Rank: 42 based on 806 downloads (last 30 days) and 12 files submitted
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Theodoros Giannakopoulos

E-mail
Company/University
Computational Intelligence Lab @ Demokritos . gr
Lat/Long
37.96795272827148, 23.76673698425293

Personal Profile:

Theodoros Giannakopoulos received his diploma of Informatics and Telecommunications in the University of Athens (2002), M.Sc. of SIPS ("Signal and Image Processing Systems), organised by University of Patras (2004) and his PhD in the field of audio analysis (University of Athens, 2009).

He is currently a research associate in
- Computational Intelligence Laboratory (CIL) of the Institute of Informatics and Telecommunications (National Center for Scientific Research "DEMOKRITOS", Greece)
- the Dpt of Informatics and Telecommunications in the University of Athens .

WEB PAGE: http://www.di.uoa.gr/~tyiannak

Professional Interests:
Signal Processing, Pattern recognition, audio classification, content-based multimedia indexing.

 

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Files Posted by Theodoros View all
Updated   File Tags Downloads
(last 30 days)
Comments Rating
12 Sep 2012 Screenshot Image Processing GUI A simple GUI with basic image processing functionalities. Author: Theodoros Giannakopoulos image processing, gui, color filtering, moion filtering 196 5
  • 4.0
4.0 | 1 rating
24 Sep 2010 Screenshot Silence removal in speech signals A simple method for silence removal in speech streams Author: Theodoros Giannakopoulos audio, speech, speech analysis, signal processing 115 2
  • 5.0
5.0 | 3 ratings
24 Feb 2009 Screenshot Generate report of .m files in html table Generates a report of the m-files in a given directory. Results are stored in an html file. Author: Theodoros Giannakopoulos matlab documentation, misc, help 2 2
  • 4.0
4.0 | 1 rating
08 Nov 2008 Screenshot Image retrieval - Query by Example Demo This demo provides a simple query by image example method, based on HSV values. Author: Theodoros Giannakopoulos color, image analysis, image retrieval, query by example 141 33
  • 4.2
4.2 | 16 ratings
20 May 2008 Screenshot Generate Animated GIF Files for Plotting Audio Data This m-file generates a animated GIF file that visualizes audio data. Author: Theodoros Giannakopoulos audio processing, video processing, audio visulization, animated gif, audio data, signal processing 16 1
  • 5.0
5.0 | 1 rating
Comments and Ratings by Theodoros View all
Updated File Comments Rating
19 Apr 2013 mmread Read virtually any media file in Windows, Linux, or Mac. Author: Micah Richert

Really nice work! Though, I have the following problem. When reading frames from a large video file and the function seems to be rather slow for large frame indeces. E.g
video = mmread('/home/tyiannak/Desktop/05-10-19.avi', [10000]);
runs for several seconds. I suppose this is due to some type of file seeking. Can I avoide this?
Regards,
Theodore

14 Mar 2013 Silence removal in speech signals A simple method for silence removal in speech streams Author: Theodoros Giannakopoulos

Dear Nikolay. First of all thank you for your comments. Some notes on them:
(a) mp3 IO was not supported in older Matlab versions. Furthermore, audioread seems to have some OS compatibility issues, so I stuck with WAV file format only. Personally, I prefer to use some extrernal script for transcoding (e.g. commandline ffmpeg...)
(b) optioned listening seems right to me to: I will change this in the future
(c) GUI is also some fututre plan
(d) It's true that the precision / recall is not 100%: this is due to the very simple audio features adopted. One can rely to more sophisticated features for better results (e.g. mfccs, other spectral features etc).
I'd be glad to see your new results using and expanding this algorithm.
Again, thank you for your comments!
Theodoore

24 Mar 2011 mmread Read virtually any media file in Windows, Linux, or Mac. Author: Micah Richert

I've just downloaded your code and used it for reading mpeg files in Matlab. The fact that is worked without any problems on Ubuntu is really good, so ... thank you!

15 Feb 2011 Image Processing GUI A simple GUI with basic image processing functionalities. Author: Theodoros Giannakopoulos

Hi Sam. Thank you for your question. This is quite simple actually. You only need to add a button and then use the imrotate function (http://www.mathworks.com/help/toolbox/images/ref/imrotate.html). I am uploading an updated version which provides you the ability to rotate an image (rotate angle is selected in the range 0.360 using a slider).

03 Feb 2011 Image retrieval - Query by Example Demo This demo provides a simple query by image example method, based on HSV values. Author: Theodoros Giannakopoulos

Hi MUKUND SARDA, thank you for your interest. There is a quite detailed description of the algorithm above. In general the idea is quite simple: an empirical measure is defined on the thresholded distances of the HSV feature space. Then this similarity measure is sorted for returning the closest images. If you have any particular questions, please feel free to ask.

