoints);
    mDescriptorExtractor.compute(TestImage, TestKeypoints, TestDescriptors);

    private final DescriptorMatcher DescriptorMatcher = DescriptorMatcher.create(DescriptorMatcher.BRUTEFORCE_HAMMINGLUT);
    DescriptorMatcher.match(ReferenceDescriptors,TestDescriptors, Matches);

    final List<DMatch> matchesList = Matches.toList();
    final List<KeyPoint> referenceKeypointsList = ReferenceKeypoints.toList();
    final List<KeyPoint> sceneKeypointsList = TestKeypoints.toList();
    final ArrayList<Point> goodReferencePointsList = new ArrayList<Point>();
    final ArrayList<Point> goodScenePointsList = new ArrayList<Point>();

    for (final DMatch match : matchesList) {
    goodReferencePointsList.add(referenceKeypointsList.get(match.trainIdx).pt);
    goodScenePointsList.add(sceneKeypointsList.get(match.queryIdx).pt);
    }

In the for-loop, I see there are often sceneKeypointsList.get(match.trainIdx).pt) but the sceneKeypointsList.get(match.queryIdx).pt) is blank.

List KeyPoint missing queryIdx

I am doing some feature matching and I am seeing that some KeyPoints in the list don't have the queryIdx listed, only the trainIdx. Is there an explanation for that?

Also, I'm not sure if they are related but I noticed that I have more matches than the number of keypoints for my reference image does not match the number of keypoints detected Keypoints. from my test image.

Here is a snippet of my code:

    private MSER mFeatureDetector = MSER.create();
    mFeatureDetector.detect(ReferenceImage, ReferenceKeypoints);
    mDescriptorExtractor.compute(ReferenceImage, ReferenceKeypoints, ReferenceDescriptors);

    private final DescriptorExtractor mDescriptorExtractor = DescriptorExtractor.create(DescriptorExtractor.ORB);
    mFeatureDetector.detect(TestImage, TestKeypoints);
    mDescriptorExtractor.compute(TestImage, TestKeypoints, TestDescriptors);

    private final DescriptorMatcher DescriptorMatcher = DescriptorMatcher.create(DescriptorMatcher.BRUTEFORCE_HAMMINGLUT);
    DescriptorMatcher.match(ReferenceDescriptors,TestDescriptors, Matches);

    final List<DMatch> matchesList = Matches.toList();
    final List<KeyPoint> referenceKeypointsList = ReferenceKeypoints.toList();
    final List<KeyPoint> sceneKeypointsList = TestKeypoints.toList();
    final ArrayList<Point> goodReferencePointsList = new ArrayList<Point>();
    final ArrayList<Point> goodScenePointsList = new ArrayList<Point>();

    for (final DMatch match : matchesList) {
    goodReferencePointsList.add(referenceKeypointsList.get(match.trainIdx).pt);
    goodScenePointsList.add(sceneKeypointsList.get(match.queryIdx).pt);
    }

In the for-loop, I see there are often sceneKeypointsList.get(match.trainIdx).pt) but the sceneKeypointsList.get(match.queryIdx).pt) is blank.