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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 detect the angle between two lines in real time by tensorflow

Our graduation project is to track human motion at real time while doing an exercise and then give him feedback if that exercise is right or wrong and instructions to make it a perfect one, so we split the code into two parts. The first one is…
Aya N. Mohammed
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copy-move forgery detection using key-points in python

I'm trying to detect copy-move forgery through key points. I'm using this This above image has tampered ( the number 4 is copied and moved). I got the key points (number = 891) and descriptors for each keypoint. The shape of descriptors =…
roronoa
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ARKit keypoints in image coordinates (2D)

Description of the "issue": I want to use keypoints (a.k.a. tie points) between two successive images from an Apple smartphone using ARKit but I can't find these. I can find 3D values in world reference frame from the ARPointCloud or…
swiss_knight
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Keypoint Descriptor Matching: How to calculate a goodness-of-fit per template?

I am not sure whether this belongs on stackoverflow or another stackexchange site - input very welcome here. I have used python OpenCV to match a target image's BRISK keypoint descriptors to - in turn - three different templates. What is a…
jtlz2
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Can SIFT3D works on point cloud in both XYZ and XYZRGB format?

I am new to PCL and SIFT3D. When I use feature_demo.cpp to evaluate keypoints, I noticed that if the point cloud is XYZRGB, keypoints can be detected with certain parameters set properly. However, if the point cloud is XYZ without the RGB channels,…
Cloud Guy
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SimpleBlobDetection keypoints not visually centered (opencv C++)

I am trying to use opencv's simple blob detector to determine the colors on the face of a Rubik's cube. I have been using this fantastic resource so far and it has proved to be very helpful and descriptive. After a fair bit of tweaking, I have been…
CynicalPassion63
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Object of type 'KeyPoint' is not JSON serializable opencv

I am trying to send a server request with the image keypoints and descriptor as a json object... here is my code.. import cv2 import requests import json imgDetail = {'keypoints': '', 'descriptor': ''} sift = cv2.xfeatures2d.SIFT_create() img =…
Nibir Alam
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How to find the model files for facemark->load model of OpenCV_Contrib?

bool myDetector(cv::InputArray image, cv::OutputArray faces, cv::CascadeClassifier *face_cascade){ cv::Mat gray; if (image.channels() > 1) cvtColor(image, gray, CV_BGR2GRAY); else gray = image.getMat().clone(); equalizeHist(gray,…
Hsmlee
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Overfitting problems for key points model (detecting wrists, elbows, shoulders, etc.)

I'm building a model to detect keypoints of body parts. To do that I'm using the COCO dataset (http://cocodataset.org/#download). I'm trying to understand why I'm running into overfitting issues (training loss converges, but I reach a ceiling really…
megashigger
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Multi target regression when some targets have correct NA labels

I'm working on a Keras neural net that does key point prediction of body parts (left foot, left knee, left hip, etc.). For each image (X), the target (Y) is a list of coordinates for the keypoints (left_foot_x, left_foot_y, left_knee_x,…
megashigger
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Moments of many objects (Python OpenCV)

I have an image that contains ~400 dots. I've been using the Simpleblob detector to find the keypoints. I then for loop over all keypoints to find the center of each of the keypoints (code below). This works well, but I'm also interested in the…
D Palo
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PointCloud library: Compute sift keypoints - input cloud error

I am trying to compute the sift keypoints of an input cloud with this code: #include #include #include #include #include…
Adrián Arroyo Perez
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ucrtbase.dll: An invalid parameter was passed to a function that considers invalid parameters fatal

I'm currently working on a personal project with OpenCV and I have a few issues during the execution of the program. After implementing an AKAZE + BOW recognizer (which didn't seem to work well enough for my problem) I wanted to try out a SIFT (and…
Marchius
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How to overlay a numpy matrix of points onto an image in opencv?

I used dlib and numpy to extract the list of facial keypoints. Code: def get_landmarks(im): rects = detector(im, 1) if len(rects) > 1: raise TooManyFaces if len(rects) == 0: raise NoFaces return numpy.matrix([[p.x,…
Rich
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How to compute recall-precision of descriptors for RGB-D images

Recently, I have made research on descriptors for RGB-D images, but I'm facing problems on how to compute the recall-precision now. My direct thoughts are, first, after detecting and describing the keypoints, converting the two depth images into…
Xz.Xiao
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