• Shuffling label colors

    Updated: 2012-05-16 03:19:00
    I've written often here about various computational and visualization techniques involving labeling connected components in binary images. Sometimes I use the function label2rgb to convert a label matrix into a color image with a different color assigned to each label. Here's an example.bw = imread('http://blogs.mathworks.com/images/steve/2012/rice-bw.png'); imshow(bw) Now compute the connected components and the corresponding label [...]

  • The DFT matrix and computation time

    Updated: 2012-05-01 23:06:59
    On my list of potential blog topics today I saw just this cryptic item labeled dftmtx. Hmm, the MATLAB dftmtx function. But have I written about this function before? I better double-check by searching the old blog postings: Oh, I forgot about Loren's post! She showed how the discrete Fourier transform, which MATLAB users normally [...]

  • And now for something completely different

    Updated: 2012-04-11 01:00:40
    The following video spread up and down the MATLAB Math team's hallway like wildfire yesterday: http://www.youtube.com/watch?v=ywWBy6J5gz8 I said there was some room for improvement because I thought the last 20 seconds or so of the algorithm could be optimized away. However, math developer Bobby informed me that those last few dance steps are necessary to [...]

  • imzoneplate on the File Exchange

    Updated: 2012-04-10 01:45:46
    Last year I posted a few times about the "Jähne test pattern," something that readers then told me was called a zone plate. This is a radial sinusoid pattern with low frequency in the middle of the image and high frequency toward the edges: In my 02-Jul-2012 post, Filtering fun, I used the zone plate [...]

  • Bug reports on mathworks.com – “Fixed in R2012a”

    Updated: 2012-04-06 01:00:51
    Do you want to know what bugs have been fixed in R2012a for your favorite products? Are you looking for a workaround for a bug? Try visiting the "Bug Reports" section of mathworks.com. Start by clicking on Support. Then click on Bug Reports. To find out which bugs have been fixed in R2012a in the [...]

  • MATLAB R2012a

    Updated: 2012-04-03 01:00:28
    Some of my fellow MATLAB Central bloggers have already talked about the MATLAB R2012a release. Usually, I like to scan the release notes and pick out just a few things that particularly interest me. I encourage you to take a look at the release notes to see what else is there that might interest you. [...]

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