Questions tagged [vlfeat]

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ImportError: No module named vlfeat

I have installed VLFeat on anaconda environment successfully, but once I wanna import it, shows >>> import vlfeat Traceback (most recent call last): File '', line 1, in ImportError: No module named vlfeat Any idea about this? thanks
S.EB
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How to setup VLFEAT on Octave?

The instructions on the official website aren't clear. Does anyone know how to setup VLFEAT on Octave(Windows)?
Aditya Jain
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2

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What's the order of parameters in vl_ubcmatch?

I am using VLFEAT implementation of SIFT to compute SIFT descriptors on two set of images: queries and database images. Given a set of queries, I'd like to obtain the closest descriptors from a big database of descriptors, for which I use vl_ubcmatch. Having vl_ubcmatch syntax as MATCHES = vl_ubcmat...
J Rivera
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View vl_slic output matlab

I feel like this is a fairly simple question but I can't seem to figure it out. I'm trying to use VLFEAT's vl_slic function in MATLAB and I'm using the documentation used at this page: http://www.vlfeat.org/overview/slic.html What I'm having trouble figuring out is how to display and image with the...
user2604504
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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 libsvm is trying to access vl_svmtrain. Is there a...
Cassie
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901

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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 error: Detected compiler: gcc 40800 MATLAB 2014a or great...
Anurag Saran
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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 directory MKOCTFILE toolbox/mex/octave/mexa64/vl...
chibi03
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390

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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 given some features. Everything works fine and I succe...
G4bri3l
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mex error during vl_compilenn

I'm trying to install MatConvNet, as described here. When I run vl_compilenn, I get the following error: >> vl_compilenn Building with 'Microsoft Windows SDK 7.1 (C++)'. MEX completed successfully. % ... repeated many times, then suddenly : Error using mex MEX cannot find library 'gdiplus' specifi...
jeff
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SIFT descriptors values: OpenCV vs VLFeat

I'm trying to compare the SIFT implementation of OpenCV and VLFeat. I noticed that the descriptors value for VLFeat are integers, such as: 0 0 0 0 0 0 0 0 0 0 0 17 45 20 26 0 1 ... While for OpenCV: 0.0391555 0 0 0.0998274 0.235747 0 0 0.0276871 0.156622 ... Notice that these are descriptors for 2...
justHelloWorld
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Memory Limitation when Extracting VLAD from SIFT Descriptors in VLFeat with Matlab

I recently asked how to extract VLAD from SIFT descriptors in VLFeat with Matlab here. However, I am running up against memory limitations. I have 64GB RAM and 64GB Swap. all_descr = single([sift_descr{:}]); ... produces a memory error: Requested 128x258438583 (123.2GB) array exceeds maximum array...
Chris Parry
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Regarding Standard Oxford Format for vlfeat sift

One of my upper classmates has given me a data set for experimenting with vlfeat's SIFT, however, her extracted SIFT data for the frame part contains 5 dimensions. An example is given below: 192 9494 262.08 749.211 0.00295391 -0.00030945 0.00583025 0 0 0 45 84 107 86 8 10 49 31 21 32 37 46 50 11 23...
Karl
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How does VL_SIFT from vlfeat.org work?

I am new to VLfeat implementation of SIFT in Matlab Could someone help/teach me more about how does VL_SIFT from vlfeat.org work? I have read the following link http://www.vlfeat.org/mdoc/vl_sift.html and this document http://www.cs.ubc.ca/~lowe/papers/ijcv04.pdf but I still do not understand how it...
user1943584
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2

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1.7k

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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 I need to do it in C, not Matlab. So how can I cal...
mrmoment
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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 library, so that's where those Matrix data types are comin...
marcman
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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 documentation, if one provides a negative value for the initi...
Luca
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Error coming up while compiling make of vl-feat in ubuntu 16.04

