Image Compression and the FFT 

yes was just about to type this. @steve maybe you should mention it

Just do it yourself in python.

Thanks!

Get a life!

@@yuurishibuya4797 well, I have everything i need, you name it...except a job in engineering field for which I had left my previous stable-cum-peaceful job.

Yes JPEG uses the DCT instead. The energy compaction of the DCT is much better than the Fourier Transform.

JPEG uses the DCT with blocks of pixels instead of the whole image at once. That's why badly jpg'd images have the odd blocky appearance.

They would be pretty heavily localized, but depend a lot from image to image. A picture of a white square on a black background would look kind of like a puddle after a rock was dropped in, with circles emmanating from the center.

@@Miyelsh thanks!

you could design an image to scatter over the fourier space, but regardless, the inverse operation to form the image only keeps the coefficients needed for the higher values, aka, you store their coordinates from the fourier space although one could totally design a way to store the coefficients that best fit the described set in the sketch, but you would need to study a very particular use case to apply it (like maybe how the fourier space looks on cartoony images or just compressing for text)

an image is simply a set of points(x,y) which they could be plotted like a signal

the fast fourier transform is a discrete transform meaning that the values it receives are in a discrete domain, it's not a continuous signal. it's extensively used in computing because of the discrete nature of digital stuff like audio and video

Likely some variation on this: black room, solid color background, special neon markers, camera behind *pane of glass,* and the picture is reversed (i.e., horizontally reflected) either before or after recording. Make sense?

@@danielsteel5251 Thanks. That explains. Sometimes he also includes his computer screen on the board. Guess there would be another projector involved. Anyways, it's really cool to see it. It looks so nice.

@@xiezhang1741 _... Guess there would be another projector involved. ..._ I'd guess that it was video editing, after the fact; not a projector.

@@danielsteel5251 That's unlikely, since he is precisely pointing to the right codes and images while he demonstrates the code implementations. It's gonna be really difficult to pretend something exists there while explaining very accurately and add the actual stuffs later.

@@xiezhang1741 His screen is being recorded and he can see it in a monitor while recording as he can be seen looking off camera into a monitor and it is then later edited in (and out) in post-production (post/post-prod) as necessary. If I'm wrong feel free to offer an alternate theory, but this seems the most likely and is what I would do.

The middle is low frequency waves. The very center is what's called the DC term, which is the overall average brightness of the image. The edges would be terms that are alternating every pixel, so you would only see those if you did something like took a picture of a screen door.