mholecy's profile - activity

OpenCV doesn't want any of these parameters. At least not in Java interface. I just choose detector and descriptor method (SIFT or SURF) and then match their descriptors.

No, in average SURF keypoints return many 0 octaves, few 1 and very few 2 octaves. On the other hand SIFT returns big octave numbers with seven and eight digits. As far as I know SIFT and SURF is implemented in OpenCV according to patent and can be used for free for non-commercial use only. So it should be the same as original, or am I wrong ?

Nope, SIFT process even more features than SURF. My results: SURF: 269 667 features in 98,038 seconds SIFT: 336 437 features in 55,27 seconds

I'm working on my thesis and I measured times it takes for each algorithm SIFT and SURF to find a match. I know that SURF was designed to be faster than SIFT, but my measures revealed the opposite. The measure test is running with 20 images from very small to very big, from black and white to very colorful. The tests show, that SIFT is twice as fast as SURF I'm using OpenCV-2.4.8 with Java interface and FLANNBASED descriptor matcher. I'm not the only one who notice this, for example here is another one, but without answer: link

How can I explain this in my thesis ?

Lucky Luke thank you for marvelous answer. My application is more responsive than ever.

I'm developing an application using Java Opencv-2.4.4 and swing GUI. Problem is that I'm unable to find any solution, that shows efficient way how to print processed image (saved in Mat object) to java swing GUI. For this moment I'm using this clumsy solution:

javax.swing.JLabel outputImage;
outputImage.setIcon(new javax.swing.ImageIcon("/home/username/Output.png"));

private void sliderStateChanged(javax.swing.event.ChangeEvent evt) { 
       .
       .
  Mat canny; // Here is saved what I want to plot
  String filename = "/home/username/Output.png";
  Highgui.imwrite(filename, canny);  // write to disk
  outputImage.setIcon(new ImageIcon(ImageIO.read(new File(filename)))); //update Icon
       .
       .
}

When user changes some values, inputs etc .., in GUI I have to overwrite Output.png on disk and then update jLabel with new image from disk.

Is there any more elegant / efficient solution to this ? Is it posible to plot or convert Mat object directly to Canvas or Image or anything that is printable as image in swing ?