http://www.kerrywong.com Sat, 04 Jul 2009 01:06:30 +0000 http://backend.userland.com/rss092 en In my previous three articles (1,2,3) I discussed how to use Canny edge detection and Hough transform to identify blur images. Here I will show some results from the algorithm discussed before. Results When presented with images that are clear, the algorithm correctly identified most of them (see images below): [caption id="attachment_1285" align="aligncenter" ... http://www.kerrywong.com/2009/07/03/image-blur-detection-via-hough-transform-iv/ I will continue where I left off in my previous post. After performing Hough transform, and extracted the longest sections of lines for each corresponding Hough line detected, we will need to calculate the gradients of the image pixels luminance around the line sections. Gradient Calculation If you remember how the Hough ... http://www.kerrywong.com/2009/06/27/image-blur-detection-via-hough-transform-iii/ In my previous post, I briefly discussed the rationale behind automated blur detection in digital imagery and did an overview of an algorithm that could be used to detect blur images. Here I will show some implementation details along with some C++ code snippets. Experience tells us that blur images tend ... http://www.kerrywong.com/2009/06/24/image-blur-detection-via-hough-transform-ii/ It is often necessary to identify and classify images based on their clarities. For instance, it is desirable for an automated process to locate blurred images within a large digitized image library and then automatically sharpen the blurred images via inverse filtering or blind deconvolution. In the following series of ... http://www.kerrywong.com/2009/06/19/image-blur-detection-via-hough-transform-i/ I was trying to search for some code examples on how to do a recursive directory search under Linux using C++ the other day. But to my surprise, I could not find any place that offers a complete example. So I decided to post my code here after I created ... http://www.kerrywong.com/2009/06/12/c-recursive-directory-search-under-linux/ Getting LaTex style math equations to work in WordPress is actually pretty easy. I followed the advice here and everything seemed to work pretty well. Besides installing wp-hooks and jsMath I also installed jsMath fonts so that I don't have to rely on end users having the correct font installed in ... http://www.kerrywong.com/2009/06/04/latex-math-equations-in-wordpress/ So Microsoft's new search engine Bing has been available for the general public for a few days. While I have read about Bing here and there, I decided to do some comparison myself between Bing and Google. The Homepage Depending on who you ask, you either love Google's minimalist search home page ... http://www.kerrywong.com/2009/06/02/my-first-few-days-with-bing/ Measuring the execution time for code sections can be done in multiple ways in C++. Except for the time resolution issue, different timing methods worked relatively the same in single processor environment. As multi-core processors become more prevalent however, we need to be careful at choosing the correct timing mechanism ... http://www.kerrywong.com/2009/05/28/timing-methods-in-c-under-linux/ As I wrote last time, I did a clean Ubuntu 9.04 install on my main PC. Everything worked pretty well. But after re-installing all the packages I needed for C++ development, I realized that I still was missing some libraries as I got "Magick::ErrorMissingDelegate" exception (ImageMagick: no decode delegate for ... http://www.kerrywong.com/2009/05/20/magick-missing-delegate-error/ Last month,I upgraded one of my PCs from Ubuntu 8.10 to Ubuntu 9.04 and everything went rather smoothly. Since my main PC is running Ubuntu 8.04 (LTS) and there is no option to upgrade to 9.04 directly without going through 8.10, so I decided to try a fresh installation. I have ... http://www.kerrywong.com/2009/05/13/ubuntu-904-on-my-main-pc/ OK, I admit I was not quite prepared for the traffic I got for my previous post on MS-DEBUG as my website has been overwhelmed by the flood of requests coming in. Yes, I got Slashdotted! Apparently, I do not have enough memory on the server and the large volume ... http://www.kerrywong.com/2009/05/09/got-slashdotted/ Earlier this week (May 5) Microsoft Windows 7 Release Candidate was released to the general public and like many technology enthusiasts I downloaded a copy early in the morning hours on Tuesday, shortly after Microsoft made it available on its website. The RC build of Windows 7 (build 7100) has many ... http://www.kerrywong.com/2009/05/08/ms-debug-1981-2009/ In the example I gave in "Interfacing IPP with Magick++", I illustrated how to use Intel’s Integrated Performance Primitives (IPP) to perform edge detection. One issue with Canny edge detection algorithm is that we need to specify a high threshold and a low threshold. How to select those threshold values ... http://www.kerrywong.com/2009/05/07/canny-edge-detection-auto-thresholding/ I was traditionally a KDE user till KDE 4.0 came along. While many users are excited about many of the new features (e.g. Widgets) added in KDE 4, I am simply no big fan of fancy user interfaces. So I have been using GNOME ever since. Of course the beauty ... http://www.kerrywong.com/2009/05/01/kbuntu-904-test-drive/ Without much fanfare, Ubuntu 9.04 (Jaunty Jackalope) was released into the wild earlier today. But Ubuntu followers are wasting no time, overloading many of the official downloading sites. This kind of enthusiasm is certainly encouraging as Linux matures. And certainly, this kind of enthusiasm is much needed for the open ... http://www.kerrywong.com/2009/04/23/the-jaunty-jackalope/ So far I have been mainly using KDevelop and Code::Blocks as my C++ development IDEs. Recently, I started using NetBeans IDE for C++ and I started to like it quite a bit. In my opinion, the above three IDEs all have their strengths and weaknesses depending on what kind of project ... http://www.kerrywong.com/2009/04/18/c-ides-under-linux/ I had set up my apt-get source to use latest SVN build of Code::Blocks. Everything has been running pretty smoothly until a couple of days ago when Code::Blocks was updated to SVN 5534. It seemed that for whatever reason, this particular build is extremely unstable on my Ubuntu 8.04 box ... http://www.kerrywong.com/2009/04/15/how-to-revert-to-a-specific-svn-version-of-codeblocks/ If there is any thing I think Linux distributions can definitely improve upon is to reduce the default IO task priorities while running a Windows manager (e.g. GNOME or KDE). What I have found out over time is that the default IO priorities tend to cause the UI very sluggish when ... http://www.kerrywong.com/2009/04/14/on-default-linux-io-priority/ A couple of weeks ago, I wrote about how to interface Integrated Performance Primitives (IPP) with Magick++. While IPP offers excellent performance advantages, it does not come with the easiest programming model. Fortunately, it is easy enough to create a C++ wrapper on top of IPP and provide an easier ... http://www.kerrywong.com/2009/04/10/an-image-class-based-on-ipp/ After I upgraded to the latest SyntaxHighliger (2.0.296) I noticed that the font size of the code section is a little bit too small to my taste. But there is not an UI option to change it. So I went to the source code and located the style sheet where the ... http://www.kerrywong.com/2009/04/05/changing-syntaxhighlighter-font-size/