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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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Bag-of-Words (BOW) in VLFeat

I'm building a project Images Classification with Bag-of-Visual-Words (BoVW) using VLFeat library. The BoVW pipeline includes: SIFT k-means Building histogram SVM classification I can use vl_sift and vl_kmeans for (1) and (2), but I don't know how…
Huy Phan
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I have some issue during adding VLFEAT to MATLAB 7.10.0 (R2010a)

My malab installation folder is C:\Program Files\MATLAB\R2010a\bin\matlab.exe and I have added vlfeat to my current user folder: C:\Users\Patrick\Documents\MATLAB\vlfeat-0.9.18\toolbox\vl_setup I have created a startup file startup.m in…
Patrick
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MATLAB image() is rotated after hold on

I'm printing an image like this : img = imread('path/to/image.jpg'); image(img); this is fine, but when I do img = imread('path/to/image.jpg'); hold on; image(img); image is rotated 180 degrees. Any ideas why, and how to fix this ? Why am I doing…
jeff
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How to use vl_covdet in Python

Can anybody tell me how i can use vl_covdet in python? Currently I am only using the sift provided by vlfeat but i am not getting the desired features through this method. cmmd = str("/home/hassan/vlfeat/bin/glnxa64/sift "+imagename+"…
user3450399
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Why Vlfeat generates same number of descriptors for different images?

I notice that Vlfeat/Sift generates same number of descriptors for different images, why? And what is the aim of orientation assignment? It seems there is a similar process in the descriptor formation process. I am quite new to the SIFT and…
Shan Luo
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VLFeat error in MATLAB R2010a - hists{ii} = getImageDescriptor(model, im);

I am using the vl_sift tool of to extract features from a set of images for classification. On running phow_caltech101(), the command prompt throws me an error as follows, hists{ii} = getImageDescriptor(model, im); ??? Undefined function or method…
user236956
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Histogram of Oriented Gradients as feature vectors with vlfeat/libsvm

I am quite newbie on vlfeat library for computer vision and I have problems dealing with it. What i am trying to do is using the Histograms of Oriented Gradients (HOG) as feature vectors to classify in LIBSVM images with different dimensions. The…
mad
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Using Vlfeat's C API for quickshift

I have installed vlfeat on my pc and seem to have got it working on netbeans. I am currently trying to use vlfeat's quickshift function but I am unable to find any references on how to do the following: Import input images in vlfeat's C/C++ code…
mystique
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Weird phenomenon with SVM: negative examples score higher

I use the VL-Feat and LIBLINEAR to handle the 2-category classification. The #(-)/#(+) for the training set is 35.01 and the dimension of each feature vector is 3.6e5. I have around 15000 examples. I have set the weight of positive example to be…
Peiyun
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Dense sift using VLFeat

I am having trouble understanding the dense sift documentation in vlfeat shown at http://www.vlfeat.org/matlab/vl_dsift.html. They have mentioned a bin size parameter for the width of the grid at a pixel and have mentioned a step parameter for…
anon
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I want to use vlfeat for recognizing one class

I'm trying to use the vlfeat (matlab) example caltech101 for just one class but it doesn't seem to work. If I only feed one class to the svm trainer the results are 50/50. Should I take something else into account or is it that the one class svm…
paghdv
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phow_caltech101 to change categories in matlab (vlfeat)

I'm studying the Caltech101 computer vision dataset using Matlab.. I wanted to classify and train the images of caltech-101 using phow_caltech.m file but there was a problem, I don't know how to change the categories... these are what I did. setup…
Jang_Hyunwoong
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Installing pyvlfeat on Windows: cannot find -lboost_python-mt-py26

I'm trying to install pyvlfeat on python in Windows. For installing this module, I had to install boost.python. I installed and compiled the boost with bjam --with-python toolset=gcc --layout=tagged After this I tried to install pyvlfeat by python…
Aress
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calculate number of matches between two images using MATLAB vl_sift

I’m new to MATLAB. I’m using VL_Feat library. I’m trying to construct a code that can calculate number of matching points between two images. Up to now I know how to match two images. What I want to get is number of matching points. As an example…
Chathuranga Bandara
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How to Compile vlfeat library on Octave

I want to use vlfeat library on Octave but the vlfeat.org does not have instructions for installing it on Octave. Any help/pointers would be appreciated.
user1403483
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