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Questions tagged [sift]

Scale-invariant feature transform (SIFT) is an algorithm in computer vision to detect and describe local features in images. This tag is for programming questions related to SIFT implementation or programs that use SIFT algorithm for computer vision applications.

Scale-invariant feature transform (SIFT) is an algorithm in computer vision to detect and describe local features in images, introduced by prof. David Lowe in 2004.

The local features extracted from an image with SIFT can then be used to identify an object from that image. This visualization illustrates homologous SIFT keypoints in two separate pictures of the same magazine cover:

enter image description here

Applications of SIFT include object recognition, robotic mapping and navigation, image stitching, 3D modeling, gesture recognition, video tracking, and match moving.

Algorithm Steps

  • Scale-space extrema detection

  • Keypoint localization

  • Interpolation of nearby data for accurate position

  • Discarding low-contrast keypoints

  • Eliminating edge responses

  • Orientation assignment

  • Keypoint descriptor

More information can be obtained here

837 questions
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Keypoints detection in OpenCV with SIFT

i have a problem with Keypoints detection of an image in OpenCV. If i have for example a SIFT detector, when it detects an image it retrives 1000 keypoints but if i split the image in two "sub-image", and foreach SIFT detects keypoints, the sum is…
Vertex
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How can I use SIFT in opencv 2.4

I want to use SIFT. I've already tried this code: import cv2 import numpy as np img = cv2.imread('1.jpg') gray= cv2.cvtColor(img,cv2.COLOR_BGR2GRAY) sift = cv2.xfeatures2d.SIFT_create() kp = sift.detect(gray,None) …
Dev
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C++ - SiftFeatureDetector is not loading

I am currently trying to use OpenCV's SiftFeatureDetector. However, this happens: Click This Link For Image I saw that I needed the nonfree files. This is where i got my files…
ianc1339
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Can be__shfl_xor replaced in order to run on sm_21?

Trying to run this: https://github.com/Celebrandil/CudaSift on a NVS4200M, which is sm_21, not sm_35 as required. The only problem in running the mentioned project is this code (cudaSiftD.cu:205): for (int i=1;i<=16;i*=2) sum +=…
Alex Fliker
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Image Analysis: sift / harris / affine / RANSAC

I am not sure if this falls under the criteria of a proper question, but still, I would like to give it a shot. I am looking for a library or function that takes two SIFT descriptors in a form of a file (or a matrix) of…
Plump Worm
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Sift Lowe, VLFeat Sift, Python Photogrammetry Toolbox

I do not have much programming experience, and I am currently working on a project with photogrammetry. I'm testing out the Python Photogrammetry Toolbox, which allows the user to select Sift Lowe or VLFeat Sift for the feature detection process.…
Jimmy
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SIFT and HOG features descriptors

Heyyy,,, Im going to do classification. And for the descriptor I planning to use the HOG and SIFT descriptors from LOWE.. 1. For HOG, is that true that we need to compute the gradient of all image's pixels?? For example we have image with size…
user3378327
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SIFT feature extractor

Which one is the feature in SIFT .Is key Point or descriptor .I am trying to cluster .which one should I consider for clustering and why?. This cluster data is used for classification.
madan ram
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How do I use SIFT in OpenCV 4.2.0 with C++?

I am using visual studio 2017. Opencv and opencv verison of 4.2.0 is installed and files are generated using cmake. xfeatured2d420.lib is linked with compiler. And also #include "opencv2/xfeatures2d.hpp" #include "opencv2/xfeatures2d/nonfree.hpp"…
alexander
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SIFT and Keypoint

I would like to ask how is SIFT algorithm done in C++. I understand that SIFT extracts keypoints. In that case, what will be the value represented by the keypoints extracted by SIFT algorithm? And how can I compare and detect similar keypoints? I…
dennis anacan
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Import wikipedia from sift.corpora

I'm new to spark and cannot import wikipedia package from sift.corpora. I'm getting this error. " ImportError: No module named 'sift.corpora ". Here is the notebook I'm working on. Thank you for your…
A. A
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Which feature descriptors to use and why?

I do like to do compute the position and orientation of a camera in a civil aircraft cockpit. I do use LEDs as fixed points. My plan is to save their X,Y,Z Position associated with the LED. How can I detect and identify my LEDs on my images? Which…
Jakob Alexander Eichler
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