Discover and read the best of Twitter Threads about #FourierTransform
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Finally, the thread (you didn't know) you have been waiting for š„³ "How can we use X-ray scattering to learn about the way the atoms sit in a #small #nanoparticle?" - lets use the Pair Distribution Function #PDF ! It's all about the neighbors 1/6 /@RPittkowski
To get information from small #nanoparticles, where periodic lattice planes are rare, we measure the X-ray scattering to very large scattering angles. This is called #Xray #totalscattering. So we need to come veeeery close with the detector to our sample.š±š¬ 2/6
Again, we integrate our scattering image (check up older tweets), but we are not done yet. More data treatment is necessary. We use a #Fouriertransform and transform from reciprocal (Q) space to #real #space - and there we have it, our PDF š3/6 
Let's fork this thread since people seem to be as fascinated by this topic as I amā¦
This process happens in nature. Any lens (a camera lens, the eye) 'calculates' the #FourierTransform of the object being imaged.
Read onā¦
[1/n]
#Fourier #Optics
This process happens in nature. Any lens (a camera lens, the eye) 'calculates' the #FourierTransform of the object being imaged.
Read onā¦
[1/n]
#Fourier #Optics
The Fourier Transform coincides with the plane of the lens. So small lenses cut out the higher spatial frequencies that are furthest from the centre.
Therefore, these higher frequencies do not go through the lens and they're lostā¦
[2/n]
Therefore, these higher frequencies do not go through the lens and they're lostā¦
[2/n]
So when the remaining frequencies are recombined at the image plane (say the back of the camera or the back of the eye), the terms that are needed for the fine detail are not thereā¦
The image is blurred.
This is diffraction.
[3/n]
The image is blurred.
This is diffraction.
[3/n]
What's an image made of?
There are many correct answers.
But the most fascinating one is: << sines & cosines >>
Read on if you're intriguedšš§µšŖ”
#python #images #fourier
There are many correct answers.
But the most fascinating one is: << sines & cosines >>
Read on if you're intriguedšš§µšŖ”
#python #images #fourier
*Any* image can be reconstructed from a series of sinusoidal gratings.
A sinusoidal grating looks like thisā¦
#sinusoidal #grating
A sinusoidal grating looks like thisā¦
#sinusoidal #grating
Itās called a sinusoidal grating because the grayscale values vary according to the sine function.
If you plot the values along a horizontal line of the grating, youāll get a plot of a sine function
If you plot the values along a horizontal line of the grating, youāll get a plot of a sine function
