Timeline for Why does the 2D-DFT of a sinus gradient not show energy along the diagonal straigh lines and only vertical/horizontal from the diagonal point?
Current License: CC BY-SA 4.0
9 events
| when toggle format | what | by | license | comment | |
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| Jan 11, 2022 at 18:16 | vote | accept | OuttaSpaceTime | ||
| Jan 11, 2022 at 14:58 | answer | added | Cris Luengo | timeline score: 2 | |
| Jan 11, 2022 at 8:58 | comment | added | OuttaSpaceTime |
No I haven't I am actually still wondering what the point of performing np.fft.ifftshift(grating) first is, because without this line I get the same result just less blurrly in some cases. Do you know what the point of performing the window function here is? I am not familiar with their application.
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| Jan 11, 2022 at 8:30 | comment | added | Cris Luengo |
Oh, you're referring to the streaks coming out of the two peaks. Did you look at the output of np.fft.ifftshift(grating)? It will contain a horizontal and vertical line where the sinus wave doesn't match up. If you apply a window function to your image first, you will strongly reduce the horizontal and vertical streaks.
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| Jan 11, 2022 at 7:48 | history | edited | OuttaSpaceTime | CC BY-SA 4.0 |
edited title
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| Jan 11, 2022 at 7:47 | comment | added | OuttaSpaceTime | thats right maybe putting it another way why do the points at diagonal line have energy along vertical and horizontal lines and not along the diagonal line? Thanks, I clarified the question. | |
| Jan 11, 2022 at 1:02 | comment | added | Cris Luengo | The origin is in the middle of the image, you have two peaks on either side of the origin, they sit on a line at an angle parallel to the direction of the sine wave. It is unclear to me why you say there is only energy along horizontal and vertical axes, because the axes are blank. | |
| S Jan 10, 2022 at 23:52 | review | First questions | |||
| Jan 11, 2022 at 1:14 | |||||
| S Jan 10, 2022 at 23:52 | history | asked | OuttaSpaceTime | CC BY-SA 4.0 |