Questions tagged [surf]

Speeded-Up Robust Features (SURF) is a feature detection algorithm used in many [tag:computer-vision] tasks, such as object recognition, 3D reconstruction, camera calibration, and [tag:cbir].

Speeded-Up Robust Features (SURF) is an algorithm in computer vision to detect and describe local features in images.

SURF is billed as specifically “Speeded-Up” and “Robust” over its predecessor, the SIFT algorithm – it is based on Hessian blob detection, and eschews the more byzantine arrangements of SIFT (e.g. octaves). This visualization illustrates SURF features with circles, scaled accordingly for each feature, overlaid on the image from which they were extracted:

SURF feature overlaid

The standard standard SURF implementation, from the introductory journal article, is about an order of magnitude faster than David Lowe’s implementation of SIFT (when run in a comparable environment).

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Descriptor evaluation for SURF opencv

I'm doing a project on SURF and so far I have implemented SURF features successfully, and I have done the feature evaluation correctly as well. But I don't know how to do the DESCRIPTOR evaluation... I'm using c++/opencv svn. Here you can find the…
Mario
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Feature/blob correlation and histogram analysis

I'm working on a sketch search engine that correlates whatever someone's sketching with a picture in the database (the db is just about 40 pictures now). I'm doing this mostly for fun so I'm not that well-versed in computer imaging techniques. First…
David Titarenco
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Retrieving the most significant features gained from SIFT / SURF

I'm using SURF to extract features from images and match them to others. My Problem is that some images have in excess of 20000 features which slows down matching to a crawl. Is there a way I can extract only the n most significant features from…
Darcara
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Defining surfaces not just in terms of z

I have three different surfaces and I want to display all of them in one figure. The problem is, that I have one surface defined in terms of z (means that I got x and y values and a grid which specifies the z-values for each combination) and two…
gumpel
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How to get a beautiful color scale on (semi-)logarithmic 3d plots on Matlab?

After having this question answered through a link to an external site, I realized that I solved a problem, just to get another one: On a logarithm scale the C=Z parameter of MESH and SURF functions don't work very well. All you get is a blue graph,…
Jader Dias
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Plot surface from irregular data

I'm make a filled contour or surface plot from a scattered dataset. A major difference from other Qs is that the data are not convex. [r,th] = meshgrid(10:15,0:180); [x,y] = deal(r.*sind(th), r.*cosd(th)); z =…
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How to visualize a 3d scene using surf

I have an image loaded from disk as a texture, and a same-sized matrix d which has the corresponding depths. How can I use surf to show me the image as a 3d-model? Simply taking surf(depthMatrix, img); doesn't give a nice result since the camera…
Etan
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Error reading images using imread OpenCV

I am comparing two images using findHomography(). I have added extra modules from opencv_contrib in OpenCV 3.1.0 to use Surf and Sift algorithms and to compile for latest Android architectures. I can successfully compile the libraries using…
Shahzeb
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Filling an area above a curve with many colors (matlab, surf)

I'm trying to create a figure in matlab that looks like this: desired figure I am doing so by: (i) assigning value points to each x,y coordinate, (ii) plotting a surf, and (iii) change the view point so the third axis is not seen. Here is the code: …
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Matlab: Colorbar in GUIDE

I have been trying for a while to input a colorbar beside my contour maps in guide with no luck. axes(handles.firstcontouraxes); contourf(Y,X,z1) title('First population'); set(gca,'YDir',yinverse,'XDir',xinverse,'clim',[cmin cmax]); colorbar The…
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how to improve orb feature matching?

I am trying to register two binary images. I used opencv orb detector and matcher to generate and match feature points. However, the matching result looks bad. Can anybody tell me why and how to improve? Thanks. Here are the images and matching…
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Feature extraction of 3D image dataset

Assume a workflow for 2D image feature extraction by using SIFT, SURF, or MSER methods followed by bag-of-words/features encoded and subsequently used to train classifiers. I was wondering if there is an analogous approach for 3D datasets, for…
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How can I use features SURF/ORB/... to detect object with brightness-invariant?

How can I use one of feature types to detect object - illumination / brightness invariant? Interested to use features that resistant to: different lighting half of the object in the shadow glare/reflections Does it make sense to use a HUE (1st…
Alex
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Emgu CV Surf picture detection against known database?

I'm trying to compare an image against a known set of images and find the closest match(es) using Emgu CV and Surf. I've found a lot of people trying to do the same thing but not a complete solution that uses the GPU for speed. The closest I've…
znelson
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How to create an authentication free aikau webscript in Share

I have the need to create a page in the Alfresco Share context that should be accessible without authentication. When using the page framework it seems pretty straight forward since you can add none to the page…
billerby
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