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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

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Python Bag of Words clustering

Edit: Here is the complete code for anyone having issues still github.com I'm trying to do an image recognition project using SIFT and BOW. So far, I'm trying to train and build my dictionary. I've read in images from 5 different classes, computed…
blurb
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Compute Dense SIFT features in OpenCV 3.0

Since version 3.0, DenseFeatureDetector is no longer available. Could anybody please show me how to compute Dense SIFT features in OpenCV 3.0? I couldn't find it in the documentation. Thank you very much in advance!
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OpenCV3.0 - module has no attribute SIFT

I am using Ubuntu 12.04. I recently installed OpenCV 3.0 from https://github.com/Itseez/opencv/archive/3.0.0-alpha.zip. I want to do feature matching for which I used the following code: import numpy as np import cv2 from matplotlib import pyplot as…
Clive
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How to remove false matches from FLANNBASED Matcher in OPENCV?

[Request you to read question details before marking it duplicate or down-voting it. I have searched thoroughly and couldn't find a solution and hence posting the question here.] I am trying to compare one image with multiple images and get a list…
milan m
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SIFT() in opencv is not working: 'module' object has no attribute 'SURF'

I am trying to run the simplest opencv SIFT code through the shell of Ubuntu, with no luck I get an error: AttributeError: 'module' object has no attribute 'SURF' The code: import cv2 cv2.SIFT() My configurations: Ubuntu version is 13.10…
Oz Radiano
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SIFT matches and recognition?

I am developing an application where I am using SIFT + RANSAC and Homography to find an object (OpenCV C++,Java). The problem I am facing is that where there are many outliers RANSAC performs poorly. For this reasons I would like to try what the…
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Sift Extraction - opencv

I'm trying to get started working with sift feature extraction using (C++) OpenCv. I need to extract features using SIFT, match them between the original image (e.g. a book) and a scene, and after that calculate the camera pose. So far I have found…
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Sift comparison, calculate similarity score, python

I need to get the similarity score of two images, I'm using the SIFT Comparison, I've followed the tutorial Feature Matching but It's missing the score calculation. You'll find below the code That I used for the sift comparison : import numpy as…
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Error with matches1to2 with Opencv SIFT

I am getting an error: line 33, in img3 = cv2.drawMatches(img1,kp1,img2,kp2,matches,None,flags=2) TypeError: Expected cv::DMatch for argument 'matches1to2' When I try to execute this code. It is supposed to be a simple image comparison in…
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How to use opencv feature matching for detecting copy-move forgery

In my opencv project, I want to detect copy-move forgery in an image. I know how to use the opencv FLANN for feature matching in 2 different image, but I am become so confused on how to use FLANN for detection copy-move forgery in an image. P.S1: I…
Mohamad MohamadPoor
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Recognizing an image from a list with OpenCV SIFT using the FLANN matching

The point of the application is to recognize an image from an already set list of images. The list of images have had their SIFT descriptors extracted and saved in files. Nothing interesting here: std::vector…
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How to get a fixed size SIFT feature vector?

I am trying to obtain feature vectors for N =~ 1300 images in my data set, one of the features I have to implement is shape. So I plan to use SIFT descriptors. However, each image returns different number of keypoints, so I run [F,D] =…
jeff
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Sift Implementation :: Keypoints from different octaves

I am trying to implement SIFT in MATLAB. I have obtained keypoints for (say) 4 different octaves by locating local maxima and minima in DOG (difference of gaussian) space. However I am at loss at what to do with the keypoints from the last 3…
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How to use SIFT/SURF as features for a machine learning algorithm?

Im working on an automatic image annotation problem in which im trying to associate tags with images. For that im trying for SIFT features for learning. But the problem is all the SIFT features are a set of keypoints, each of which have a 2-D array,…
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Phash vs. SIFT in identifying similar image

I have questions about both sift and phash First of all, I'm using SIFT to identify similar image in real-time service. Like pictures by phone-camera, small amount of rotation and blurred effect could be. And I found Phash. So, I test phash on its…
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