vlfeat | An open library of computer vision algorithms | Computer Vision library
kandi X-RAY | vlfeat Summary
kandi X-RAY | vlfeat Summary
The VLFeat open source library implements popular computer vision algorithms specialising in image understanding and local featurexs extraction and matching. Algorithms incldue Fisher Vector, VLAD, SIFT, MSER, k-means, hierarchical k-means, agglomerative information bottleneck, SLIC superpixes, quick shift superpixels, large scale SVM training, and many others. It is written in C for efficiency and compatibility, with interfaces in MATLAB for ease of use, and detailed documentation throughout. It supports Windows, Mac OS X, and Linux. VLFeat is distributed under the BSD license (see the COPYING file).
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QUESTION
I have installed cyvlfeat using conda install cyvlfeat
( from https://gsoc2016.wordpress.com/2016/08/19/cythonpython-wrapper-for-vlfeat-library-cyvlfeat-project-status/ ).
The problem is that when I run the following code:
ANSWER
Answered 2020-Mar-10 at 15:23The code from the blog post you're trying to use was never merged into the main project: https://github.com/menpo/cyvlfeat/pull/25
As you can see, currently cyvfleat.vlad
is an empty module:
QUESTION
I have a folder of images. I want to compute VLAD features from each image.
I loop over each image, load it, and obtain the SIFT descriptors as follows:
...ANSWER
Answered 2017-May-10 at 07:13First, you need to obtain a dictionary of visual words, or to be more specific: cluster the SIFT features of all images using k-means clustering. In [1], a coarse clustering using e.g. 64, or 256 clusters is recommended.
For that, we have to concatenate all descriptors into one matrix, which we can then pass to the vl_kmeans
function. Further, we convert the descriptors from uint8
to single
, as the vl_kmeans
function requires the input to be either single
or double
.
QUESTION
I have the following Makefile:
...ANSWER
Answered 2020-Feb-28 at 00:31IMO autotools is way overkill for this.
You can do this quite easily. However there are some odd things about your makefile.
Most importantly, all your files are suffixed with a .c
extension which means they are C files, but you are compiling them with g++
which is a C++ compiler. This does not make sense. Either you should be naming your source files as C++ files, which means either .cc
or .cxx
or .cpp
or similar, or you should be using a C compiler like gcc
not g++
.
I will assume your code is C code based on the file extensions.
Please use standard variables (CC
, CPPFLAGS
, CFLAGS
, LDLIBS
):
QUESTION
So basically I am trying to use a pre-trained VGG CNN model. I have downloaded model from the following website:
http://www.vlfeat.org/matconvnet/pretrained/
which has given me a image-vgg-m-2048.mat file. But the guide gives me how to use it in Matlab using MatconvNet Library. I want to implement the same thing in python. For which I am using Keras.
I have written the following code:
...ANSWER
Answered 2019-Nov-16 at 12:32Basically if you specify any weights
which is not imagenet
, it will just use keras model.load_weights
to load it and I guess image-vgg-m-2408.mat
is not a valid one that keras can load directly here.
https://github.com/keras-team/keras-applications/blob/master/keras_applications/vgg16.py#L197
QUESTION
In Keras,
I'm trying to import _obtain_input_shape
as follows:
ANSWER
Answered 2018-Aug-01 at 08:56This issue occured because of the version of keras.
In my case, I was downgrade keras 2.2.2 to 2.2.0, and the problem was solved.
QUESTION
So I'm trying to get into tensorflow and liking it so far.
Today I upgraded to cuda 8, cudnn 5.1 and tensorflow 0.12.1. Using a Maxwell Titan X GPU.
Using the following short code of loading the pretrained vgg16:
...ANSWER
Answered 2018-Sep-07 at 14:53Tested recently on cuda 9.0, tensorflow 1.9 and pytorch 0.4.1, the differences are now negligible for the same operations.
QUESTION
My MATLAB code uses fhog
(instead of Hog) to extract features. However, I want to visualize the HOG features used on the image patch. I know extractHOGFeatures
or VLFeat is used if we use HOG
available in MATLAB. But how do I visualize fhog
?
Since Piotr's Image & Video Toolbox (which has fhog
) is widely used in MATLAB now and I frequently need it, it would be great if someone can tell me how to visualize fhog
extracted features.
The code of fhog can be found at here:
The code snippet is as follows:
...ANSWER
Answered 2018-Jun-25 at 02:26I was able to make this work. It was a stupid thing I was ignoring.
QUESTION
I have extracted DenseSIFT from the query and database image and quantized by kmeans
using VLFeat
. The challenge is to find those SIFT features that quantized to the same visual words and be spatially consistent (have a similar position to object centers). I have tried few techniques:
- using FLANN() on the SIFT (normal SIFT) coordinates on both query and database image and find the nearest neighbor and then comparing the visual words (NOTE: this gave few points that did not work).
- Using Coherent-Point-Drift (CPD) on SIFT coordinates to find the matched points (I am not sure about this whether it is a right solution or not).
I am struggling with it for many days, and I hope experts can guide me with this. What are the possible solutions or algorithms that I can use for solving this?
...ANSWER
Answered 2018-Mar-26 at 22:05Neither of those two methods you mentioned achieve what you want do. The answer depends on the object in your pictures. If it has mostly flat faces, then you can rely on estimating the homography, see this tutorial.
If that's not case then can use the epipolar constraint to remove outliers / get geometrically consistent matches, see this tutorial. There are some other ways to achieve this if the speed is of importance in your application.
QUESTION
I am working on manually converting a pretrained matconvnet model to a tensorflow model. I have pulled the weights/biases from the matconvnet model mat file using scipy.io and obtained numpy matrices for the weights and biases.
Code snippets where data
is a dictionary returned from scipy.io:
ANSWER
Answered 2018-Feb-20 at 03:10I got over this hurdle with tf.reshape(...)
(instead of calling weights['wc1'].reshape(...)
). I am still not certain about the performance yet, or if this is a horribly naive endeavor.
UPDATE Further testing, this approach appears to be possible at least functionally (as in I have created a TensorFlow CNN model that will run and produce predictions that appear consistent with MatConvNet model. I make no claims on accuracies between the two).
I am sharing my code. In my case, it was a very small network - and if you are attempting to use this code for your own matconvnet to tensorflow project, you will likely need much more modifications: https://github.com/melissadale/MatConv2TensorFlow
QUESTION
Im working on a 3d reconstruction project where i have trouble matching the features in order to proceed with the reconstruction. To be more specific when im matching feature of matlab's examples images i have a high correct to wrong matches ratio but when im matching features of my own photos taken by a phone camera i have almost only wrong matches. I 've tried tuning the threshold but the problem still remains. Any ideas/sugestions of what is going wrong?
The descriptor im using is the sift descriptor from the vlfeat toolbox
edit: here is a dropbox link with the original images, the detected salient/corner points and the matches.
...ANSWER
Answered 2017-Jun-17 at 15:19I think your main problems here are significant difference in lighting between the images, and specular reflections off the plastic casing. You are also looking at the inside of the USB drive through the transparent plastic, which doesn't help.
What feature detectors/descriptors have you tried? I would start with SURF, and then I would try MSER. It is also possible to use multiple detectors and descriptors, but you should be careful to keep them separate. Of course, there are also lots of parameters for you to tune.
Another thing that may be helpful is to take higher-resolution images.
If you are trying to do 3D reconstruction, can you assume that the camera does not move much between the images? In that case, try using vision.PointTracker
to track points from one frame into the other instead of matching them.
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