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Questions tagged [keypoint]

In computer vision field a keypoint is an interest point detected by the SIFT algorithm. Use this tag for programming issues related to the use of keypoints in the field of computer vision.

is an algorithm that finds "keypoints" in images that are robust to scale variations, perspective and lighting. In order to identify those keypoints, descriptors are generated basing on the surrounding pixels of the keypoint. This way, the same keypoints can be located in different images, which is called matching.

Programing questions related to keypoints in computer vision applications are an appropriate field for this tag.

187 questions
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Finding hamming distance between ORB feature descriptors

I am trying to write a function to match ORB features. I am not using default matchers (bfmatcher, flann matcher) because i just want match speific features in image with features in other image. I saw ORS descriptor its a binary array. My query is…
nayab
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How to draw detected keypoints on an image in java/javacv?

Can anyone tell me that how can i detect keypoints of an image and draw that keypoints on that image in java? I tried smt but i couldn't figure out how to draw them? Any ideas for how should i proceed or any ideas for drawing for my code? final…
cgbs
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KeyPoint descriptor OpenCV

I am trying to understand how to get the descriptor for a given KeyPoint in OpenCV. So far my code looks like follows: #include #include "opencv2/opencv.hpp" typedef cv::Mat Image; int main(int argc, const char * argv[]) { Image…
BRabbit27
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OpenCV 2.4.6 SIFT KeyPoints Detection using a lot of memory

We were using SIFT in openCV 2.4.3 and we decided to upgrade to openCV 2.4.6. After the upgrade, the memory usage jumped from about (150MB) to 1.2GB in openCV 2.4.6. Does someone knows if is this a bug or something that we need to configure now? Our…
Oberdan Nunes
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3D to 2D matching

I have point clouds (each point has a colour) of objects and images that show these objects. I want to find interest points in 2D/3D and match those so I know which parts of my image (at least those that had interest points) are found in the point…
Chad Moklav
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What is .distance after doing a knnMatch?

Basically I have: BruteForceMatcher>().knnMatch(descriptor1,descriptor2,matches,2); To get only good matches I parse all the "matches" vectors and check the distance like this: if( (matches[i][0].distance / matches[i][1].distance) < ratio…
anon
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finding bounding box of centroid with limited information

I have detected blob keypoints in opencv c++. The centroid displays fine. How do I then draw a bounding box around the detected blob if I only have the blob center coordinates? I can't work backwards from center because of too many unknowns(or so I…
user121903
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How to train a custom keypoint detector for drone pose estimation. Detectron2

Because I couldn't find the answer elsewhere I decided to describe my issue here. I'm trying to create keypoints detector of the Eachine TrashCan Drone for estimating its pose. I followed some tutorials. The first one was with the TensorFlow…
BrunoK
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In Colab doing image data augmentation with "imgaug" is not working as intended

I am augmenting my image data-set which also contains key-points. For this reason I am using imgaug library. Following is the augmentation code: kps = KeypointsOnImage(__keypoints, shape=_image.shape) seq = iaa.Sequential([ iaa.Affine( …
hafiz031
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TensorFlow - keypoint detection yields a heatmap of zeros

I'm using a detection-based CNN for hand pose estimation(finding hand joints in a depth image of a single hand). My plan was to first use an FCN to find the 2D coordinates of all the 16 key points. The backbone is ResNet-50-FPN and the computation…
Harper Long
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Structuring keypoints as an input for a neural network

Background I have a neural network that outputs key points for pose (feet, ankles, knees, arms, head, etc.) and the connections - basically I've got a skeleton. I'd like to use these key points /skeleton as an input to another neural network - a…
megashigger
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PCL: PFH with ISS keypoints

Currently I try to compute PFH descriptors for ISS keypoints. I perform the following steps: (1) Detect keypoints with pcl::ISSKeypoint3D (2) Estimate normals of the new keypoint cloud from (1) with pcl::NormalEstimation (3) Estimate PFH for the…
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training data augmentation in caffe along with its multilabel

How to randomly crop training images along with its position label. I'm preprocessing images data and its labels for caffe input. I want to crop my training images randomly online (when caffe running) and I know caffe provide a random crop param in…
farever
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GridAdaptedFeatureDetector disappeared from OpenCV 3.1?

I'm working on an algorithm that should recognize an object from an image in a video file. For now, I want to use ORB(I know that SURF and SIFT are better at this kind of job, but I want to make this affirmation based on my results). Now I have one…
patri
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what is equivalent of scale in opencv sift keypoint

In my opencv project I try to compute sift features, I detect keypoints and compute descriptors. What I know it should contains 4 parameter: X, Y, Scale and Orientation. The opencv keypoint structure has pt (X, Y coordination) and angle…
Mohamad MohamadPoor
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