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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.

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How to visualize descriptors and keypoints from raw pointcloud?

I am trying to extract NARF keypoints and descriptors for raw pointcloud data using pcl::NarfKeypoint , pcl::NarfDescriptor. In visualization process, I can simply plot my keypoints along with the range image generated from the original…
Farid Alijani
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matchShapes() opencv giving false positives

I am trying to find an object image into a scene image. I am using opencv to detect the keypoints using SURF. I am using matchDescriptors to match the object descriptors with the scene descriptors, however this is resulting always in object found.…
estiv
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What are the main rates and values we should figure to evaluate both feature detection, description and matching?

I work on palmprint recognition using feature2D with Open_CV library, and I use algorithms such as SIFT, SURF, ORB... to detect features and extract/match descriptors. My test include (1 vs 1) palmprint and also (1 vs Data Base) of palmprint. Ones…
BrainabilGH
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How to detect landmark positions from caricature faces?

I have been working on the problem of recognizing faces from given caricatures using the IIIT-CFW dataset So far, I have tried using Python's dlib library for detecting landmark points from the cartoon faces. However, it doesn't seem to work well on…
Saurav--
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Key-point Detection and Image Stitching

]2 So as shown in the image below, i have key points detected on the image but the output image after wrap perspective neglects the first image on the left side, cannot figure out why ! import numpy as np import imutils import cv2 class…
Anand Sonawane
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Simple pygame user interface

I'm trying to create a script that allows a user to cycle through a directory of images, and for each one mark key points (left click marks the green circle, and right click marks the red one). FYI the script is to be used to create a labeled…
Omeed
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OpenCV C++ create reusable set of keypoints and descriptors for stitching multiple images

I have created a program that can stitch multiple images together and am now looking to improve the efficiency of it. Depending on the size of the stitched image, eventually it is to large and contains too many keypoints that the machine runs out of…
C.Radford
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Find pixel coordinates in an input image in keypoint matching algorithm using opencv?

I want to find out a given image in an input image......first I used template matching using opencv but its not giving proper result. So I switched to keypoint matching using SIFT with opencv. But I am not able to find pixel location in a input…
himanshu sangal
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why is homography needed in object recognition problems?

I have been asked to do sift key-point matching and then homography matrix estimation. Why do i need the homography matrix in object recognition problems? This is the kind of images I am trying to recognise1
wannabegeek
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OpenCV transformation from two images

Theres is a MATLAB example that matches two images and outputs the rotation and scale: https://de.mathworks.com/help/vision/examples/find-image-rotation-and-scale-using-automated-feature-matching.html?requestedDomain=www.mathworks.com My goal is to…
MaxMKA
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SIFT keypoints in sift.detect

How are keypoints stored using the sift.detect method in opencv ? Are they in the form of an array ? How to extract the (x,y) coordinates of each keypoint? ( I am using opencv 2.4.11)
Sammyak Sangai
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Which keypoint detector is used by ARToolkit(version 5)?

In their blog post , they have mentioned that they use FREAK descriptor but they haven't mentioned which detector are they using to identify the keypoints . Does anybody know anything about it???
kartik
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How to detect key-points that lies on the ground plane?

I have two images from the same video sequence. I find correspondent key-points on them as follows My goal is to detect the homography that relates both ground planes in image 1 and image 2 (without calibrating the camera). So my current problem…
Ricardo
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Python, cv2, provide your own Keypoints

I have two images that I want to compare. I am using orb.detect and orb.compute for this purpose. My problem is that I want to feed certain key points and I am not able to find a way to do that. I have tried things like: originalx =…
Sergio gdlhr
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reconstruct the keypoints from consecutive images

I have some consecutive images,and had extract the keypoints of every image. If these images all has 8 same keypoints,is there any algorithm to build the 8 keypoints' world coordinate? I had googled that euclidean reconstruction may could done…
zdczdcc
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