Comments and Ratings on Theodoros' Files View all
Updated File Comment by Comments Rating
20 Apr 2013 Image retrieval - Query by Example Demo This demo provides a simple query by image example method, based on HSV values. Author: Theodoros Giannakopoulos Joel

This program uses Euclidean Distance to compare the similarities. Instead can someone change the code to compute the similarities as one of the following please.

Canberra Distance or City Block Distance

http://stn.spotfire.com/spotfire_client_help/hc/hc_city_block_distance.htm

http://en.wikipedia.org/wiki/Canberra_distance

20 Apr 2013 Manual Audio Annotation AudioAnnotation Demo v.1.0 is an open source demo implemented in Matlab(R) for manual segmentation a Author: Theodoros Giannakopoulos Today

Hi,I don't know why there are some errors in "set(handles.infoFile, 'String', fileName);" which called "Attempt to reference field of non-structure array.".

15 Apr 2013 Histogram-based class separability measure The provided functions demonstrate a histogram-based measure for class separability, given the sampl Author: Theodoros Giannakopoulos Palaniappan, RAJKUMAR

14 Mar 2013 Silence removal in speech signals A simple method for silence removal in speech streams Author: Theodoros Giannakopoulos Giannakopoulos, Theodoros

Dear Nikolay. First of all thank you for your comments. Some notes on them:
(a) mp3 IO was not supported in older Matlab versions. Furthermore, audioread seems to have some OS compatibility issues, so I stuck with WAV file format only. Personally, I prefer to use some extrernal script for transcoding (e.g. commandline ffmpeg...)
(b) optioned listening seems right to me to: I will change this in the future
(c) GUI is also some fututre plan
(d) It's true that the precision / recall is not 100%: this is due to the very simple audio features adopted. One can rely to more sophisticated features for better results (e.g. mfccs, other spectral features etc).
I'd be glad to see your new results using and expanding this algorithm.
Again, thank you for your comments!
Theodoore

12 Mar 2013 Silence removal in speech signals A simple method for silence removal in speech streams Author: Theodoros Giannakopoulos S., Nikolay

Excellent submission, works fine on the example, and additional files. Almost what I was looking for. Luckily I’ve checked the File Exchange before I’ve written a version of my own. In my case I’m interested in removing silence gaps form several hours recording from some sort of an audio surveillance device. This way I wish to save listeners time and storage space. A few comments, if I may:
• Why limiting the supported file formats to .wav? “audioread” supports MP3 and many other common audio formats.
• For my case I am not always interested to listen to the segments with voice/audio data, though I’d like to have the option.
• I am interested is storing relevant segments, ignoring silence gaps and irrelevant segments. This naturally demands some dialogs and GUI.
• I’ve noted sometimes speech is not properly detected, I’m still investigating this...
I plan to work on your code, to shape it into the application I want (which is a bit different from the current functionality). As mentioned above your code is an excellent starting point. If you want to, I can share the results later on, perhaps even submitting it.
Keep up the good work!
Thanks!

Top Tags Applied by Theodoros
audio processing, video processing, audio, color, image processing
Files Tagged by Theodoros View all
Updated   File Tags Downloads
(last 30 days)
Comments Rating
12 Sep 2012 Screenshot Image Processing GUI A simple GUI with basic image processing functionalities. Author: Theodoros Giannakopoulos image processing, gui, color filtering, moion filtering 196 5
  • 4.0
4.0 | 1 rating
24 Sep 2010 Screenshot Silence removal in speech signals A simple method for silence removal in speech streams Author: Theodoros Giannakopoulos audio, speech, speech analysis, signal processing 115 2
  • 5.0
5.0 | 3 ratings
24 Feb 2009 Screenshot Generate report of .m files in html table Generates a report of the m-files in a given directory. Results are stored in an html file. Author: Theodoros Giannakopoulos matlab documentation, misc, help 2 2
  • 4.0
4.0 | 1 rating
08 Nov 2008 Screenshot Image retrieval - Query by Example Demo This demo provides a simple query by image example method, based on HSV values. Author: Theodoros Giannakopoulos color, image analysis, image retrieval, query by example 141 33
  • 4.2
4.2 | 16 ratings
20 May 2008 Screenshot Generate Animated GIF Files for Plotting Audio Data This m-file generates a animated GIF file that visualizes audio data. Author: Theodoros Giannakopoulos audio processing, video processing, audio visulization, animated gif, audio data, signal processing 16 1
  • 5.0
5.0 | 1 rating

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