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23 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is a basis set? |
A basis B of a vector space V is a linearlyindependent subset of V that spans V. (Ex a set of orthogonal vectors that add to V, but doesn't have to be orthogonal) |
2C-L1 |
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What would be a good basis set for image analysis? |
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2C-L1 |
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What is a Fourier Series? |
A periodic function represented as a summation of sines and cosines. |
2C-L1 |
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What is the Fourier Transform of an impulse? |
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2C-L1 |
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What is the formula for a one dimensional discrete Fourier Transform? |
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2C-L1 |
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What's the formula for a two dimensional continuous Fourier Transform? |
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2C-L1 |
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What's the formula for a two dimensional discrete Fourier Transform? |
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2C-L1 |
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What do even and odd frequency spectra look like? |
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2C-L1 |
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What would a sinusoid magnitude mapping look like? |
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2C-L1 |
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What does convolution in the spatial dimension? |
It becomes multiplication. |
2C-L2 |
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What is the Fourier Transform of a Gaussian? |
It's a Gaussian. |
2C-L2 |
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What is ringing? |
When impulses from frequency space are removed. |
2C-L2 |
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What are some properties of Fourier Transforms? |
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2C-L2 |
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What are Fourier Transform smoothing pairs? |
An impulse function can be used to apply smoothing in frequency space. |
2C-L2 |
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What's the Fourier Transform of an impulse train? |
An impulse train |
2C-L3 |
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What are some complications with sampling image signals or sound waves? |
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2C-L3 |
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What is aliasing? |
Signals "traveling in disguise" as other frequencies. |
2C-L3 |
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How can anti-aliasing be one? |
1) Sample more often • Join the Mega-Pixel craze of the photo industry • But this can’t go on forever 2) Make the signal less “wiggly” • Get rid of some high frequencies • Will loose information • But it’s better than aliasing |
2C-L3 |
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What do lowpass filters do? |
Remove high frequencies to confidentially reconstruct low frequencies. |
2C-L3 |
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How can low frequencies be sampled with a comb? |
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2C-L3 |
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What happens if there is overlap of a signals in the Fourier transform space? |
The original signal can not be recovered. |
2C-L3 |
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What is an anti-aliasing filter? |
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What is the consequence of removing every other row and column from a photo to reduce file size? |
Aliasing |
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