View License

Download apps, toolboxes, and other File Exchange content using Add-On Explorer in MATLAB.

» Watch video

Highlights from
Keypoint Extraction

4.8 | 14 ratings Rate this file 70 Downloads (last 30 days) File Size: 343 KB File ID: #17894 Version: 1.0
image thumbnail

Keypoint Extraction


Vincent Garcia (view profile)


05 Dec 2007 (Updated )

Extract image keypoints using most common algorithms.

| Watch this File

File Information

The current directory contains functions allowing to extract keypoints also called "feature points", "corners", "interest points", etc. The following algorithm are provided :
- Harris
- Harris-Laplace
- Laplacian of Gaussian (LoG)
- Gilles
The input image must be a gray level image. The output is a matrix of dimension Nx2 or Nx3 with N the number of keypoints extracted. The first column gives the row poisition of the keypoints and the second column gives the column position of the keypoints. The third column gives the feature scale of the keypoints. This scale corresponds to the radius of the local neighborhood to consider. Note that the SUSAN algorithm is a contribution of Joaquim Luis.

Run the test function to see an example.

The picture "door" was taken by Aleksandra Radonic'.
The picture "sunflower" was taken by Candy Torres.
The picture "patrol" was taken by Markus Schöpke.


This file inspired Feature Points In Image, Keypoint Extraction.

MATLAB release MATLAB 7.5 (R2007b)
Other requirements The SUSAN algorithm works under Windows
Tags for This File   Please login to tag files.
Please login to add a comment or rating.
Comments and Ratings (22)
31 Jan 2017 Fatma Elzahraa Ahmed

Is it right to input a vector to the kp_log? Actually, I did that and obtained N*3, where first column in the row in the input, the second column is always 1 (because the input is vector( and the third column contain numbers (scales as mentioned here). Are the obtained results are logical?

Comment only
18 Nov 2016 xin guowang

@ vincent Excellent work!thanks!but how to get susan program?

18 Nov 2016 xin guowang

18 Nov 2016 xin guowang

11 Mar 2016 zhou kangpeng

12 Mar 2013 tamanna

@ vincent but susan is not working here. how can i extract keypoints using susan

Comment only
04 Feb 2013 Moo

Moo (view profile)

14 Jan 2013 Yan

Yan (view profile)

24 Feb 2012 Wajahat

Excellent. Many thanks

Comment only
03 Jul 2011 Yang

Yang (view profile)

hi good job,I want to change the code to extract the point with the plot function,that maybe used plot(r,c,'r+'),so how can I change it?thank you!

Comment only
23 Jun 2011 Yang

Yang (view profile)

how to download?

Comment only
22 Mar 2011 Xin Li

Xin Li (view profile)

It will be perfect if the user could control the number of the output key points on some level.

30 Dec 2010 Maxime

Maxime (view profile)

Great job!

I found that replacing imfilter(img,...) by imfilter(single(img),...) significantly speeds up the detection of keypoints. This is especially interesting with kp_log for which the time decreased from several minutes to 10 seconds in my case. This is due to the available Intel IPP library (as mentioned in the doc of imfilter).

07 Dec 2010 Dariush

Great job,, I have a question,,,
The output give some keypoints of the input image, how can I extract the features of the image from ONLY THESE SELECTED KEYPOINTS?

04 Nov 2009 Vincent Garcia

Vincent Garcia (view profile)

Hi Zhu and hi all,
I found the Gilles' PhD thesis on Internet but I unfortunately don't have the adress.

Comment only
02 Nov 2009 Raymond Cheng

Thanks for your sharing.

10 Jun 2009 Zhu Johnny

Vincent, thank you for your excellent work, Can you tell me where can I get S Gilles' PhD thesis? I wanna learn how the Gilles algorithm works in detail

25 Sep 2008 Daniel Schleicher


25 Feb 2008 zenith tan

can i use subplot instead of draw ?

thx !

25 Feb 2008 zenith tan

its an excellent piece of work

06 Dec 2007 Vincent Garcia

Actually, in my first submission, the SUSAN algorithm was not used (I had just forgotten to remove the susan.dll file). Now, I add the SUSAN algorithm wich is a contribution of Joaquim Luis. I hope you will enjoy my (our) contribution.

Comment only
05 Dec 2007 Joaquim Luis

Vincent, It seams that you are using my "susan" submission. No problem with it but you should acknowledge it and by that way users would know where to get the source code.
Also, why are you terminating functions with an "end"?

Comment only
06 Dec 2007

I add the SUSAN algorithm provided by Joaquim Luis

06 Dec 2007

Modification of description

06 Dec 2007

Remove the Thumb file added by Windows

Contact us