I was put up the make command in the directory of my vl-feat folder and this comes up: /usr/bin/ld: cannot find -liomp5 i have googled enough but unable to track down the problem. Wishing for generous help. Thanks in advance !
Gagan Chaudhary
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I is not a real numeric array of class SINGLE [closed]

I'm using the computer vision: VLfeat library to compute a HOG descriptor of an image, and after inputing this code: cellSize = 8 ; hog = vl_hog(im, cellSize, 'verbose') ; I get this error in MATLAB, and when I google it I really can't find any possible explanation: Error using vl_hog I is not a rea...
Arturo
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1.7k

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OpenCV VLFeat Slic function call

I am trying to use the vl_slic_segment function of the VLFeat library using an input image stored in an OpenCV Mat. My code is compiling and running, but the output superpixel values do not make sense. Here is my code so far : Mat bgrUChar = imread('/pathtowherever/image.jpg'); Mat bgrFloat; bgrUCha...
Frank
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Dsift (vl_feat) and Matlab

I have a (naïve probably) question, I just wanted to clarify this part. So, when I take a dsift on one image I generally get an 128xn matrix. Thing is, that n value, is not always the same across different images. Say image 1 gets an 128x10 matrix, while image 2 gets a 128x18 matrix. I am not quite...
Andr. Ludw.
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C functions with two round brackets pairs?

I'm sorry for the bad title, but nothing better came to my mind apart from 'I don't understand this code'. Please, feel free to propose a modification. I'm reading this code. I've never seen a C function like this one: static void VL_XCAT(_vl_vlad_encode_, SFX) (TYPE * enc, TYPE const * means, vl_si...
justHelloWorld
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Compiling vlfeat mex in octave: undefined symbol

I hope this question is not to specific. I am trying to compile the vlfeat library for octave 3.6.2. It compiles the mex-files without errors. But if I execute vl_setup vl_demo i get error: vl_demo_sift_basic: vl_sift.mex: failed to load: vl_sift.mex: undefined symbol: vl_sift_process_next_octave I...
sietschie
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How to include C library (VLFeat 0.9.21) in iOS Project?

What are the necessary steps I need to take to compile VLFeat (an open source C library) and include it in my iOS project? Here is what I found out so far: I am not too familiar with the compilation and linking procedures, but from what I currently understand, I need to compile VLFeat for the arm64...
crazyshark
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How can I build “C” VlFeat library for Android

I would like to use the 'C' VlFeat (http://www.vlfeat.org/index.html) library for Android. Is there an official build? Is there a simple way for building it? Thanks, Israel Sadeh
user2399151
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vlfeat nmake: fatal error U1073: don't know how to make “msvcr100.dll”

I have downloaded vlfeat source code. I am trying make file using nmake (Microsoft Visual Studio command) to use vlfeat. The command I have given is: nmake /f Makefile.mak ARCH=win32 It gives the following error. NMAKE : fatal error U1073: don't know how to make ''C:\Program Files\Microsoft Visual...
Sridhar Boganathan
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Vlfeat for Ipython

I've been trying to set up vlfeat library for Jupyter which comes with anaconda. I've installed from this https://anaconda.org/menpo/vlfeat but cant import the library in the notebook. Can someone Guide on how to set it up?
user244791
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SIFT orientation normalization

I want to normalize the sift descriptors by rotating them so that the horizontal direction is aligned with the dominant gradient orientation of the patch. I am using vl_feat library. Is there any way in vl_feat to normalize the sift descriptos? or what is the effective way of doing this using matla...
user570593
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VL_SLIC MATLAB Output for VL_FEAT

I am using the VL_SLIC function in MATLAB and I am following the tutorial for the function here: http://www.vlfeat.org/overview/slic.html This is the code I have written so far: im = imread('slic_image.jpg'); regionSize = 10 ; regularizer = 10; vl_setup; segments = vl_slic(single(im), regionSize, r...
Dark Knight
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How does vl_ubcmatch work technically?

