Dealing with images Java can’t handle out of the box

March 8, 2021 on 10:43 am | Tags: , , , , | In General, Java, Software | No Comments

Frequently asked question in the mailing list is: Lire cannot handle my images, what can I do? In most cases it turns out that Java can’t read those images and therefore the indexing routine can’t create a pixel array from the file. Java is unfortunately limited in it’s ability to handle images. But there are two basic workarounds.

(1) You can convert all images to a format that Java can handle. Just use ImageMagick or some other great tool to batch process yout images and convert them all to RGB color JPEGs. This is a non Java approach and definitely the faster one.

(2) You can circumvent the metzhod by using ImageJ. In ImageJ you’ve got the ImagePlus class, which supprts loading and decoding of various formats and is much more error resilient than the pure Java SDK method. Speed, however, is not increased by this approach. It’s more the other way round.

Find some code example on how to do this in the wiki.

Extracting SURF features – convenience command line utility for Windows

March 2, 2021 on 4:36 pm | Tags: , , | In Dev, General, Multimedia, Software | No Comments

Sometimes you just need a small command line utility to extract some local feature from an image … and you have no time to set up and compile OpenCV right this time. Here’s the solution: I did the task (actually for my students and for me, but still you might use it :) .

The utility is absolutely basic stuff. Just start “extractSurf.exe” on Windows 7, give it an image as first parameter and it will spit out the surf feature descriptors (on stdout) headed by the x and y coordinates and the response value. Source - of course - is also provided … but it’s not magic. It’s all about the convenience of the binary.

Links to the OpenCV wiki on how to compile the stuff are provided in a small README in the source archive.


  • extractSurf-bin.7z - (7Z archive, Win7 32 bit binary, 1.5M)
  • extractSurf-src.7z - (7Z archive, C++ code and CMake file, 1.2K)

Nice but out of reach: popular multimedia platforms

March 1, 2021 on 3:49 pm | Tags: , , , , | In General, Multimedia | 1 Comment

Netflix was reported last year to be the source of nearly 30% of the North American internet backbone traffic. Well that’s impressive, but that’s something that many non North Americans can’t understand … and there’s a simple reason for that: the service is not available in many countries. Several well known and well received services are restricted to a range of IP adresses that are considered in a geographic location where users have access to this services. Here is a small but still interesting list of services that have obviously impact on the usage of the internet, but cannot be accessed in many European countries.

  • Netflix - major video streaming service (subscription based)
  • Pandora - music streaming service / adaptive online radio (ad supported)
  • Hulu - major video streaming service of already aired TV content (ad supported)
  • Vevo - music video streaming service (ad supported). Most of the music videos on Vevo are available on YouTube for Austrians, but most of these music videos are not accessible of Germans.
  • NBC - video streaming service of already aired NBC TV content.
  • ABC - video streaming service of already aired ABC TV content.


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