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Questions tagged [vlfeat]

VLFeat is an open source library that implements popular computer vision algorithms

VLFeat includes implementations of HOG, SIFT, MSER, k-means, hierarchical k-means, agglomerative information bottleneck, SLIC superpixels, and quick shift. It is written in C for efficiency and compatibility, with interfaces in MATLAB for ease of use, and detailed documentation throughout.

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runtime error of vlsift: input image contains a malformed PGM header

I am trying to test sift detector of vlfeat computer vision library by running sift.c file in src folder. I have successfully compiled and run the program. However, I got the error: the input image contains a malformed PGM header. I am sure it is…
neouyghur
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VLFeat: computation of number of octaves for SIFT

I am trying to go through and understand some of VLFeat code to see how they generate the SIFT feature points. One thing that has me baffled early on is how they compute the number of octaves in their SIFT computation. So according to the…
Luca
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Compiling a Matlab code with a VLfeat library in java

I'm having trouble compiling my Matlab code in java (with the matlab compiler tool) because I use VLfeat inside my code. This is the error it generates: Error using loadlibrary (line 447) There was an error loading the library…
Cloé Dana
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vl_sift() not working in Octave?

I installed the vlfeat library using apt-get install octave-vlfeat. For some reason, the SIFT function does not work, and says "vl_sift() undefined". This is at the same time when functions like vl_hog() and vl_kmeans() do work perfectly fine. No…
a-Jays
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How do I binarize Fisher Vectors?

I'm working on a school project and, between many tasks, I need to binarize Fisher Vectors following what is written in this paper. I was given the vl_feat library to use with Matlab and I implementd this simple tutorial to return fisher vectors…
G4bri3l
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Can not find -lvl when using compile vlfeat library

I try to use VLFEAT in my own project. Follow the instructions provided in its main page, I still have a question. First, I compile the library using g++ 'make ARCH=glnx86'.It seems OK.And then I use a small program to check whether it is compiled…
Donghui Sun
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VLFeat kmeans C API explanation

I'm trying to use VLFeat's kmeans implementation in C but I'm having a really hard time understanding how it works. Note: I am using the C API in a C++ program, so any code posted by me here is C++. Additionally, I am using the Eigean header…
marcman
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Null/No SIFT descriptor and keypoints generated in python

I am trying to create a codebook from a set of image patches. I have divided the images (Caltech 101) into 20 X 20 image patches. I want to create a SIFT descriptor for each patch. But for some of the image patches, it does not return any…
cosmorise
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How to use vlfeat sift matching function in C code?

I just found one similar question here. But I just want to do a matching based on the description result from vlfeat. The goal to detect if an image contains the object in another image, based on sift feature description extracting and matching. And…
mrmoment
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VLFeat compile for Octave: broken makefile

I'm attempting to complie VLFeat for use with Octave but the *.d files all end up in the VLFeat root directory. Which then causes the following error to appear for most of the files. mv: cannot stat ‘./toolbox/geometry/vl_irodr.d’: No such file or…
chibi03
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Vlfeat installation for Octave in Ubuntu14.04

I am trying to install Vlfeat support for octave in Ubuntu 14.04. I am following the instructions at the following link: http://www.vlfeat.org/install-octave.html . However when I run the command MKOCTFILE=mkoctfile make I get the following…
Anurag Saran
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Libsvm finds vlfeat

For my Computer Vision course I use vlfeat to perform SIFT and dense SIFT over an image. I perform some data manipulation and then I wish to use libsvm to train an SVM, using the function svmtrain. My problem is that I get an error which states that…
Cassie
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Dense SIFT Keypoints & Descriptor Extraction using vlfeat

I'm currently using Dense SIFT from vlfeat. But I got only a single keypoint & descriptor out from the code. But the number of keypoints returned was more. How to extract all the keypoints & descriptors. Also Descriptor was a single value and it…
Sabarinathan Vadivelu
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Vlfeat in Octave- 'invalid use of script in index expression'

I am having trouble getting the Vlfeat computer vision library in Octave to work. I compiled it following the instructions on the vlfeat website http://www.vlfeat.org/install-octave.html But when i try to run vl_version, octave gives me this…
user3922963
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K-means Clustering, major understanding issue

Suppose that we have a 64dim matrix to cluster, let's say that the matrix dataset is dt=64x150. Using from vl_feat's library its kmeans function, I will cluster my dataset to 20 centrers: [centers, assignments] = vl_kmeans(dt, 20); centers is a…
Thms
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