I am reading through vl_ubcmatch's function source code, provided here, and I am trying to understand, how does it compute the score, and how does it work technically internally. However, this C code has these macros, weird ## variables like, and what not, that I don't have experience with. So the m...
Karl
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Import Error in __init__.py : No Module named _vlfeat in PyVlfeat

I am trying to run this python rewrite of Vlfeat library. https://github.com/shackenberg/phow_caltech101.py. I am trying to run the application phow_caltech101. This is throwing File '/A/B/C/pyvlfeat-0.1.1a3/vlfeat/__init__.py', line 1, in import _vlfeat ImportError: No module named _vlfeat In the...
Erdnase
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Sift descriptor at particular pixel

I want to find the sift descriptor at a co-ordinate ( x ,y ) in the image with a patch size of 5X5 neighbour with the co-ordinate in the middle. The intention behind it is to analyse the orientation values that I get on that co-ordinate for further processing. Is there any method in matlab that woul...
anon
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Identification of only a part of an image

I want to identify only this marked part in my image. (marked in red) It should be a scale and translation invariant matching algorithm. Which is the best method I can use? Will the SIFT method be useful here? As I have observed, it outputs many points. I want only this predefined part to be identif...
Saania
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Matconvnet error cl.exe not found

I have installed MatConvNet from VLFeat and I am trying to compile it. But as I am trying to run vl_compilenn it shows the following error: vl_compilenn Warning: CL.EXE not found in PATH. Trying to guess out of mex setup. > In vl_compilenn>check_clpath (line 580) In vl_compilenn (line 413) 'cl.exe...
user7029552
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957

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slow kd-tree queries using vlfeat, faster alternatives?

I'm using vlfeat's kdtree which implements the kd-tree from FLANN, which supposedly handles high dimension data. However, right now I have a kdtree built from a 128x15000 set of data and kd tree queries for anything has slowed down to 8 seconds a query. Is this the limit of kd-trees? FLANN was suppo...
mugetsu
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Conversion of Image to Single and Square

I am performing a descriptor function on an image. In the documentation, the function requires me to input image I - I is a gray-scale square image with odd side length of class SINGLE. I already knew how to convert an image matrix to single using single(I), but I am not able to understand what is t...
f3n1Xx
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OpenCV-Python Dense SIFT Settings

This is a follow-up question to the previously posted question about using OpenCVs dense sift implementation in python (OpenCV-Python dense SIFT). Using the suggested code for a dense sift dense=cv2.FeatureDetector_create('Dense') kp=dense.detect(imgGray) kp,des=sift.compute(imgGray,kp) I have the f...
Legie
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372

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Alternative to spatial histograms in Bag of Words approach using vlfeat

The phow_caltech101 demo app in vlfeat creates a complete Bag of Words process for image classification on the Caltech101 dataset, roughly put: Feature Extraction Visual Vocabulary building Spatial Histograms computation SVM training SVM testing and evaluation, obtaining a model that can be used to...
Rolo Villa
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How to ensure consistency in SIFT features?

I am working with a classification algorithm that requires the size of the feature vector of all samples in training and testing to be the same. I am also to use the SIFT feature extractor. This is causing problems as the feature vector of every image is coming up as a different sized matrix. I kno...
StuckInPhD
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658

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Extract HOG from a single pixel using VLFEAT

I'm trying to extract points of interest to perform an image registration of clinical images. I've detected MSER from an image 'I' using vl_mser: [R, F] = VL_MSER(...) which returns a region of seeds R and ellipsoids F. Now I would like to calculate Hog from the ellipsoids' center using vl_hog. Howe...
bongini.simone
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132

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VLFeat SIFT descriptor

I'm reading this code about how to extract SIFT features using VLFeat. In particular the descriptor relative to the keypoint key with direction angles is saved in f.desc: vl_sift_calc_keypoint_descriptor(filt, &f.desc[0], key, angles[q]) ; BOOST_FOREACH(float &v, f.desc) { /* v = round(v * SIFT_RANG...
justHelloWorld

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