• Filtering fun

    Updated: 2011-07-22 15:12:21
    Today I want to take the test pattern I created last time and subject it to a variety of frequency-based filters. In this post I'll be using a variety of frequency design and frequency-response visualization tools in MATLAB, Signal Processing Toolbox, and [...]

  • Jähne test pattern - take 3

    Updated: 2011-07-19 21:50:18
    Earlier today I told you that I was feeling a little dense because I couldn't figure out the right parameters to use in the tanh term of this test pattern: (This is equation 10.63 in Practical Handbook on [...]

  • Jähne test pattern - take 2

    Updated: 2011-07-19 14:18:38
    Last week I talked about the so-called Jähne test pattern and how I found a description of it in Practical Handbook on Image Processing for Scientific Applications, by Bernd Jähne, CRC Press, 1997. This equation was given in the book: And here's a [...]

  • Measuring elapsed time in MATLAB

    Updated: 2011-07-18 12:46:14
    The July 2011 issue of MATLAB Digest is out, and an article by Martin Knapp-Cordes and Bill McKeeman caught my eye. It describes improvements to the MATLAB tic and toc functions. It also describes some general principles and specific techniques associated with trying to measure elapsed time in standard seconds on a computer. It turns [...]

  • Jähne test pattern

    Updated: 2011-07-16 14:21:21
    Earlier this week I posted a summary of posts from the beginning of this blog, including my January 13, 2006 post on generating test images. Today I want to revisit one of the examples from that old post. In my 2006 post I showed this test image, [...]

  • Five years ago: January and February 2006

    Updated: 2011-07-13 12:57:54
    It's hard for me to believe, but I started writing this blog just over five years ago. I'm going to start occasionally recapping old blog posts, especially those with content that is still useful today and that more recent readers may not have seen. [...]

  • MATLAB R2011a

    Updated: 2011-06-09 04:39:42
    R2011a shipped back in April, but I haven't said too much about it, yet. I mentioned the new geotiffwrite function in Mapping Toolbox (18-Apr-2011 post), and I discussed the improved performance of certain kinds of automatic array growth in MATLAB (16-May-2011 and 20-May-2011 posts). For new MATLAB [...]

Current Feed Items | Previous Months Items

Jun 2011 | May 2011 | Apr 2011 | Mar 2011 | Feb 2011 | Jan 2011