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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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Vlfeat Matlab SVM

I'm trying to build an application for image processing, the purpose is to get thermal image and to decide if the image contains a human object or no. My thoughts were to try Matlab (actually Octave), for that mission i'm trying to use Vlfeat…
Yogevnn
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dense sift and vlfeat

I want to ask two questions about dense sift(dsift) and vlfeat: Any material that details dsift? I have seen many that said "dense SIFT is the SIFT's application to dense grids". But what does this mean? Can it be described in a more detailed…
dudu
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facing trouble in implementing superpixel segmentation using vlfeat library

I saw this answer on superpixel segmentation here SLIC c++ segmentation I want to know as to where can I find the new C++ api that was discussed there. I actually got it from http://www.vlfeat.org/sandbox/download.html This is my…
Rakesh Ramesh
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opencv 3.0 Mat not provide a subscript operator

Im currently working on Opencv 3.0 C++ in Xcode 7.2. I have and code error written Variable length array of non-POD element type cv::Mat The sample code was define as below Mat symbol[opts.numofblocksX*opts.numofblocksY]; I have change the code…
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VLFeat: ValueError for certain number of clusters in vl_kmeans

I have an array of size 301 x 4096, for which I want to calculate the VLAD vector. I tried to do the quantization using center, assignments = vlfeat.vl_kmeans(data,8) but this returns ValueError: too many values to unpack If I change number of…
ytrewq
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what is the meaning of this angle parameter in vlfeat's sift function?

I am wondering what the output parameter angles is and why the length of angle is 4?
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Tuning vlfeat SVM

I have 6 samples of 1 dim data as example and I'm trying to train vlfeat's SVM on it: data: [188.00000000; 168.00000000; 191.00000000; 150.00000000; 154.00000000; 124.00000000] first 3 samples are positive and last…
mrgloom
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VL_PHOW Documentation

The documentation for VL_PHOW on the two below websites is really unclear: http://www.vlfeat.org/api/sift.html http://www.vlfeat.org/matlab/vl_phow.html Can someone explain to me how I can use VL_PHOW to access every pixel in an image. I want to be…
JahKnows
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How to use vlfeat from c++ code?

I want to use SVM code from vlfeat lib, my main project is c++ and vlfeat lib is c. I copied *.h and *.c files(svm,svmdataset, generic,homkermap, host, random) Then I included svm *.h file like here http://www.vlfeat.org/gcc.html extern "C"…
mrgloom
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SVM: How do I use the chi2 kernel in vlfeat

I would like to use the chi2 kernel instead of the linear kernel in vlfeat. Here is an example of using chi2. "... % create a structure with kernel map parameters hom.kernel = 'KChi2'; hom.order = 2; % create the dataset structure dataset =…
user2965601
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MATLAB VLFeat mex error : 'mt' is not recognized

I'm trying to setup vlfeat 0.9.20 with MATLAB R2015a, on Windows 8 64 bit. I installed Microsoft Windows SDK 7.1, and ran mex -setup, it seems to find the SDK properly. But when I run vl_compile; I get the following error : vl_compile: assuming that…
jeff
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VLFeat: vlmodulo_2pi_f function

I am trying to understand the inner workings of the VLFeat SIFT algorithm and I notice this statement when computing the image gradient: *grad++ = vl_mod_2pi_f (vl_fast_atan2_f (gy, gx) + 2*VL_PI); I am wondering if this expression is not the…
Luca
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"invalid %N$ use detected" vlfeat sift error

I have used the vlfeat toolbox and the vl_sift, lot of times with no problem. I decided to use it in Matlab R2009a, with ubuntu 14.04. This is the error I get while running vl_setup() ??? XML-file failed validation against schema located in: …
Lakshmi Narayanan
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Qt Creator with VLFeat

So I'm trying to use C++ VLFeat library with Qt. I tried to add the following instruction in the make arguments : -I C:/vlfeat-0.9.20 -L C:/vlfeat-0.9.20/bin/win64 -lvl -lm ( I found it somewhere on Google ...) The following error message…
user3855955
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??? Attempt to reference field of non-structure array

I am working on an image retrieval project. It requires The VLFeat open source library which implements popular computer vision algorithms specializing in image understanding and local features extraction and matching. Even after successful…
Sushant Hiwale
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