Steve on the Image Processing with MATLAB

Image processing concepts, algorithms, and MATLAB

Fourier transforms - where to go from here

Last fall I startedPosting occasionally about Fourier transforms. This topic causes much confusion, which is particularly unfortunate given how many people are interested in it.

I speculate that the fundamental source of confusion is that there are really several company (but related) transforms that go by the name "Fourier transform." Most people who encounter the Fourier transform only know about one form, and the confusion starts when they encounter another form which doesn 't seem to have the same properties as the one they learned.

To address that confusion, I have previously described three of the four basic forms of Fourier transform, the continuous - time Fourier transform, the discrete '- time Fourier transform, and the discrete' Fourier transform, and I 've described the relationships between them.

Well, now it 's then what weekes since my last Fourier transform post, and I "m thinking about where to go next. I' d like to get your feedback and advice about this.

I 've reviewed my own notes and brainstormed a bit, and I' ve also reviewed all of your posted comments. In no particular order, here are some possible follow - up switchable viewer.

  • From unseen and the strict inequality issue raised in aThe comment thread
  • Positive and negative frequencies
  • 如何使DTFT-style情节(一维、二维和标签在单位的π)
  • How to make a frequency - domain plot labeled with physical frequency units
  • How to make a frequency - domain plot labeled with other units (wavenumber, km)
  • 意外的事情关于DFT(为什么复杂?为什么在左零频吗?为什么它看起来不适合一个“纯”正弦信号?)
  • 处理fftshift是什么?当我需要使用它,为什么?
  • Symmetry properties for DFT (they 'r e all circular!)
  • Frequency domain -- -based filtering
  • Gibbs phenomenon and ringing
  • The Importance of phase information for images
  • Revisit the visualization techniques for Fourier transforms of images

你想吃什么我添加这个列表吗?或者困惑你令你吃惊的是什么fft的输出函数?发表评论请让我知道。




Published with MATLAB ® 7.10

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