Notes
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phase contains most of the structural information.
A way to think about the phase and amplitude information is that phase information describes the structure of an image, that is, where the power needs to be placed. And ampltiude information describes the intensity of that structure given a position.
Phase describes about the structure of the image where the power needs to be placed. Amplitude information describes intensity of the structure for positions.
- image with a single intensity pixel represent a boxcar function with the width the size of the pixel. When the number of the pixels in the image increases, it becomes a delta function (what?).
- FFT of a delta function gives a field of flat values (that is constant amplitude at all places in the image).
- When the pixel is at the center of the image, the phase is also flat. But the position of the pixel moves, the phase shows fringes pattern relative to the position of the pixel.
- moving the pixel on x axis, the phase remains constants on y axis. And vice versa.
- Moving the pixel around a circular path at a constant distance from the center, the phase frequency remains the same but the direction of phase changes.
- two point source fft
- resulting phase is the average of phases of all point sources with point source weights of their amplitude. (amplitude weighted average of the each phases)